[release/10.0] Fix Crossgen2 variance validation for type constraints by jtschuster · Pull Request #133118 · dotnet/runtime

jtschuster · 2026-09-02T18:26:40Z

Backport of #132809 to release/10.0

Customer Impact

Customer reported
Found internally

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit READYTORUN_FLAG_SkipTypeValidation, disabling the perf optimization.

This change:

removes the invalid variance check for type-owned generic constraints
aligns interface method signature validation with the VM by checking all instance methods and - virtual methods, including static virtual and static abstract declarations
adds a ReadyToRun regression test based on the reported constraint pattern

Fixes#132724

Regression

Yes.
No
Reduce types loaded on startup significantly #120459 introduced the regression.

Testing

Testing was done on main and release/11.0-rc1. release/10.0 does not have the test project that the test was added to. The test project was manually built locally and contained the expected READYTORUN_FLAG_SkipTypeValidation flag.

Risk

Low. The change makes the validation match the ECMA spec and matches the validation in the runtime.

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit `READYTORUN_FLAG_SkipTypeValidation`. This change: - removes the invalid variance check for type-owned generic constraints - aligns interface method signature validation with the VM by checking all instance methods and virtual methods, including static virtual and static abstract declarations - adds a ReadyToRun regression test based on the reported constraint pattern Fixesdotnet#132724 > [!NOTE] > This pull request was created with GitHub Copilot. (cherry picked from commit 65c1f69)

azure-pipelines · 2026-09-02T18:27:22Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-09-02T18:28:01Z

Tagging subscribers to this area: @dotnet/crossgen-contrib
See info in area-owners.md if you want to be subscribed.

Copilot

🟢 Approval recommended

The changes are narrowly scoped to the intended validation logic and align the checks with the stated ECMA/VM behavior without introducing new observable failure paths in the modified regions.

Pull request overview

Backports a Crossgen2 type-validation fix to release/10.0 so valid variant interfaces with type-owned generic constraints no longer fail variance validation (and thus can retain READYTORUN_FLAG_SkipTypeValidation for the intended perf optimization).

Changes:

Expands interface method signature variance validation to cover all instance methods and all virtual methods (including static abstract/static virtual interface members).
Removes the incorrect variance validation applied to a generic type’s own generic parameter constraints (per ECMA-335 II.9.7).

File summaries

File	Description
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/TypeValidationChecker.cs	Fixes Crossgen2 variance validation rules for type-owned constraints and broadens interface method signature checking to match VM behavior.

Review details

Files reviewed: 1/1 changed files
Comments generated: 0
Review effort level: Lite

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JulieLeeMSFT · 2026-09-03T18:42:47Z

/ba-g unrelated known issues.

jtschuster · 2026-09-02T18:26:40Z

Backport of #132809 to release/10.0

Customer Impact

Customer reported
Found internally

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit READYTORUN_FLAG_SkipTypeValidation, disabling the perf optimization.

This change:

removes the invalid variance check for type-owned generic constraints
aligns interface method signature validation with the VM by checking all instance methods and - virtual methods, including static virtual and static abstract declarations
adds a ReadyToRun regression test based on the reported constraint pattern

Fixes#132724

Regression

Yes.
No
Reduce types loaded on startup significantly #120459 introduced the regression.

Testing

Testing was done on main and release/11.0-rc1. release/10.0 does not have the test project that the test was added to. The test project was manually built locally and contained the expected READYTORUN_FLAG_SkipTypeValidation flag.

Risk

Low. The change makes the validation match the ECMA spec and matches the validation in the runtime.

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit `READYTORUN_FLAG_SkipTypeValidation`. This change: - removes the invalid variance check for type-owned generic constraints - aligns interface method signature validation with the VM by checking all instance methods and virtual methods, including static virtual and static abstract declarations - adds a ReadyToRun regression test based on the reported constraint pattern Fixesdotnet#132724 > [!NOTE] > This pull request was created with GitHub Copilot. (cherry picked from commit 65c1f69)

azure-pipelines · 2026-09-02T18:27:22Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-09-02T18:28:01Z

Tagging subscribers to this area: @dotnet/crossgen-contrib
See info in area-owners.md if you want to be subscribed.

