Add analyzer+codefix for applying RequiresUnsafe to pointer methods by Copilot · Pull Request #125196 · dotnet/runtime

Copilot · 2026-03-04T23:42:54Z

Description

Cherry-pick of PR #125195 (agocke/runtime). Adds a Roslyn analyzer and code fixer that warns on methods with the unsafe modifier but missing [RequiresUnsafe], and applies [RequiresUnsafe] to all unsafe methods in System.Private.CoreLib.

Analyzer (UnsafeMethodMissingRequiresUnsafeAnalyzer): Reports IL2900 on unsafe methods lacking [RequiresUnsafe]
Code fixer (UnsafeMethodMissingRequiresUnsafeCodeFixProvider): Adds [RequiresUnsafe] attribute automatically
Attribute application: 276 files across CoreCLR and shared CoreLib annotated with [RequiresUnsafe]
Merge conflict resolution:
- MdImport.cs — kept current LibraryImport/partial signature (diverged from fork's MethodImpl/extern), added [RequiresUnsafe]
- Sve.PlatformNotSupported.cs — resolved conflicts from SVE method signature changes (Vector<int>/Vector<uint> → Vector<long>/Vector<ulong>), ensured new unsafe pointer methods have [RequiresUnsafe]
Corner case exclusions:
- Reverted [RequiresUnsafe] from IntPtr.cs and UIntPtr.cs — pointers in those files do not imply RequiresUnsafe
- Removed [RequiresUnsafe] from Add<T>(void*, int) and Subtract<T>(void*, int) in Unsafe.cs — these methods do not dereference the pointer
- Removed [RequiresUnsafe] from Alloc and AllocZeroed in NativeMemory.cs and NativeMemory.Unix.cs — returning a pointer is not inherently unsafe, only dereferencing it would be
Cleanup: Reverted 43 files that had only unnecessary using System.Diagnostics.CodeAnalysis; additions without any [RequiresUnsafe] usage (leftover from code fixer iterations), and restored UTF-8 BOMs in 20 files that were inadvertently stripped by the fork's editor
Scope note: [RequiresUnsafe] on Add, Subtract, AddByteOffset, and SubtractByteOffset methods returning ref T in Unsafe.cs was reverted to keep this PR focused on pointer-based methods; non-pointer RequiresUnsafe changes will be grouped into a separate PR

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Add a new DiagnosticAnalyzer (UnsafeMethodMissingRequiresUnsafeAnalyzer) that warns when a method, constructor, or local function has the 'unsafe' modifier but is not annotated with [RequiresUnsafe]. Add a matching CodeFixProvider that adds the [RequiresUnsafe] attribute to the flagged declaration. Both are #if DEBUG guarded and enabled via the existing EnableUnsafeAnalyzer MSBuild property. New diagnostic: IL5004 (UnsafeMethodMissingRequiresUnsafe) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Now based on methods with pointer types, rather than methods with .

…r-content-125195 # Conflicts: # src/libraries/Common/src/Interop/Unix/System.Native/Interop.Futex.cs # src/libraries/System.Private.CoreLib/src/System/Threading/LowLevelFutex.Unix.cs

- Remove lambda/anonymous method break in RequiresUnsafeAnalyzer so unsafe context flows through nested lambdas (matching C# semantics) - Add FieldDeclarationSyntax to IsInRequiresScope for unsafe field initializers - Remove [RequiresUnsafe] from files compiled outside CoreLib (Common/, nativeaot/Runtime.Base/, Resources/) where the attribute is unavailable - Add tests for lambda-in-unsafe-method, anonymous delegate, and field initializer scenarios Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Use the DiagnosticSeverity.Info overload so IL5004 shows as a suggestion rather than a warning/error in builds. Update tests to expect Info severity. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…r-content-125195 # Conflicts: # src/coreclr/System.Private.CoreLib/src/System/AppContext.CoreCLR.cs # src/coreclr/System.Private.CoreLib/src/System/StartupHookProvider.CoreCLR.cs

src/libraries/System.Private.CoreLib/src/System/IntPtr.cs

Co-authored-by: agocke <515774+agocke@users.noreply.github.com>

src/libraries/System.Private.CoreLib/src/System/Runtime/CompilerServices/Unsafe.cs

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/NativeMemory.cs

Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

jkotas · 2026-03-11T06:17:39Z

Revert changes to Unsafe.Add/Subtract

This does not look right to me.

Unsafe.Add/Subtract on byrefs need RequiresUnsafe. Otherwise, all byref dereferences would have to be unsafe - I do not think we want that.

EDIT: I see your comment above. This PR is not trying to be complete; you are leaving it for later.

agocke · 2026-03-11T18:53:11Z

@copilot please merge with main and resolve merge conflicts

…/duplicate-pr-content-125195 # Conflicts: # src/libraries/System.Private.CoreLib/src/System/Runtime/Intrinsics/Arm/Sve.PlatformNotSupported.cs

Copilot · 2026-03-11T19:01:52Z

@copilot please merge with main and resolve merge conflicts

Merged with main and resolved merge conflicts in Sve.PlatformNotSupported.cs in 7c9bf4b. The conflict was caused by method signature changes (old Vector<int>/Vector<uint> overloads replaced with Vector<long>/Vector<ulong> versions). Added [RequiresUnsafe] to the new unsafe methods.

