Add DynamicallyAccessedMembers attributes to UIsInstT methods in variance tests

[Copilot]

Fixes Issue

main PR

Description

Added [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)] attribute to the U type parameter in the UIsInstT<T,U> method across six variance test files (IsInst001.cs through IsInst006.cs) under src/tests/Loader/classloader/generics/Variance/IL.

This annotation is required because the method calls Activator.CreateInstance(typeof(U)), which needs the type to have a public parameterless constructor. Without this attribute, the trimmer removes the constructor when building with TrimMode=full, causing test failures.

Also added the required using System.Diagnostics.CodeAnalysis; namespace to all six files.

Customer Impact

Ensures proper test coverage for trimming scenarios. Without these attributes, variance tests would fail when built with TrimMode=full, reducing our confidence in the trimming behavior of variance-related functionality.

Regression

Not applicable - this is new work for trimming compatibility to enable building the test tree with TrimMode=full.

Testing

• Changes follow the same pattern as previous work on UnboxUToTInternal methods
• Modified files compile successfully
• No security vulnerabilities detected by CodeQL

Risk

Low - changes only add trimming annotations to test code without altering test logic or functionality.

Package authoring no longer needed in .NET 9

IMPORTANT: Starting with .NET 9, you no longer need to edit a NuGet package's csproj to enable building and bump the version.
Keep in mind that we still need package authoring in .NET 8 and older versions.

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[MichalStrehovsky]

@copilot for C# source files under src/tests/Loader/classloader/generics/Variance/IL, find the following method in each of the files: public static bool UIsInstT<T,U>(bool expected). Add an attribute like this: public static bool UIsInstT<T, [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)] U>(bool expected). The namespace of the attribute is System.Diagnostics.CodeAnalysis.

[MichalStrehovsky]

@copilot for C# source files under src/tests/Loader/classloader/generics/Variance/IL, find the following method in each of the files: public static bool UIsInstT<T,U>(bool expected). Add an attribute like this: public static bool UIsInstT<T, [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)] U>(bool expected). The namespace of the attribute is System.Diagnostics.CodeAnalysis.

[Copilot]

@copilot for C# source files under src/tests/Loader/classloader/generics/Variance/IL, find the following method in each of the files: public static bool UIsInstT<T,U>(bool expected). Add an attribute ...

Completed - see commit bfd0090.

@copilot for C# source files under src/tests/Loader/classloader/generics/Variance/IL, find the following method in each of the files: public static bool UIsInstT<T,U>(bool expected). Add an attribute ...

Added [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)] attribute to the U type parameter in the UIsInstT<T,U> method across all six IsInst test files (IsInst001-006.cs). Also added the required using System.Diagnostics.CodeAnalysis; namespace. Changes committed in bfd0090.