Copilot

🟢 Approval recommended

The changes are narrowly scoped to the intended validation logic and align the checks with the stated ECMA/VM behavior without introducing new observable failure paths in the modified regions.

Pull request overview

Backports a Crossgen2 type-validation fix to release/10.0 so valid variant interfaces with type-owned generic constraints no longer fail variance validation (and thus can retain READYTORUN_FLAG_SkipTypeValidation for the intended perf optimization).

Changes:

Expands interface method signature variance validation to cover all instance methods and all virtual methods (including static abstract/static virtual interface members).
Removes the incorrect variance validation applied to a generic type’s own generic parameter constraints (per ECMA-335 II.9.7).

File summaries

File	Description
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/TypeValidationChecker.cs	Fixes Crossgen2 variance validation rules for type-owned constraints and broadens interface method signature checking to match VM behavior.

Review details

Files reviewed: 1/1 changed files
Comments generated: 0
Review effort level: Lite

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JulieLeeMSFT · 2026-09-03T18:42:47Z

/ba-g unrelated known issues.

jtschuster · 2026-09-02T18:26:40Z

Backport of #132809 to release/10.0

Customer Impact

Customer reported
Found internally

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit READYTORUN_FLAG_SkipTypeValidation, disabling the perf optimization.

This change:

removes the invalid variance check for type-owned generic constraints
aligns interface method signature validation with the VM by checking all instance methods and - virtual methods, including static virtual and static abstract declarations
adds a ReadyToRun regression test based on the reported constraint pattern

Fixes#132724

Regression

Yes.
No
Reduce types loaded on startup significantly #120459 introduced the regression.

Testing

Testing was done on main and release/11.0-rc1. release/10.0 does not have the test project that the test was added to. The test project was manually built locally and contained the expected READYTORUN_FLAG_SkipTypeValidation flag.

Risk

Low. The change makes the validation match the ECMA spec and matches the validation in the runtime.

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit `READYTORUN_FLAG_SkipTypeValidation`. This change: - removes the invalid variance check for type-owned generic constraints - aligns interface method signature validation with the VM by checking all instance methods and virtual methods, including static virtual and static abstract declarations - adds a ReadyToRun regression test based on the reported constraint pattern Fixesdotnet#132724 > [!NOTE] > This pull request was created with GitHub Copilot. (cherry picked from commit 65c1f69)

azure-pipelines · 2026-09-02T18:27:22Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-09-02T18:28:01Z

Tagging subscribers to this area: @dotnet/crossgen-contrib
See info in area-owners.md if you want to be subscribed.

Copilot

🟢 Approval recommended

The changes are narrowly scoped to the intended validation logic and align the checks with the stated ECMA/VM behavior without introducing new observable failure paths in the modified regions.

Pull request overview

Backports a Crossgen2 type-validation fix to release/10.0 so valid variant interfaces with type-owned generic constraints no longer fail variance validation (and thus can retain READYTORUN_FLAG_SkipTypeValidation for the intended perf optimization).

Changes:

Expands interface method signature variance validation to cover all instance methods and all virtual methods (including static abstract/static virtual interface members).
Removes the incorrect variance validation applied to a generic type’s own generic parameter constraints (per ECMA-335 II.9.7).

File summaries

File	Description
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/TypeValidationChecker.cs	Fixes Crossgen2 variance validation rules for type-owned constraints and broadens interface method signature checking to match VM behavior.

Review details

Files reviewed: 1/1 changed files
Comments generated: 0
Review effort level: Lite

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JulieLeeMSFT · 2026-09-03T18:42:47Z

/ba-g unrelated known issues.

jtschuster · 2026-09-02T18:26:40Z

Backport of #132809 to release/10.0

Customer Impact

Customer reported
Found internally

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit READYTORUN_FLAG_SkipTypeValidation, disabling the perf optimization.

