Stripping parameter names for members accessed by DAM.All

[sbomer]

Marking types for DynamicallyAccessedMembers.All or NestedTypes is stripping metadata for the accessed members (the repro requires the assembly to be trimmed, for example with <TrimmerDefaultAction>link</TrimmerDefaultAction>):

using System;
using System.Diagnostics.CodeAnalysis;
using DAM = System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute;
using RUC = System.Diagnostics.CodeAnalysis.RequiresUnreferencedCodeAttribute;

public class Program {
	public static void Main() => RequireAll(typeof(Foo));

	static void RequireAll([DAM(DynamicallyAccessedMemberTypes.All)] Type t) {
		t.GetMethod("Method").Invoke (null, new object[] { "Hi" });
	}
}

public class Foo {
	public static void Method(string message) {
		throw new Exception(message);
	}
}

dotnet run (notice Foo.Method has the parameter name kept):

Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.Exception: Hi
   at Foo.Method(String message) in /home/sven/tmp/damt/th2/Program.cs:line 17
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Span`1& arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) in System.Private.CoreLib.dll:token 0x6004db0+0x23
   at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters) in System.Private.CoreLib.dll:token 0x6004cb4+0x0
   at Program.RequireAll(Type t) in /home/sven/tmp/damt/th2/Program.cs:line 10
   at Program.Main() in /home/sven/tmp/damt/th2/Program.cs:line 7

running a trimmed app (notice Foo.Method is missing the parameter name):

Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.Exception: Hi
   at Foo.Method(String ) in /home/sven/tmp/damt/th2/Program.cs:line 23
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle.InvokeMethod(Object , Span`1& , Signature , Boolean , Boolean )
   at System.Reflection.RuntimeMethodInfo.Invoke(Object , BindingFlags , Binder , Object[] , CultureInfo ) in System.Private.CoreLib.dll:token 0x600201c+0x23
   at System.Reflection.MethodBase.Invoke(Object , Object[] ) in System.Private.CoreLib.dll:token 0x6001f64+0x0
   at Program.RequireAll(Type ) in /home/sven/tmp/damt/th2/Program.cs:line 16
   at Program.Test1() in /home/sven/tmp/damt/th2/Program.cs:line 12
   at Program.Main() in /home/sven/tmp/damt/th2/Program.cs:line 8
Aborted (core dumped)

This happens because we just call MarkEntireType which doesn't mark the members as reflection-accessed like we do elsewhere: https://github.com/mono/linker/blob/6eae01980dc694107bdee0bc723d75a0dd601f0e/src/linker/Linker.Dataflow/ReflectionMethodBodyScanner.cs#L2330