This is another reason why macros should not be treated or even viewed as source transformation passes. There is information loss involved in that. There's no reason the compiler shouldn't be able to only warn in the absence of a macro expansion.
The compiler passes of both GCC and Clang are aware of macro expansions since they are able to tell you about errors which occur after a macro expansion, i.e. the error messages similar to "... in expansion of macro X ...".
Yeah I'm aware. I'm more referring to the comments here, where people use "this is generated by a macro" as a justification even though that only makes sense if you think of preprocessed code as a separate stage from the actual code, which I'm arguing you shouldn't. That said though, I'm surprised they don't treat it that way for other cases like these?
Sometimes you might care about differing macros that expand to the same thing in a case like this example. The key point is the compiler can't read your mind to know when those cases are.