This change:

removes the invalid variance check for type-owned generic constraints
aligns interface method signature validation with the VM by checking all instance methods and - virtual methods, including static virtual and static abstract declarations
adds a ReadyToRun regression test based on the reported constraint pattern

Fixes#132724

Regression

Yes.
No
Reduce types loaded on startup significantly #120459 introduced the regression.

Testing

Testing was done on main and release/11.0-rc1. release/10.0 does not have the test project that the test was added to. The test project was manually built locally and contained the expected READYTORUN_FLAG_SkipTypeValidation flag.

Risk

Low. The change makes the validation match the ECMA spec and matches the validation in the runtime.

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit `READYTORUN_FLAG_SkipTypeValidation`. This change: - removes the invalid variance check for type-owned generic constraints - aligns interface method signature validation with the VM by checking all instance methods and virtual methods, including static virtual and static abstract declarations - adds a ReadyToRun regression test based on the reported constraint pattern Fixesdotnet#132724 > [!NOTE] > This pull request was created with GitHub Copilot. (cherry picked from commit 65c1f69)

azure-pipelines · 2026-09-02T18:27:22Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-09-02T18:28:01Z

Tagging subscribers to this area: @dotnet/crossgen-contrib
See info in area-owners.md if you want to be subscribed.

Copilot

🟢 Approval recommended

The changes are narrowly scoped to the intended validation logic and align the checks with the stated ECMA/VM behavior without introducing new observable failure paths in the modified regions.

Pull request overview

Backports a Crossgen2 type-validation fix to release/10.0 so valid variant interfaces with type-owned generic constraints no longer fail variance validation (and thus can retain READYTORUN_FLAG_SkipTypeValidation for the intended perf optimization).

Changes:

Expands interface method signature variance validation to cover all instance methods and all virtual methods (including static abstract/static virtual interface members).
Removes the incorrect variance validation applied to a generic type’s own generic parameter constraints (per ECMA-335 II.9.7).

File summaries

File	Description
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/TypeValidationChecker.cs	Fixes Crossgen2 variance validation rules for type-owned constraints and broadens interface method signature checking to match VM behavior.

Review details

Files reviewed: 1/1 changed files
Comments generated: 0
Review effort level: Lite

💡 Add a code-review agent skill for context-aware, tailored reviews. Learn more in the docs.

JulieLeeMSFT · 2026-09-03T18:42:47Z

/ba-g unrelated known issues.

jtschuster · 2026-09-02T18:26:40Z

Backport of #132809 to release/10.0

Customer Impact

Customer reported
Found internally

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit READYTORUN_FLAG_SkipTypeValidation, disabling the perf optimization.

This change:

removes the invalid variance check for type-owned generic constraints
aligns interface method signature validation with the VM by checking all instance methods and - virtual methods, including static virtual and static abstract declarations
adds a ReadyToRun regression test based on the reported constraint pattern

Fixes#132724

Regression

Yes.
No
Reduce types loaded on startup significantly #120459 introduced the regression.

Testing

Testing was done on main and release/11.0-rc1. release/10.0 does not have the test project that the test was added to. The test project was manually built locally and contained the expected READYTORUN_FLAG_SkipTypeValidation flag.

Risk

Low. The change makes the validation match the ECMA spec and matches the validation in the runtime.

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit `READYTORUN_FLAG_SkipTypeValidation`. This change: - removes the invalid variance check for type-owned generic constraints - aligns interface method signature validation with the VM by checking all instance methods and virtual methods, including static virtual and static abstract declarations - adds a ReadyToRun regression test based on the reported constraint pattern Fixesdotnet#132724 > [!NOTE] > This pull request was created with GitHub Copilot. (cherry picked from commit 65c1f69)

azure-pipelines · 2026-09-02T18:27:22Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-09-02T18:28:01Z

Tagging subscribers to this area: @dotnet/crossgen-contrib
See info in area-owners.md if you want to be subscribed.