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agocke · 2026-03-13T20:50:47Z

I think this is ready -- it only annotates System.Private.CoreLib so once everything goes through here we can take on the remaining libraries.

jkotas · 2026-03-14T13:48:34Z

src/coreclr/nativeaot/Runtime.Base/src/System/Runtime/StackFrameIterator.cs


 using System.Diagnostics;
 using System.Runtime.InteropServices;
+using System.Diagnostics.CodeAnalysis;


@copilot This file has unnecessary whitespace only changes. Please revert the changes in this file. Also, check the rest of the PR for the same issue

Reverted StackFrameIterator.cs and found 42 additional files with the same issue (unnecessary using System.Diagnostics.CodeAnalysis; additions without any [RequiresUnsafe]). Also restored UTF-8 BOMs that were inadvertently stripped by the fork's editor in 20 files. All fixed in 06eb913.

Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

jkotas · 2026-03-14T22:48:48Z

The annotations look fine to me.

Initial plan

003645d

Copilot AI assigned Copilot and agocke Mar 4, 2026

github-project-automation bot added this to AppModel Mar 4, 2026

Copilot started work on behalf of agocke March 4, 2026 23:42 View session

github-actions bot added the area-Infrastructure-libraries label Mar 4, 2026

Copilot AI changed the title ~~[WIP] Add exact contents from PR 125195~~ Add analyzer+codefix for unsafe methods missing [RequiresUnsafe] Mar 4, 2026

Copilot finished work on behalf of agocke March 4, 2026 23:48

dotnet-policy-service bot added the linkable-framework Issues associated with delivering a linker friendly framework label Mar 4, 2026

build-analysis bot mentioned this pull request Mar 5, 2026

[android][arm64] System.Net.Sockets.Tests.SendTo_SyncForceNonBlocking.Datagram_UDP_ShouldImplicitlyBindLocalEndpoint fails with NetworkUnreachable #120526

Open

agocke added 2 commits March 5, 2026 14:44

Change analyzer/codefix implementation

315b2b0

Now based on methods with pointer types, rather than methods with .

Mark methods with pointer types as

ce61325

agocke mentioned this pull request Mar 5, 2026

Add analyzer+codefix for unsafe methods->RequiresUnsafe #125195

Closed

agocke and others added 4 commits March 5, 2026 16:10

Merge remote-tracking branch 'upstream/main' into copilot/duplicate-p…

a5aa1e8

…r-content-125195 # Conflicts: # src/libraries/Common/src/Interop/Unix/System.Native/Interop.Futex.cs # src/libraries/System.Private.CoreLib/src/System/Threading/LowLevelFutex.Unix.cs

Set IL5004 diagnostic severity to Info

c4b5726

Use the DiagnosticSeverity.Info overload so IL5004 shows as a suggestion rather than a warning/error in builds. Update tests to expect Info severity. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Remove [RequiresUnsafe] from AsPointer

a6490f4

agocke force-pushed the copilot/duplicate-pr-content-125195 branch from c08c9a1 to a6490f4 Compare March 6, 2026 18:35

agocke added 3 commits March 6, 2026 10:50

Merge remote-tracking branch 'upstream/main' into copilot/duplicate-p…

77fc1e7

…r-content-125195 # Conflicts: # src/coreclr/System.Private.CoreLib/src/System/AppContext.CoreCLR.cs # src/coreclr/System.Private.CoreLib/src/System/StartupHookProvider.CoreCLR.cs

Annotate EventProvider

c36349c

Include in Microsoft.Bcl.Memory

eeb56b0

jkotas reviewed Mar 6, 2026

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src/libraries/System.Private.CoreLib/src/System/IntPtr.cs Outdated Show resolved Hide resolved

Copilot started work on behalf of agocke March 6, 2026 23:08 View session

Revert [RequiresUnsafe] from IntPtr.cs and UIntPtr.cs

c3d93e4

Co-authored-by: agocke <515774+agocke@users.noreply.github.com>

Copilot finished work on behalf of agocke March 6, 2026 23:13

jkotas reviewed Mar 6, 2026

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src/libraries/System.Private.CoreLib/src/System/Runtime/CompilerServices/Unsafe.cs Outdated Show resolved Hide resolved

Copilot started work on behalf of jkotas March 6, 2026 23:16 View session

jkotas reviewed Mar 6, 2026

View reviewed changes

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/NativeMemory.cs Outdated Show resolved Hide resolved

Remove [RequiresUnsafe] from Add and Subtract methods in Unsafe.cs

66211d8

Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Remove more conservative RequiresUnsafe annotations

9a002a8

agocke changed the title ~~Add analyzer+codefix for unsafe methods missing [RequiresUnsafe]~~ Add analyzer+codefix for applying RequiresUnsafe to pointer methods Mar 10, 2026

Copilot started work on behalf of agocke March 11, 2026 18:53 View session

Merge branch 'main' of https://github.com/dotnet/runtime into copilot…

7c9bf4b

…/duplicate-pr-content-125195 # Conflicts: # src/libraries/System.Private.CoreLib/src/System/Runtime/Intrinsics/Arm/Sve.PlatformNotSupported.cs

Copilot finished work on behalf of agocke March 11, 2026 19:02

agocke marked this pull request as ready for review March 11, 2026 23:17

agocke requested review from MichalStrehovsky and sbomer as code owners March 11, 2026 23:17

Copilot AI review requested due to automatic review settings March 11, 2026 23:17

Copilot AI reviewed Mar 11, 2026

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Copilot started reviewing on behalf of agocke March 11, 2026 23:26 View session

jkotas reviewed Mar 14, 2026

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Copilot started work on behalf of jkotas March 14, 2026 13:48 View session

Revert whitespace-only changes and restore BOMs in 63 files

06eb913

Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot AI requested a review from jkotas March 14, 2026 13:59

Copilot finished work on behalf of jkotas March 14, 2026 13:59

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Add analyzer+codefix for applying RequiresUnsafe to pointer methods#125196

Add analyzer+codefix for applying RequiresUnsafe to pointer methods#125196
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