Trim/AOT analyzer missing some ILC warnings

[Sergio0694]

Description

We're in the process of fixing all trim/AOT warnings in CsWinRT, and as of our latest PR we're now down to 0 warnings when building. However, we still get 4 warnings from ILC at publish time. I figured I'd report them in case they're actual trim bugs. Annotations in code seem correct.

Reproduction Steps

Use this test project: MinimalWinRTComponentTest.zip.

The code for CsWinRT we're working on is here: https://github.com/microsoft/CsWinRT/tree/staging/AOT.

Expected behavior

No ILC warnings.

Actual behavior

ILC : Trim analysis warning IL2068: WinRT.Projections.FindCustomHelperTypeMapping(Type,Boolean): 'WinRT.Projections.FindCustomHelperTypeMapping(Type,Boolean)' method return value does not satisfy 'DynamicallyAccessedMemberTypes.PublicMethods', 'DynamicallyAccessedMemberTypes.PublicFields' requirements. The parameter '#ILLink.Shared.TypeSystemProxy.ParameterIndex' of method 'System.Collections.Generic.Dictionary`2<Type,Type>.TryGetValue(Type,Type&)' does not have matching annotations. The source value must declare at least the same requirements as those declared on the target location it is assigned to. [D:\source\MinimalWinRTComponentTest\MinimalWinRTComponentTest\MinimalWinRTComponentTest.csproj]

ILC : Trim analysis warning IL2087: WinRT.ObjectReferenceWithContext`1.<GetCurrentContext>g__CreateForCurrentContext|19_0(IntPtr): 'type' argument does not satisfy 'DynamicallyAccessedMemberTypes.PublicFields' in call to 'WinRT.GuidGenerator.GetIID(Type)'. The generic parameter 'T' of 'WinRT.ObjectReferenceWithContext`1' does not have matching annotations. The source value must declare at least the same requirements as those declared on the target location it is assigned to. [D:\source\MinimalWinRTComponentTest\MinimalWinRTComponentTest\MinimalWinRTComponentTest.csproj]

ILC : Trim analysis warning IL2055: WinRT.TypeNameSupport.<FindTypeByNameCore>g__ResolveGenericType|9_0(Type,Type[],String): Call to 'System.Type.MakeGenericType(Type[])' can not be statically analyzed. It's not possible to guarantee the availability of requirements of the generic type. [D:\source\MinimalWinRTComponentTest\MinimalWinRTComponentTest\MinimalWinRTComponentTest.csproj]

ILC : Trim analysis warning IL2067: WinRT.GuidGenerator.GetSignature(Type): 'type' argument does not satisfy 'DynamicallyAccessedMemberTypes.PublicFields' in call to 'WinRT.GuidGenerator.GetSignature(Type)'. The parameter 'defaultInterface' of method 'WinRT.Projections.TryGetDefaultInterfaceTypeForRuntimeClassType(Type,Type&)' does not have matching annotations. The source value must declare at least the same requirements as those declared on the target location it is assigned to. [D:\source\MinimalWinRTComponentTest\MinimalWinRTComponentTest\MinimalWinRTComponentTest.csproj]

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Tagging subscribers to this area: @agocke, @sbomer, @vitek-karas
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[Sergio0694]

Some thoughts:

• FindCustomHelperTypeMapping feels like should definitely warn in the IDE (we need a suppression).
• CreateForCurrentContext is missing an annotation. Seems like the call being in a local function breaks the analyzer.
• ResolveGenericType is also missing a suppression, the analyzer seems to miss that.
• GetSignature calls are also missing the IL2067 warnings, we're only seeing IL2062 in the IDE.

[agocke]

FYI @jtschuster

[Sergio0694]

Found two more trim analyzer bugs in CsWinRT:

"ILC : Trim analysis warning IL2075: ABI.Microsoft.UI.Xaml.Data.ManagedCustomPropertyProviderVftbl.Do_Abi_GetCustomProperty_0(IntPtr,IntPtr,IntPtr*): 'this' argument does not satisfy 'DynamicallyAccessedMemberTypes.PublicProperties' in call to 'System.Type.GetProperty(String,BindingFlags)'. The return value of method 'System.Object.GetType()' does not have matching annotations. The source value must declare at least the same requirements as those declared on the target location it is assigned to."

Here.

"ILC : Trim analysis warning IL2075: ABI.Microsoft.UI.Xaml.Data.ManagedCustomPropertyProviderVftbl.Do_Abi_GetIndexedProperty_1(IntPtr,IntPtr,Type,IntPtr*): 'this' argument does not satisfy 'DynamicallyAccessedMemberTypes.PublicProperties' in call to 'System.Type.GetProperty(String,BindingFlags,Binder,Type,Type[],ParameterModifier[])'. The return value of method 'System.Object.GetType()' does not have matching annotations. The source value must declare at least the same requirements as those declared on the target location it is assigned to."

Here.

I'm a bit puzzled as to how the analyzer missed these ones 🤔

[Sergio0694]

Found a bit more in microsoft/CsWinRT#1592:

D:\a_work\1\s\src\WinRT.Runtime\Projections.cs(259,25): Trim analysis error IL2055: WinRT.Projections.FindCustomHelperTypeMapping(Type, Boolean): Call to 'System.Type.MakeGenericType(Type[])' can not be statically analyzed. It's not possible to guarantee the availability of requirements of the generic type. [D:\a_work\1\s\src\Tests\FunctionalTests\ClassActivation\ClassActivation.csproj::TargetFramework=net6.0]

Here. Seems to only warn at publish time, but not in the IDE.

D:\a_work\1\s\src\WinRT.Runtime\TypeExtensions.cs(115,17): Trim analysis error IL2057: WinRT.TypeExtensions.g__FindHelperTypeFallback|1_2(Type): Unrecognized value passed to the parameter 'typeName' of method 'System.Type.GetType(String)'. It's not possible to guarantee the availability of the target type. [D:\a_work\1\s\src\Tests\FunctionalTests\ClassActivation\ClassActivation.csproj::TargetFramework=net6.0]

D:\a_work\1\s\src\WinRT.Runtime\TypeExtensions.cs(91,21): Trim analysis error IL2055: WinRT.TypeExtensions.g__GetHelperTypeFromAttribute|1_1(WindowsRuntimeHelperTypeAttribute, Type): Call to 'System.Type.MakeGenericType(Type[])' can not be statically analyzed. It's not possible to guarantee the availability of requirements of the generic type. [D:\a_work\1\s\src\Tests\FunctionalTests\ClassActivation\ClassActivation.csproj::TargetFramework=net6.0]

Same for these two.