Copilot

🟢 Approval recommended

The changes are narrowly scoped to the intended validation logic and align the checks with the stated ECMA/VM behavior without introducing new observable failure paths in the modified regions.

Pull request overview

Backports a Crossgen2 type-validation fix to release/10.0 so valid variant interfaces with type-owned generic constraints no longer fail variance validation (and thus can retain READYTORUN_FLAG_SkipTypeValidation for the intended perf optimization).

Changes:

Expands interface method signature variance validation to cover all instance methods and all virtual methods (including static abstract/static virtual interface members).
Removes the incorrect variance validation applied to a generic type’s own generic parameter constraints (per ECMA-335 II.9.7).

File summaries

File	Description
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/TypeValidationChecker.cs	Fixes Crossgen2 variance validation rules for type-owned constraints and broadens interface method signature checking to match VM behavior.

Review details

Files reviewed: 1/1 changed files
Comments generated: 0
Review effort level: Lite

💡 Add a code-review agent skill for context-aware, tailored reviews. Learn more in the docs.

JulieLeeMSFT · 2026-09-03T18:42:47Z

/ba-g unrelated known issues.

jtschuster · 2026-09-02T18:26:40Z

Backport of #132809 to release/10.0

Customer Impact

Customer reported
Found internally

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit READYTORUN_FLAG_SkipTypeValidation, disabling the perf optimization.

This change:

removes the invalid variance check for type-owned generic constraints
aligns interface method signature validation with the VM by checking all instance methods and - virtual methods, including static virtual and static abstract declarations
adds a ReadyToRun regression test based on the reported constraint pattern

Fixes#132724

Regression

Yes.
No
Reduce types loaded on startup significantly #120459 introduced the regression.

Testing

Testing was done on main and release/11.0-rc1. release/10.0 does not have the test project that the test was added to. The test project was manually built locally and contained the expected READYTORUN_FLAG_SkipTypeValidation flag.

Risk

Low. The change makes the validation match the ECMA spec and matches the validation in the runtime.

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit `READYTORUN_FLAG_SkipTypeValidation`. This change: - removes the invalid variance check for type-owned generic constraints - aligns interface method signature validation with the VM by checking all instance methods and virtual methods, including static virtual and static abstract declarations - adds a ReadyToRun regression test based on the reported constraint pattern Fixesdotnet#132724 > [!NOTE] > This pull request was created with GitHub Copilot. (cherry picked from commit 65c1f69)

azure-pipelines · 2026-09-02T18:27:22Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-09-02T18:28:01Z

Tagging subscribers to this area: @dotnet/crossgen-contrib
See info in area-owners.md if you want to be subscribed.

Copilot

🟢 Approval recommended

The changes are narrowly scoped to the intended validation logic and align the checks with the stated ECMA/VM behavior without introducing new observable failure paths in the modified regions.

Pull request overview

Backports a Crossgen2 type-validation fix to release/10.0 so valid variant interfaces with type-owned generic constraints no longer fail variance validation (and thus can retain READYTORUN_FLAG_SkipTypeValidation for the intended perf optimization).

Changes:

Expands interface method signature variance validation to cover all instance methods and all virtual methods (including static abstract/static virtual interface members).
Removes the incorrect variance validation applied to a generic type’s own generic parameter constraints (per ECMA-335 II.9.7).

File summaries

File	Description
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/TypeValidationChecker.cs	Fixes Crossgen2 variance validation rules for type-owned constraints and broadens interface method signature checking to match VM behavior.

Review details

Files reviewed: 1/1 changed files
Comments generated: 0
Review effort level: Lite

💡 Add a code-review agent skill for context-aware, tailored reviews. Learn more in the docs.

JulieLeeMSFT · 2026-09-03T18:42:47Z

/ba-g unrelated known issues.

jtschuster · 2026-09-02T18:26:40Z

Backport of #132809 to release/10.0

Customer Impact

Customer reported
Found internally

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit READYTORUN_FLAG_SkipTypeValidation, disabling the perf optimization.

