diff --git a/src/N.SourceGenerators.UnionTypes/N.SourceGenerators.UnionTypes.csproj b/src/N.SourceGenerators.UnionTypes/N.SourceGenerators.UnionTypes.csproj
index 33cc708..0a3d399 100644
--- a/src/N.SourceGenerators.UnionTypes/N.SourceGenerators.UnionTypes.csproj
+++ b/src/N.SourceGenerators.UnionTypes/N.SourceGenerators.UnionTypes.csproj
@@ -10,7 +10,7 @@
         <IsRoslynComponent>true</IsRoslynComponent>
         <IsPackable>true</IsPackable>
         <PackageOutputPath>./nupkg</PackageOutputPath>
-        <VersionPrefix>0.28.0</VersionPrefix>
+        <VersionPrefix>0.28.1</VersionPrefix>
         <EnableNETAnalyzers>true</EnableNETAnalyzers>
         <NoWarn>$(NoWarn);NU5128</NoWarn>
     </PropertyGroup>
diff --git a/src/N.SourceGenerators.UnionTypes/UnionTypesGenerator.Attributes.cs b/src/N.SourceGenerators.UnionTypes/UnionTypesGenerator.Attributes.cs
index 2078704..857df1f 100644
--- a/src/N.SourceGenerators.UnionTypes/UnionTypesGenerator.Attributes.cs
+++ b/src/N.SourceGenerators.UnionTypes/UnionTypesGenerator.Attributes.cs
@@ -18,12 +18,15 @@ public partial class UnionTypesGenerator
         #if NETCOREAPP3_1_OR_GREATER
         #nullable enable
         #endif
-        using System;
-        using System.Runtime.CompilerServices;
+        using Attribute = global::System.Attribute;
+        using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+        using AttributeTargets = global::System.AttributeTargets;
+        using Type = global::System.Type;
+        using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
         
         namespace N.SourceGenerators.UnionTypes
         {
-            [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+            [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
             [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
             internal sealed class UnionTypeAttribute : Attribute
             {
@@ -60,12 +63,13 @@ public UnionTypeAttribute(Type type, string alias = null, [CallerLineNumber] int
         #if NETCOREAPP3_1_OR_GREATER
         #nullable enable
         #endif
-        using System;
-        using System.Runtime.CompilerServices;
+        using Attribute = global::System.Attribute;
+        using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+        using AttributeTargets = global::System.AttributeTargets;
         
         namespace N.SourceGenerators.UnionTypes
         {
-            [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+            [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
             [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
             internal sealed class GenericUnionTypeAttribute : Attribute
             {
@@ -87,12 +91,13 @@ internal sealed class GenericUnionTypeAttribute : Attribute
         #if NETCOREAPP3_1_OR_GREATER
         #nullable enable
         #endif
-        using System;
-        using System.Runtime.CompilerServices;
+        using Attribute = global::System.Attribute;
+        using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+        using AttributeTargets = global::System.AttributeTargets;
         
         namespace N.SourceGenerators.UnionTypes
         {
-            [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+            [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
             [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
             internal sealed class JsonPolymorphicUnionAttribute : Attribute
             {
@@ -110,12 +115,14 @@ internal sealed class JsonPolymorphicUnionAttribute : Attribute
         #if NETCOREAPP3_1_OR_GREATER
         #nullable enable
         #endif
-        using System;
-        using System.Runtime.CompilerServices;
+        using Attribute = global::System.Attribute;
+        using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+        using AttributeTargets = global::System.AttributeTargets;
+        using Type = global::System.Type;
         
         namespace N.SourceGenerators.UnionTypes
         {
-            [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+            [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
             [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
             sealed class UnionConverterFromAttribute : Attribute
             {
@@ -134,12 +141,14 @@ public UnionConverterFromAttribute(Type fromType)
         #if NETCOREAPP3_1_OR_GREATER
         #nullable enable
         #endif
-        using System;
-        using System.Runtime.CompilerServices;
+        using Attribute = global::System.Attribute;
+        using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+        using AttributeTargets = global::System.AttributeTargets;
+        using Type = global::System.Type;
         
