https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91519
--- Comment #9 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
(In reply to kargl from comment #7)
> The function check_externals_expr
> is somewhat odd. It is declared to return int, but all return
> statements are 'return 0'. This suggests to me that proper
> declaration for this function is void.
It's a callback function for the expression walker. A non-zero
return value would mean an immediate return. From frontend-passes.c:
#define WALK_SUBEXPR(NODE) \
do \
{ \
result = gfc_expr_walker (&(NODE), exprfn, data); \
if (result) \
return result; \
} \
while (0)
