[acdha]

> Don't C compilers warn about code that is never executed?

Not by default. On both GCC and Clang this kind of error isn't caught using -Wall or even -Wextra - you have to explicitly opt-in using -Wunreachable-code. It'd really be nice if that changed and Clang basically had close to -Weverything on by default and required you to opt out, preferably with something like `#pragma ALLOW_SHODDY_<category>` per file to put some pressure on C programmers not to just continue ignoring errors rather than fixing them.

[gsnedders]

In the latest GCC releases, -Wunreachable-code has been removed (the option still exists but is silently ignored for compat with existing Makefiles), as its output varied so much between releases (depending on what got optimized away).

[acdha]

I'd hope after this someone brings it back in some form – it's an incredibly useful tool and a diversity of implementations would be great for security-critical code.