Placing DAM on a Type array crashes illink

[MichalStrehovsky]

dotnet/BenchmarkDotNet#1960 (comment)

[2022/03/28 17:20:11][INFO]   Unhandled exception. System.InvalidOperationException: Operation is not valid due to the current state of the object.
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Dataflow.ReflectionMethodBodyScanner.GetValueNodeForCustomAttributeArgument(CustomAttributeArgument argument)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Dataflow.ReflectionMethodBodyScanner.ProcessAttributeDataflow(MethodDefinition method, IList`1 arguments)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkCustomAttributeArguments(CustomAttribute ca)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkCustomAttribute(CustomAttribute ca, DependencyInfo& reason)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkCustomAttributes(ICustomAttributeProvider provider, DependencyInfo& reason)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkEntireType(TypeDefinition type, DependencyInfo& reason)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkEntireAssembly(AssemblyDefinition assembly)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkAssembly(AssemblyDefinition assembly, DependencyInfo reason)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkModule(ModuleDefinition module, DependencyInfo reason)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkType(TypeReference reference, DependencyInfo reason, Nullable`1 origin)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkType(TypeReference reference, DependencyInfo reason, Nullable`1 origin)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkType(TypeReference reference, DependencyInfo reason, Nullable`1 origin)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkField(FieldDefinition field, DependencyInfo& reason)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkEntireType(TypeDefinition type, DependencyInfo& reason)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkEntireType(TypeDefinition type, DependencyInfo& reason)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkEntireAssembly(AssemblyDefinition assembly)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkAssembly(AssemblyDefinition assembly, DependencyInfo reason)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.MarkModule(ModuleDefinition module, DependencyInfo reason)
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.ProcessMarkedPending()
[2022/03/28 17:20:11][INFO]      at Mono.Linker.Steps.MarkStep.Initialize()

I think the bug is here:

https://github.com/dotnet/linker/blob/da3c743a606b300c245c312c8cd9b3238d110d65/src/linker/Linker.Dataflow/FlowAnnotations.cs#L441-L450

This falls into the Cecil footgun that resolving the type removes any signs of it ever being a constructed/parameterized type.

[dotnet-policy-service]

Tagging subscribers to this area: @agocke, @sbomer, @vitek-karas
See info in area-owners.md if you want to be subscribed.