The ILLink Roslyn Analyzer has some logic to handle dynamic object invocations, producing RequiresUnreferencedCode warnings, for example:

dynamic s = "hello";
s.DoSomething();

This produces IL2026 at the callsite.

This compiles into something like the following:

        object arg = "hello";
        if (<>o__0.<>p__0 == null)
        {
            Type typeFromHandle = typeof(C);
            CSharpArgumentInfo[] array = new CSharpArgumentInfo[1];
            array[0] = CSharpArgumentInfo.Create(CSharpArgumentInfoFlags.None, null);
            <>o__0.<>p__0 = CallSite<Action<CallSite, object>>.Create(Microsoft.CSharp.RuntimeBinder.Binder.InvokeMember(CSharpBinderFlags.ResultDiscarded, "DoSomething", null, typeFromHandle, array));
        }
        <>o__0.<>p__0.Target(<>o__0.<>p__0, arg);

ILLink also produces IL2026 due to InvokeMember being annotated with RequiresUnreferencedCode.

ILCompiler additionaly produces IL3050 due to CallSite.Create being annotated with RequiresDynamicCode. We should consider ways to produce the same warning in the ILLink Roslyn analyzer.

#94236 is improving the analyzer's coverage of the RequiresUnreferencedCode warnings by treating dynamic invocations as calls to RuntimeBinder methods. Perhaps we could do the same by including an additional call to CallSite.Create.