[Bug fortran/59016] f951: internal compiler error: Segmentation fault

["drikosev at otenet dot gr" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59016

--- Comment #7 from drikosev at otenet dot gr ---
Hi,

The reduced test case which has been posted by janus (comment 1) crashes also
4.8.4 and gcc 5.0 (the latter was copied from trunc a few days ago).

The backtrace I get agrees with that of Dominique's (comment 4). The problem is
likely in function "check_interface0"; the locus of "p->sym" is invalid when
gfc_error is called:

   gfc_error ("Procedure '%s' in %s at %L is neither function nor "
              "subroutine", p->sym->name, interface_name,
          &p->sym->declared_at);

Likely, the reason is that there is a symbol only in the access statement but
the expected function/subroutine hasn't been defined. 

Perhaps, one can avoid the segmentation fault with an addition argument in
function "check_interface0".  The argument will be not null only if called by
function "check_sym_interfaces"; in which case it will be the symbol that
appears in the access-stmt.

I'm not really if we can reproduce the error for intrinsic assignment operators
but the solution could be similar.

Provided that such a patch will be implemented, the second error message for
the example at comment 1 would look like:

pr59016.f90:2.30:

    PUBLIC :: atomic_kind_type
                              1
Error: undefined function/subroutine for generic interface 'atomic_kind_type'
at (1) 

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PS: please also note that I've not run the regression tests!