Fix trimability in a couple more test projects

src/libraries/System.Diagnostics.EventLog/tests/EventLogMessagesTests.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Eventing.Reader;
 using System.IO;
 using System.Reflection;
@@ -12,6 +13,7 @@ namespace System.Diagnostics.Tests
     public class EventLogMessagesTests
     {
         [Fact]
+        [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "The test asserts the assembly contains no types; trimming cannot make an empty assembly emptier.")]
         public void EventLogMessagesContainsNoTypes()
         {
             Assembly messageAssembly = Assembly.Load("System.Diagnostics.EventLog.Messages");

src/libraries/System.Diagnostics.EventLog/tests/System.Diagnostics.EventLog.Tests.csproj

@@ -2,8 +2,6 @@
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetFrameworkCurrent)</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <!-- https://github.com/dotnet/runtime/issues/126862 -->
-    <EnableTrimAnalyzer>false</EnableTrimAnalyzer>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="EventInstanceTests.cs" />

src/libraries/System.Formats.Tar/tests/System.Formats.Tar.Tests.csproj

@@ -4,8 +4,6 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <StringResourcesPath>$(MSBuildProjectDirectory)\..\src\Resources\Strings.resx</StringResourcesPath>
     <IncludeRemoteExecutor>true</IncludeRemoteExecutor>
-    <!-- https://github.com/dotnet/runtime/issues/126862 -->
-    <EnableTrimAnalyzer>false</EnableTrimAnalyzer>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="$(CommonTestPath)System\IO\TempDirectory.cs" Link="Common\System\IO\TempDirectory.cs" />

src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.ComponentModel;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Threading;
 using Xunit;
@@ -17,7 +18,7 @@ public class TestSite : ISite
             public bool DesignMode => designMode;
             public IComponent Component => null;
             public IContainer Container => null;
-            public string Name { get; set; }
+            public string Name { get; [RequiresUnreferencedCode("The Type of components in the container cannot be statically discovered to validate the name.")] set; }
             public object GetService(Type serviceType) => null;
         }
 

src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.unit.cs

@@ -289,7 +289,7 @@ public void FileSystemWatcher_NotifyFilter()
             FileSystemWatcher watcher = new FileSystemWatcher();
             Assert.Equal(NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName, watcher.NotifyFilter);
 
-            var notifyFilters = Enum.GetValues(typeof(NotifyFilters)).Cast<NotifyFilters>();
+            var notifyFilters = Enum.GetValues<NotifyFilters>();
             foreach (NotifyFilters filterValue in notifyFilters)
             {
                 watcher.NotifyFilter = filterValue;

src/libraries/System.IO.FileSystem.Watcher/tests/System.IO.FileSystem.Watcher.Tests.csproj

@@ -4,9 +4,6 @@
     <IncludeRemoteExecutor>true</IncludeRemoteExecutor>
     <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetCoreAppCurrent)-linux;$(NetCoreAppCurrent)-osx;$(NetCoreAppCurrent)-maccatalyst;$(NetCoreAppCurrent)-freebsd</TargetFrameworks>
     <IgnoreForCI Condition="'$(TargetOS)' == 'browser' or '$(TargetOS)' == 'iossimulator' or '$(TargetOS)' == 'ios' or '$(TargetOS)' == 'tvossimulator' or '$(TargetOS)' == 'tvos'">true</IgnoreForCI>
-    <!-- https://github.com/dotnet/runtime/issues/126862 -->
-    <EnableTrimAnalyzer>false</EnableTrimAnalyzer>
-    <EnableAotAnalyzer>false</EnableAotAnalyzer>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="AssemblyInfo.cs" />

src/libraries/System.IO.FileSystem.Watcher/tests/Utility/FileSystemWatcherTest.cs

@@ -465,7 +465,7 @@ public static bool TryErrorEvent(FileSystemWatcher watcher, Action action, Actio
 
         public static IEnumerable<object[]> FilterTypes()
         {
-            foreach (NotifyFilters filter in Enum.GetValues(typeof(NotifyFilters)))
+            foreach (NotifyFilters filter in Enum.GetValues<NotifyFilters>())
                 yield return new object[] { filter };
         }
 

src/libraries/System.IO.Hashing/tests/NonCryptoHashTestDriver.cs

@@ -3,11 +3,13 @@
 
 using System.Buffers.Binary;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using Xunit;
 
 namespace System.IO.Hashing.Tests
 {
+    [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)]
     public abstract class NonCryptoHashTestDriver
     {
         private readonly int _hashLengthInBytes;

src/libraries/System.IO.Hashing/tests/System.IO.Hashing.Tests.csproj

@@ -3,8 +3,6 @@
   <PropertyGroup>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <TargetFrameworks>$(NetCoreAppCurrent);$(NetFrameworkCurrent)</TargetFrameworks>
-    <!-- https://github.com/dotnet/runtime/issues/126862 -->
-    <EnableTrimAnalyzer>false</EnableTrimAnalyzer>
   </PropertyGroup>
 
   <ItemGroup>
@@ -36,6 +34,12 @@
     </Compile>
   </ItemGroup>
 
+  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
+    <Compile Include="$(CoreLibSharedDir)System\Diagnostics\CodeAnalysis\DynamicallyAccessedMembersAttribute.cs" />
+    <Compile Include="$(CoreLibSharedDir)System\Diagnostics\CodeAnalysis\DynamicallyAccessedMemberTypes.cs" />
+    <Compile Include="$(CoreLibSharedDir)System\Runtime\CompilerServices\CompilerLoweringPreserveAttribute.cs" />
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="..\src\System.IO.Hashing.csproj" />
   </ItemGroup>

src/libraries/System.Runtime/tests/System.IO.Tests/System.IO.Tests.csproj

@@ -6,8 +6,6 @@
     <IncludeRemoteExecutor>true</IncludeRemoteExecutor>
     <TargetFramework>$(NetCoreAppCurrent)</TargetFramework>
     <XunitShowProgress>true</XunitShowProgress>
-    <!-- https://github.com/dotnet/runtime/issues/126862 -->
-    <EnableTrimAnalyzer>false</EnableTrimAnalyzer>
   </PropertyGroup>
   <PropertyGroup Condition="'$(TargetOS)' == 'browser' and '$(WasmEnableThreads)' == 'true'">
     <WasmXHarnessMaxParallelThreads>1</WasmXHarnessMaxParallelThreads>

src/libraries/System.Runtime/tests/System.IO.Tests/TextWriter/TextWriterTests.cs

@@ -4,6 +4,7 @@
 using System.CodeDom.Compiler;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Linq;
 using System.Reflection;
@@ -1049,6 +1050,7 @@ public async Task CreateBroadcasting_DelegatesToAllWriters()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotBuiltWithAggressiveTrimming))]
+        [UnconditionalSuppressMessage("Trimming", "IL2075", Justification = "Test is skipped under trimming via IsNotBuiltWithAggressiveTrimming.")]
         public void CreateBroadcasting_AllMethodsOverridden()
         {
             HashSet<string> exempted = ["Close", "Dispose", "get_NewLine", "set_NewLine"];