> Is that behaviour documented somewhere I missed? Sadly, no. Actually, none of the diagnostic calls are documented. The prototypes are even in toplev.h instead of diagnostic.h, between "fatal_insn_not_found() and "rest_of_decl_compilation()". It's quite haphazard.
The diagnostic_info structure does have this comment: /* Which OPT_* directly controls this diagnostic. */ int option_index; The word "controls" implies, well, control. But I don't think that counts as the kind of documentation you're thinking about.
