[patch, fortran, RFC] warn about out-of-bounds errors in DO loops

[Richard Sandiford]

Thanks for doing this, looks really useful.

Thomas Koenig <tkoenig@netcologne.de> writes:
> Well, here's a version which actually throws a hard error in
> obvious cases; the other cases are reserved for -Wextra.

Is it OK to throw a hard error for this?  Maybe the rules are different
from C and C++, but normally we can't do that for code that's only
invalid if executed.  An unconditional warning would be good though.

Thanks,
Richard