Implement IsByRefLike on the remaining Reflection.Emit Type subclasses

[caraioniurie47]

Fixes #91532

Type.IsByRefLike threw NotSupportedException: Derived classes must provide an implementation. for four Reflection.Emit types. #34846 added the override to the runtime builder classes.

Type	Obtained from	IsByRefLike now
SymbolType	MakeArrayType, MakePointerType, MakeByRefType on a TypeBuilder	false
TypeBuilderInstantiation	MakeGenericType on a TypeBuilder, or MakeGenericType on a runtime generic type with a builder argument	the generic type definition's value
TypeBuilderImpl	DefineType on a PersistedAssemblyBuilder module	false
GenericTypeParameterBuilderImpl	DefineGenericParameters on a PersistedAssemblyBuilder type	false

TypeBuilderInstantiation forwards instead of returning false. A runtime generic definition instantiated over a builder also produces one (RuntimeType.CoreCLR.cs:3600, RuntimeType.Mono.cs:1460), so typeof(Span<>).MakeGenericType(typeBuilder) is a TypeBuilderInstantiation over Span<> and is by-ref-like. Forwarding matches SignatureConstructedGenericType.IsByRefLike. When the definition is itself a builder, the result is false.

The persisted builder types are a separate commit. In the issue, buyaa-n suggested leaving TypeBuilderImpl and GenericTypeParameterBuilderImpl out as incomplete and not yet public. PersistedAssemblyBuilder is public now and both throw the same way, so they are included; if they should still stay out, the second commit can be dropped, though MakeGenericType on a persisted TypeBuilder then still throws, because TypeBuilderInstantiation forwards to it.

The observable change is that these getters return a value where they threw NotSupportedException.

Tests

New cases in TypeBuilderIsByRefLike.cs (runtime builders) and AssemblySaveTypeBuilderAPIsTests.cs (persisted builders) cover the persisted builder and its generic parameter, MakeGenericType on a builder, and MakeArrayType, MakePointerType and MakeByRefType on a builder and its generic parameter, plus Span<>, ReadOnlySpan<> and List<> instantiated over a builder. The 8 new test cases failed before the fix and pass with it.

Run locally on Windows x64:

• System.Reflection.Emit.Tests: all pass on a clr+libs -rc checked build and on a clr+libs -rc release -lc release build.
• System.Linq.Expressions.Tests (Release runtime only): all pass.
• On the checked build, other library test projects that use Reflection.Emit builders or IsByRefLike, among them System.Runtime.Tests, System.Reflection.Tests, System.Reflection.Emit.ILGeneration.Tests, System.Reflection.DispatchProxy.Tests and System.Reflection.MetadataLoadContext.Tests: all pass except XmlSystemPathResolverTests.TestResolveInvalidPath in System.Private.Xml.Tests, which needs notfound.invalid.corp.microsoft.com not to resolve, and my network's DNS returns an address for it.

Not run locally: Mono and NativeAOT.

Not in this PR

System.Reflection.Context has the same gap: types mapped by a CustomReflectionContext throw from IsByRefLike and three other Type members. That is #133816.

Note

AI-generated, written at my direction and reviewed by me before posting. The test results are from local builds of this branch on Windows x64, on the configurations named above; that the new tests fail without the fix was checked on a checked build without the product change.

[azure-pipelines]

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]

Tagging subscribers to this area: @steveisok, @dotnet/area-system-reflection
See info in area-owners.md if you want to be subscribed.

[caraioniurie47]

@dotnet-policy-service agree

[azure-pipelines]

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.

[caraioniurie47]

CI: none of the failed tests is in Reflection.Emit, and System.Reflection.Emit.Tests, System.Runtime.Tests and System.Linq.Expressions.Tests passed on every leg that runs them. The two failures Build Analysis does not match predate this PR:

• github60486 on mono linux x64 Release (Expected "GetCurrentMethodInlineable", Actual "ValidateCurrentMethod") started failing after [wasm] Fix caller identification across R2R prestub transitions #133707 added those assertions, and fails the same way on other PRs' builds, including those for JIT: Fix loop cloning with nested EH regions #133790 and Align CompositeFormat index and width limits with string.Format #133800. Fix github60486 AOT caller identity and frame enumeration #133775 describes it as one of the two failures it fixes; github60486 failed with NRE at Program.ValidateRecursiveCurrentMethod(Int32 depth) #133798's match pattern covers only the other one.
• tracing/runtimeeventsource/nativeruntimeeventsource on mono windows x64 Release (Debug.Assert errorCode != Interop.Errors.ERROR_SUCCESS from Console.set_ForegroundColor) failed with the same assert and stack on build 1585713 for JIT: guard negative-offset bounds inference against underflow #133272. Over the last 7 days of test history it failed in 2 of 404 results, across all legs.

Note

AI-generated, written at my direction and reviewed by me before posting. The results are from Azure DevOps build 1594658 on commit e327094, and from Azure DevOps test results and test history for other dotnet/runtime PR builds, read through the Azure DevOps and Helix APIs.

[caraioniurie47]

@jkotas #134371, which fixed the same IsByRefLike exception for System.Reflection.Context types, has merged. Could you take a look at this one when you have time? Thanks!

[Copilot]

Copilot review overview

🟢 Approval recommended

The implementations match established sibling-type behavior and the tests cover all affected subclasses.

Review effort: Balanced
Findings: None

What changed in this PR

Completes Type.IsByRefLike support across remaining Reflection.Emit type implementations, replacing inherited exceptions with consistent values.

Changes:

• Returns false for builder, generic-parameter, and compound symbol types.
• Forwards constructed generic types to their generic definition.
• Adds regression coverage for runtime and persisted builders.

File	Description
TypeBuilderIsByRefLike.cs	Tests runtime builder-derived types.
AssemblySaveTypeBuilderAPIsTests.cs	Tests persisted builder types.
TypeBuilderImpl.cs	Returns false for persisted builders.
GenericTypeParameterBuilderImpl.cs	Returns false for persisted generic parameters.
TypeBuilderInstantiation.cs	Forwards to the generic definition.
SymbolType.cs	Returns false for compound types.

[jkotas]

Thanks