This change:

removes the invalid variance check for type-owned generic constraints
aligns interface method signature validation with the VM by checking all instance methods and - virtual methods, including static virtual and static abstract declarations
adds a ReadyToRun regression test based on the reported constraint pattern

Fixes#132724

Regression

Yes.
No
Reduce types loaded on startup significantly #120459 introduced the regression.

Testing

Testing was done on main and release/11.0-rc1. release/10.0 does not have the test project that the test was added to. The test project was manually built locally and contained the expected READYTORUN_FLAG_SkipTypeValidation flag.

Risk

Low. The change makes the validation match the ECMA spec and matches the validation in the runtime.

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit `READYTORUN_FLAG_SkipTypeValidation`. This change: - removes the invalid variance check for type-owned generic constraints - aligns interface method signature validation with the VM by checking all instance methods and virtual methods, including static virtual and static abstract declarations - adds a ReadyToRun regression test based on the reported constraint pattern Fixesdotnet#132724 > [!NOTE] > This pull request was created with GitHub Copilot. (cherry picked from commit 65c1f69)

azure-pipelines · 2026-09-02T18:27:22Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-09-02T18:28:01Z

Tagging subscribers to this area: @dotnet/crossgen-contrib
See info in area-owners.md if you want to be subscribed.

Copilot

🟢 Approval recommended

The changes are narrowly scoped to the intended validation logic and align the checks with the stated ECMA/VM behavior without introducing new observable failure paths in the modified regions.

Pull request overview

Backports a Crossgen2 type-validation fix to release/10.0 so valid variant interfaces with type-owned generic constraints no longer fail variance validation (and thus can retain READYTORUN_FLAG_SkipTypeValidation for the intended perf optimization).

Changes:

Expands interface method signature variance validation to cover all instance methods and all virtual methods (including static abstract/static virtual interface members).
Removes the incorrect variance validation applied to a generic type’s own generic parameter constraints (per ECMA-335 II.9.7).

File summaries

File	Description
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/TypeValidationChecker.cs	Fixes Crossgen2 variance validation rules for type-owned constraints and broadens interface method signature checking to match VM behavior.

Review details

Files reviewed: 1/1 changed files
Comments generated: 0
Review effort level: Lite

💡 Add a code-review agent skill for context-aware, tailored reviews. Learn more in the docs.

JulieLeeMSFT · 2026-09-03T18:42:47Z

/ba-g unrelated known issues.

jtschuster · 2026-09-02T18:26:40Z

Backport of #132809 to release/10.0

Customer Impact

Customer reported
Found internally

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit READYTORUN_FLAG_SkipTypeValidation, disabling the perf optimization.

This change:

removes the invalid variance check for type-owned generic constraints
aligns interface method signature validation with the VM by checking all instance methods and - virtual methods, including static virtual and static abstract declarations
adds a ReadyToRun regression test based on the reported constraint pattern

Fixes#132724

Regression

Yes.
No
Reduce types loaded on startup significantly #120459 introduced the regression.

Testing

Testing was done on main and release/11.0-rc1. release/10.0 does not have the test project that the test was added to. The test project was manually built locally and contained the expected READYTORUN_FLAG_SkipTypeValidation flag.

Risk

Low. The change makes the validation match the ECMA spec and matches the validation in the runtime.

Crossgen2 applied method generic-constraint variance rules to a generic type's own constraints. ECMA-335 II.9.7 explicitly leaves type-owned constraints unrestricted, so valid variant interfaces could fail automatic validation and omit `READYTORUN_FLAG_SkipTypeValidation`. This change: - removes the invalid variance check for type-owned generic constraints - aligns interface method signature validation with the VM by checking all instance methods and virtual methods, including static virtual and static abstract declarations - adds a ReadyToRun regression test based on the reported constraint pattern Fixesdotnet#132724 > [!NOTE] > This pull request was created with GitHub Copilot. (cherry picked from commit 65c1f69)

azure-pipelines · 2026-09-02T18:27:22Z

Azure Pipelines: Successfully started running 3 pipeline(s). 13 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

dotnet-policy-service · 2026-09-02T18:28:01Z

Tagging subscribers to this area: @dotnet/crossgen-contrib
See info in area-owners.md if you want to be subscribed.

