// PROTOTYPE(NullableReferenceTypes): We should warn on the first 3 ToString calls.
comp.VerifyDiagnostics(
// (19,9): error CS0411: The type arguments for method 'C.CopyOutInherit<T1, T2>(T1, out T2)' cannot be inferred from the usage. Try specifying the type arguments explicitly.
// CopyOutInherit(u, out var x4);
Diagnostic(ErrorCode.ERR_CantInferMethTypeArgs, "CopyOutInherit").WithArguments("C.CopyOutInherit<T1, T2>(T1, out T2)").WithLocation(19, 9)
// (29,9): error CS0411: The type arguments for method 'C.CopyOutInherit<T1, T2>(T1, out T2)' cannot be inferred from the usage. Try specifying the type arguments explicitly.
// CopyOutInherit(u, out var x7);
Diagnostic(ErrorCode.ERR_CantInferMethTypeArgs, "CopyOutInherit").WithArguments("C.CopyOutInherit<T1, T2>(T1, out T2)").WithLocation(29, 9)