https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111218
--- Comment #5 from kargl at gcc dot gnu.org ---
Interesting bug. If one puts a break point ...
0x75917d gfc_format_decoder
/home/toon/compilers/gcc/gcc/fortran/error.cc:1078
0x2153e1f pp_format(pretty_printer*, text_info*)
/home/toon/compilers/gcc/gcc/pretty-print.cc:1475
0x21315be diagnostic_report_diagnostic(diagnostic_context*, diagnostic_info*)
/home/toon/compilers/gcc/gcc/diagnostic.cc:1606
0x9b628e gfc_report_diagnostic
/home/toon/compilers/gcc/gcc/fortran/error.cc:890
0x9b628e gfc_error_opt
/home/toon/compilers/gcc/gcc/fortran/error.cc:1460
0x9b7470 gfc_error(char const*, ...)
/home/toon/compilers/gcc/gcc/fortran/error.cc:1489
0xa6205b ambiguous_symbol
/home/toon/compilers/gcc/gcc/fortran/symbol.cc:3167
here, one ends up at
gfc_error ("Name %qs at %C is an ambiguous reference to %qs from"
"module %qs", name, st->n.sym->name, st->n.sym->module);
%C means one should use gfc_current_locus to print the offending line.
If one looks are gfc_current_locus, one sees gfc_current_locus.lb = 0x0,
an infamous NULL pointer dereference then occurs. Ouch. This patch
fixes the issue:
diff --git a/gcc/fortran/symbol.cc b/gcc/fortran/symbol.cc
index a6078bc608a..5b726f8b715 100644
--- a/gcc/fortran/symbol.cc
+++ b/gcc/fortran/symbol.cc
@@ -3164,8 +3164,16 @@ ambiguous_symbol (const char *name, gfc_symtree *st)
return;
if (st->n.sym->module)
- gfc_error ("Name %qs at %C is an ambiguous reference to %qs "
- "from module %qs", name, st->n.sym->name, st->n.sym->module);
+ {
+ if (gfc_current_locus.lb)
+ gfc_error ("Name %qs at %C is an ambiguous reference to %qs from"
+ "module %qs", name, st->n.sym->name, st->n.sym->module);
+ else
+ gfc_error ("Name %qs is an ambiguous reference to %qs, which is "
+ "available through USE association from module %qs at %L",
+ name, st->n.sym->name, st->n.sym->module,
+ &st->n.sym->declared_at);
+ }
else
gfc_error ("Name %qs at %C is an ambiguous reference to %qs "
"from current program unit", name, st->n.sym->name);