Copilot

🟢 Approval recommended

The changes are narrowly scoped to the intended validation logic and align the checks with the stated ECMA/VM behavior without introducing new observable failure paths in the modified regions.

Pull request overview

Backports a Crossgen2 type-validation fix to release/10.0 so valid variant interfaces with type-owned generic constraints no longer fail variance validation (and thus can retain READYTORUN_FLAG_SkipTypeValidation for the intended perf optimization).

Changes:

Expands interface method signature variance validation to cover all instance methods and all virtual methods (including static abstract/static virtual interface members).
Removes the incorrect variance validation applied to a generic type’s own generic parameter constraints (per ECMA-335 II.9.7).

File summaries

File	Description
src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/TypeValidationChecker.cs	Fixes Crossgen2 variance validation rules for type-owned constraints and broadens interface method signature checking to match VM behavior.

Review details

Files reviewed: 1/1 changed files
Comments generated: 0
Review effort level: Lite

💡 Add a code-review agent skill for context-aware, tailored reviews. Learn more in the docs.

JulieLeeMSFT · 2026-09-03T18:42:47Z

/ba-g unrelated known issues.

jtschuster added this to the 10.0.x milestone Sep 2, 2026

jtschuster requested review from agocke, davidwrighton and jkoritzinsky September 2, 2026 18:26

jtschuster self-assigned this Sep 2, 2026

CopilotAI lite review requested due to automatic review settings September 2, 2026 18:26

jtschuster added the Servicing-consider Issue for next servicing release review label Sep 2, 2026

jtschuster added this to AppModel Sep 2, 2026

github-actionsBot added the area-ReadyToRun label Sep 2, 2026

Copilotstarted reviewing on behalf of jtschuster September 2, 2026 18:27 View session

CopilotAI reviewed Sep 2, 2026
View reviewed changes

This was referenced Sep 3, 2026
System.Net.Tests.InvalidClientRequestTests.GetContext_InvalidRequest_DoesNotGetContext times out #132336
Closed
[Test Failure] Authentication failed: Status code: QUIC_STATUS_TLS_ERROR when SNI is missing or IP literal #133096
Closed

JulieLeeMSFT added Servicing-approved Approved for servicing release and removed Servicing-consider Issue for next servicing release review labels Sep 3, 2026

jtschuster added this to the 10.0.x milestone Sep 2, 2026

jtschuster requested review from agocke, davidwrighton and jkoritzinsky September 2, 2026 18:26

jtschuster self-assigned this Sep 2, 2026

CopilotAI lite review requested due to automatic review settings September 2, 2026 18:26

jtschuster added the Servicing-consider Issue for next servicing release review label Sep 2, 2026

jtschuster added this to AppModel Sep 2, 2026

github-actionsBot added the area-ReadyToRun label Sep 2, 2026

Copilotstarted reviewing on behalf of jtschuster September 2, 2026 18:27 View session

CopilotAI reviewed Sep 2, 2026
View reviewed changes

This was referenced Sep 3, 2026
System.Net.Tests.InvalidClientRequestTests.GetContext_InvalidRequest_DoesNotGetContext times out #132336
Closed
[Test Failure] Authentication failed: Status code: QUIC_STATUS_TLS_ERROR when SNI is missing or IP literal #133096
Closed

