Fix Delegate.GetHashCode for type-equivalent delegates by Copilot · Pull Request #130542 · dotnet/runtime

Copilot · 2026-07-11T03:41:19Z

Fix Delegate.GetHashCode to return same hashcodes for type-equivalent delegates pointing to the same method. Delegate.Equals returns true for such delegates. GetHashCode contract requires hashcode to be the same in that case.

Found during codereview of #99200

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

…bute Replace plain DelegateTypeA/DelegateTypeB (same signature but different names, which can never be type-equivalent) with a proper cross-assembly type-equivalent delegate pair using [TypeIdentifier] attribute as defined in .NET type equivalence docs. - Add TestDelegateEquivalentTypeAssembly with System.Tests.EquivalentDelegate decorated with [TypeIdentifier("guid-scope", "guid-identifier")] - Declare System.Tests.EquivalentDelegate with the same [TypeIdentifier] values in DelegateTests.cs (namespace-level, not nested, to avoid enclosing-type equivalence requirements) - Update tests to use [ConditionalFact(IsTypeEquivalenceSupported)] and load the second assembly at runtime via Assembly.LoadFrom - Add ProjectReference in System.Runtime.Tests.csproj so the assembly is built and deployed alongside the test DLL Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

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

…em.TestEquivalentTypes; remove AutoGenerateBindingRedirects Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

jkotas

@copilot Address feedback

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

Copilot · 2026-07-11T13:26:42Z

@copilot Address feedback

All feedback addressed in the latest commit:

TestEquivalentTypes/System.TestEquivalentTypes.cs is now added to System.Runtime.Tests.csproj via <Compile Include> — the EquivalentDelegate definition at the bottom of DelegateTests.cs has been removed.
The two tests are merged into TypeEquivalentDelegatesPointingToSameMethod_AreEqualAndHaveSameHashCode.
Added Assert.False(typeof(EquivalentDelegate).Equals(otherDelegateType)) and Assert.True(typeof(EquivalentDelegate).IsEquivalentTo(otherDelegateType)).
Switched from Type.GetType to Assembly.Load("System.TestEquivalentTypes").GetType(...) to reliably load the satellite assembly and fix the Assert.NotNull CI failure.

Co-authored-by: Michał Petryka <35800402+MichalPetryka@users.noreply.github.com>

dotnet-policy-service · 2026-07-13T03:09:49Z

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Copilot

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Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

… instead of 0 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot · 2026-07-13T04:39:42Z

@jkotas I've opened a new pull request, #130597, to work on those changes. Once the pull request is ready, I'll request review from you.

…fix PR (#130597)

Copilot

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Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

Co-authored-by: Michał Petryka <35800402+MichalPetryka@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

MichalPetryka · 2026-07-14T00:43:12Z

Can we merge this when CI is done so that I can rebase my other PR?

Co-authored-by: Aaron R Robinson <arobins@microsoft.com>

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

Copilot AI and others added 2 commits July 11, 2026 01:02

Add test for delegate equality and GetHashCode across equivalent dele…

2b991fc

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

Copilot AI assigned Copilot and jkotas Jul 11, 2026

Copilot AI requested review from Copilot and removed request for Copilot July 11, 2026 03:41

Copilot created this pull request from a session on behalf of jkotas July 11, 2026 03:41 View session

github-actions Bot added the area-System.Numerics label Jul 11, 2026

jkotas reviewed Jul 11, 2026

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Comment thread src/libraries/System.Runtime/tests/System.Runtime.Tests/System/DelegateTests.cs Outdated

jkotas reviewed Jul 11, 2026

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Comment thread ...m.Runtime.Tests/TestDelegateEquivalentTypeAssembly/TestDelegateEquivalentTypeAssembly.csproj Outdated

Copilot started work on behalf of jkotas July 11, 2026 04:53 View session

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Comment thread src/libraries/System.Runtime/tests/System.Runtime.Tests/System.Runtime.Tests.csproj Outdated

Replace Assembly.LoadFrom with Type.GetType in delegate equivalence t…

91fc6f3

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

Copilot AI requested review from Copilot and jkotas and removed request for Copilot July 11, 2026 04:57

Copilot finished work on behalf of jkotas July 11, 2026 04:57

Copilot started work on behalf of jkotas July 11, 2026 04:59 View session

Rename TestDelegateEquivalentTypeAssembly to TestEquivalentTypes/Syst…

32d3443

…em.TestEquivalentTypes; remove AutoGenerateBindingRedirects Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Copilot AI requested review from Copilot and removed request for Copilot July 11, 2026 05:02

Copilot finished work on behalf of jkotas July 11, 2026 05:03

jkotas mentioned this pull request Jul 11, 2026

Optimize and simplify delegate layout #99200

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build-analysis Bot mentioned this pull request Jul 11, 2026

Helix: System.IO.IOException: No space left on device #128758

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jkotas reviewed Jul 11, 2026

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Copilot started work on behalf of jkotas July 11, 2026 13:14 View session

Address review feedback: merge tests, fix assembly loading, add IsEqu…

4bc06fd

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

Copilot AI requested review from Copilot and removed request for Copilot July 11, 2026 13:26

Update src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs

ffe2b01

Co-authored-by: Michał Petryka <35800402+MichalPetryka@users.noreply.github.com>

Copilot started reviewing on behalf of jkotas July 13, 2026 03:02 View session

jkotas temporarily deployed to copilot-pat-pool July 13, 2026 03:03 — with GitHub Actions Inactive

jkotas marked this pull request as ready for review July 13, 2026 03:03

jkotas approved these changes Jul 13, 2026

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jkotas changed the title ~~Fix delegate type equivalence tests to use proper TypeIdentifier-based equivalence~~ Fix Delegate.GetHashCode for type equivalent delegates Jul 13, 2026

Copilot AI reviewed Jul 13, 2026

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Comment thread src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs

Fix hash collisions: use type name hash for type-equivalent delegates…

80157ba

… instead of 0 Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

jkotas approved these changes Jul 13, 2026

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Copilot AI mentioned this pull request Jul 13, 2026

[WIP] Revert last commit to address feedback on Delegate.GetHashCode fix PR #130597

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[WIP] Revert last commit to address feedback on Delegate.GetHashCode …

7f3c114

…fix PR (#130597)

Copilot AI reviewed Jul 13, 2026

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build-analysis Bot mentioned this pull request Jul 13, 2026

[QUIC] Sporadic long running tests #119763

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AaronRobinsonMSFT reviewed Jul 13, 2026

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Comment thread src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs

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Comment thread src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs Outdated

Update src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs

4946c56

Co-authored-by: Michał Petryka <35800402+MichalPetryka@users.noreply.github.com>

Copilot AI reviewed Jul 13, 2026

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Comment thread src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs

AaronRobinsonMSFT reviewed Jul 14, 2026

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Comment thread src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs

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Comment thread src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs Outdated

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Comment thread src/coreclr/System.Private.CoreLib/src/System/Delegate.CoreCLR.cs Outdated

Apply suggestions from code review

ff666a5

Co-authored-by: Aaron R Robinson <arobins@microsoft.com>

Copilot AI reviewed Jul 14, 2026

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Copilot AI commented Jul 11, 2026

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Copilot AI commented Jul 11, 2026 •

edited by jkotas

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