[Bug c/57653] filename information discarded when using -imacros

[manu at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57653

--- Comment #16 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
(In reply to Allan McRae from comment #15)
> 
> I tried with -include foo.h and a breakpoint in push_command_line_include...
> I just stepped through from that breakpoint and saw cpp_push_default_include
> being called for both stdc-predef.h and foo.h.  That also gives the correct
> output.
> 
> # gcc-4.9 -include foo.h foo.c
> foo.c: In function ‘main’:
> foo.c:1:21: error: expected expression before ‘}’ token
>  int main() { return }

What is the trace of LC_ messages produced here? It seems the -imacros code is
missing something. Actually, if you could attach the corresponding gdb session
like you did earlier, it would be helpful to compare both.