JulieLeeMSFT added Servicing-approved Approved for servicing release and removed Servicing-consider Issue for next servicing release review labels Sep 3, 2026

jtschuster added this to the 10.0.x milestone Sep 2, 2026

jtschuster requested review from agocke, davidwrighton and jkoritzinsky September 2, 2026 18:26

jtschuster self-assigned this Sep 2, 2026

CopilotAI lite review requested due to automatic review settings September 2, 2026 18:26

jtschuster added the Servicing-consider Issue for next servicing release review label Sep 2, 2026

jtschuster added this to AppModel Sep 2, 2026

github-actionsBot added the area-ReadyToRun label Sep 2, 2026

Copilotstarted reviewing on behalf of jtschuster September 2, 2026 18:27 View session

CopilotAI reviewed Sep 2, 2026
View reviewed changes

This was referenced Sep 3, 2026
System.Net.Tests.InvalidClientRequestTests.GetContext_InvalidRequest_DoesNotGetContext times out #132336
Closed
[Test Failure] Authentication failed: Status code: QUIC_STATUS_TLS_ERROR when SNI is missing or IP literal #133096
Closed

JulieLeeMSFT added Servicing-approved Approved for servicing release and removed Servicing-consider Issue for next servicing release review labels Sep 3, 2026

jtschuster added this to the 10.0.x milestone Sep 2, 2026

jtschuster requested review from agocke, davidwrighton and jkoritzinsky September 2, 2026 18:26

jtschuster self-assigned this Sep 2, 2026

CopilotAI lite review requested due to automatic review settings September 2, 2026 18:26

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System.Net.Tests.InvalidClientRequestTests.GetContext_InvalidRequest_DoesNotGetContext times out #132336
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[Test Failure] Authentication failed: Status code: QUIC_STATUS_TLS_ERROR when SNI is missing or IP literal #133096
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System.Net.Tests.InvalidClientRequestTests.GetContext_InvalidRequest_DoesNotGetContext times out #132336
Closed
[Test Failure] Authentication failed: Status code: QUIC_STATUS_TLS_ERROR when SNI is missing or IP literal #133096
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JulieLeeMSFT added Servicing-approved Approved for servicing release and removed Servicing-consider Issue for next servicing release review labels Sep 3, 2026

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System.Net.Tests.InvalidClientRequestTests.GetContext_InvalidRequest_DoesNotGetContext times out #132336
Closed
[Test Failure] Authentication failed: Status code: QUIC_STATUS_TLS_ERROR when SNI is missing or IP literal #133096
Closed

JulieLeeMSFT added Servicing-approved Approved for servicing release and removed Servicing-consider Issue for next servicing release review labels Sep 3, 2026

jtschuster added this to the 10.0.x milestone Sep 2, 2026

jtschuster requested review from agocke, davidwrighton and jkoritzinsky September 2, 2026 18:26

jtschuster self-assigned this Sep 2, 2026

CopilotAI lite review requested due to automatic review settings September 2, 2026 18:26

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This was referenced Sep 3, 2026
System.Net.Tests.InvalidClientRequestTests.GetContext_InvalidRequest_DoesNotGetContext times out #132336
Closed
[Test Failure] Authentication failed: Status code: QUIC_STATUS_TLS_ERROR when SNI is missing or IP literal #133096
Closed

JulieLeeMSFT added Servicing-approved Approved for servicing release and removed Servicing-consider Issue for next servicing release review labels Sep 3, 2026

jtschuster added this to the 10.0.x milestone Sep 2, 2026

jtschuster requested review from agocke, davidwrighton and jkoritzinsky September 2, 2026 18:26

jtschuster self-assigned this Sep 2, 2026

CopilotAI lite review requested due to automatic review settings September 2, 2026 18:26

jtschuster added the Servicing-consider Issue for next servicing release review label Sep 2, 2026

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This was referenced Sep 3, 2026
System.Net.Tests.InvalidClientRequestTests.GetContext_InvalidRequest_DoesNotGetContext times out #132336
Closed
[Test Failure] Authentication failed: Status code: QUIC_STATUS_TLS_ERROR when SNI is missing or IP literal #133096
Closed

JulieLeeMSFT added Servicing-approved Approved for servicing release and removed Servicing-consider Issue for next servicing release review labels Sep 3, 2026

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