[Bug c++/86329] Bogus fix-it hint: note: suggested alternative: '._72'

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86329

--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Author: dmalcolm
Date: Wed Jun 27 23:21:46 2018
New Revision: 262199

URL: https://gcc.gnu.org/viewcvs?rev=262199&root=gcc&view=rev
Log:
C++: don't offer bogus "._0" suggestions (PR c++/86329)

PR c++/86329 reports that the C++ frontend can offer bogus suggestions like:

#include <string>

int compare()
{
  return __n1 - __n2;
}

suggested.cc: In function 'int compare()':
suggested.cc:5:10: error: '__n1' was not declared in this scope
   return __n1 - __n2;
          ^~~~
suggested.cc:5:10: note: suggested alternative: '._61'
   return __n1 - __n2;
          ^~~~
          ._61
suggested.cc:5:17: error: '__n2' was not declared in this scope
   return __n1 - __n2;
                 ^~~~
suggested.cc:5:17: note: suggested alternative: '._72'
   return __n1 - __n2;
                 ^~~~
                 ._72

The dot-prefixed names are an implementation detail of how we implement
anonymous enums found in the header files, generated via
anon_aggrname_format in make_anon_name.

This patch uses anon_aggrname_p to filter them out when considering
which names to suggest.

gcc/cp/ChangeLog:
        PR c++/86329
        * name-lookup.c (consider_binding_level): Filter out names that
        match anon_aggrname_p.

gcc/testsuite/ChangeLog:
        PR c++/86329
        * g++.dg/lookup/pr86329.C: New test.


Added:
    trunk/gcc/testsuite/g++.dg/lookup/pr86329.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/name-lookup.c
    trunk/gcc/testsuite/ChangeLog