https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89072
--- Comment #12 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> --- (In reply to Segher Boessenkool from comment #11) > Sure. If people want the pain, they can have it. But it is never okay to > cause other people to have -Werror -- they may have a different compiler > (version) that no one else has tested with, they may have different warnings > enabled, etc. For MPFR automated tests (and sometimes during my usual development too), I use -Werror in combination with -Wall plus some other useful warnings (-Wold-style-declaration -Wold-style-definition -Wmissing-parameter-type -Wmissing-prototypes -Wmissing-declarations -Wmissing-field-initializers -Wc++-compat -Wwrite-strings -Wcast-function-type -Wcast-align=strict -Wimplicit-fallthrough), and this is very useful, though this sometimes triggers GCC bugs. But of course, it's for internal use only. And the use of -Werror without "=" is valid only because I make sure that no other -W... options are used.