         namespace N.SourceGenerators.UnionTypes
         {
-            [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+            [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
             [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
             sealed class UnionConverterToAttribute : Attribute
             {
@@ -157,12 +166,14 @@ public UnionConverterToAttribute(Type toType)
         #if NETCOREAPP3_1_OR_GREATER
         #nullable enable
         #endif
-        using System;
-        using System.Runtime.CompilerServices;
+        using Attribute = global::System.Attribute;
+        using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+        using AttributeTargets = global::System.AttributeTargets;
+        using Type = global::System.Type;
         
         namespace N.SourceGenerators.UnionTypes
         {
-            [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+            [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
             [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
             sealed class UnionConverterAttribute : Attribute
             {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverter#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ExternalConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverter#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.FromConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverter#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.StaticExternalConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverter#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/ConverterGeneratorTests.ToConverterReportsDiagnostic#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.InvalidTypeReportsAllDiagnostics#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.NotPartialTypeReportsDiagnostics#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantAliasDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantOrderDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/DiagnosticTests.VariantTypeDuplicateReportsDiagnostics#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-class#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.CSharp73_partial-struct#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DifferentNamespaces#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-class#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_partial-struct#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.DoNotOverrideToString_readonly-partial-struct#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.ExplicitStructLayout#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-class#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_partial-struct#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithNamespace_readonly-partial-struct#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-False#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-class-exclude-True#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-False#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_partial-struct-exclude-True#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-False#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GeneratorTests.WithoutNamespace_readonly-partial-struct-exclude-True#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.OnlyGenericTypes#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithAlias#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/GenericUnionTests.WithCustomUnionType#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/JsonTests.ItDoesNotFail#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/NullableValueTests.UseAllowNullAttribute#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_0#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#GenericUnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#GenericUnionTypeAttribute.g.verified.cs
index 29d7087..14d2d67 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#GenericUnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#GenericUnionTypeAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.GenericParameter, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class GenericUnionTypeAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#JsonPolymorphicUnionAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#JsonPolymorphicUnionAttribute.g.verified.cs
index 52628cf..f7fdf30 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#JsonPolymorphicUnionAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#JsonPolymorphicUnionAttribute.g.verified.cs
@@ -6,12 +6,13 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class JsonPolymorphicUnionAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterAttribute.g.verified.cs
index 3a119c2..377c3b0 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterAttribute.g.verified.cs
@@ -2,12 +2,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterFromAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterFromAttribute.g.verified.cs
index 43174eb..436171e 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterFromAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterFromAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterFromAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterToAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterToAttribute.g.verified.cs
index b72ef9e..7722d16 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterToAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionConverterToAttribute.g.verified.cs
@@ -6,12 +6,14 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     sealed class UnionConverterToAttribute : Attribute
     {
diff --git a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionTypeAttribute.g.verified.cs b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionTypeAttribute.g.verified.cs
index 72e4fc5..fecdc25 100644
--- a/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionTypeAttribute.g.verified.cs
+++ b/tests/N.SourceGenerators.UnionTypes.Tests/Snapshots/TwoAssemblyTests.UnionConverterFromInOtherAssembly_1#UnionTypeAttribute.g.verified.cs
@@ -6,12 +6,15 @@
 #if NETCOREAPP3_1_OR_GREATER
 #nullable enable
 #endif
-using System;
-using System.Runtime.CompilerServices;
+using Attribute = global::System.Attribute;
+using AttributeUsageAttribute = global::System.AttributeUsageAttribute;
+using AttributeTargets = global::System.AttributeTargets;
+using Type = global::System.Type;
+using CallerLineNumber = System.Runtime.CompilerServices.CallerLineNumberAttribute;
 
 namespace N.SourceGenerators.UnionTypes
 {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
+    [AttributeUsageAttribute(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = true)]
     [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
     internal sealed class UnionTypeAttribute : Attribute
     {