https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95177
--- Comment #17 from Roland Illig <roland.illig at gmx dot de> --- (In reply to Francois-Xavier Coudert from comment #16) > I feel like the "array subscript has type char" error is really a red > herring in this case. I agree, especially for C programmers who are not aware that the functions from <ctype.h> are most often implemented as macros. GCC should try to bridge this gap and provide a more accurate, more helpful diagnostic in cases like these. > The four functions currently used in libgfortran are: isalnum, isdigit, > tolower, toupper. Patch incoming. I already attached a patch 18 months ago, using the standard pattern that everyone else uses to properly fix the type mismatch. I don't think much has changed in the meantime, so my patch should still apply. Here are some ideas for implementing this check in a more direct way: https://github.com/NetBSD/src/blob/trunk/usr.bin/xlint/lint1/ckctype.c https://github.com/NetBSD/src/blob/trunk/tests/usr.bin/xlint/lint1/msg_341.c https://github.com/NetBSD/src/blob/trunk/tests/usr.bin/xlint/lint1/msg_342.c
