Fall back to MethodTable when generic type resolution produces a placeholder#1416
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max-charlamb merged 1 commit intomicrosoft:mainfrom Apr 10, 2026
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…eholder When __Canon filtering (introduced in microsoft#1373) nulls a field's type and the metadata signature fallback resolves to a ClrGenericType placeholder (e.g. 'TStateMachine' with no fields), fall back to resolving via the field's MethodTable directly. This handles compiler-generated types nested inside open generic classes (e.g. async state machines in local functions) where GetTypeByName fails because it compares closed-generic names against open-generic TypeDefs. The MethodTable resolves to __Canon, which restores the pre-microsoft#1373 behavior: the field reports IsObjectReference=true, so consumers use ReadObjectField to get the concrete type from the heap. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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leculver
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Apr 10, 2026
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When
__Canonfiltering (introduced in #1373) nulls a field's type and the metadata signature fallback resolves to a ClrGenericType placeholder (e.g.TStateMachinewith no fields), fall back to resolving via the field's MethodTable directly.This handles compiler-generated types nested inside open generic classes (e.g. async state machines in local functions) where GetTypeByName fails because it compares closed-generic names against open-generic TypeDefs.
The MethodTable resolves to __Canon, which restores the pre-#1373 behavior: the field reports IsObjectReference=true, so consumers use ReadObjectField to get the concrete type from the heap.