public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug c++/95074] New: Function found via ADL when it should not
@ 2020-05-12  5:17 mpolacek at gcc dot gnu.org
  2020-05-12  5:18 ` [Bug c++/95074] " mpolacek at gcc dot gnu.org
                   ` (6 more replies)
  0 siblings, 7 replies; 8+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2020-05-12  5:17 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95074

            Bug ID: 95074
           Summary: Function found via ADL when it should not
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mpolacek at gcc dot gnu.org
  Target Milestone: ---

namespace N {
  struct S { };
  void f(S);
}

namespace M {
  void f(int);
}

int
main ()
{
  N::S s;
  extern void f(char); // #1
  using M::f; // #2
  f(s);
}

compiles fine, but shouldn't: [basic.lookup.argdep]/3: If X (the lookup set
produced by unqualified lookup) contains 
-- a block-scope function declaration that is not a using-declaration
[...]
then Y (the lookup set produced by ADL) is empty.

So the M::f here is fine but #1 should prevent ADL.  But we still find N::f.

If lines #1 and #2 are switched, this test rejected.

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug c++/95074] Function found via ADL when it should not
  2020-05-12  5:17 [Bug c++/95074] New: Function found via ADL when it should not mpolacek at gcc dot gnu.org
@ 2020-05-12  5:18 ` mpolacek at gcc dot gnu.org
  2020-05-12  5:31 ` mpolacek at gcc dot gnu.org
                   ` (5 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2020-05-12  5:18 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95074

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |accepts-invalid

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Not a regression.

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug c++/95074] Function found via ADL when it should not
  2020-05-12  5:17 [Bug c++/95074] New: Function found via ADL when it should not mpolacek at gcc dot gnu.org
  2020-05-12  5:18 ` [Bug c++/95074] " mpolacek at gcc dot gnu.org
@ 2020-05-12  5:31 ` mpolacek at gcc dot gnu.org
  2020-05-12  8:50 ` redi at gcc dot gnu.org
                   ` (4 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2020-05-12  5:31 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95074

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
This is where we're confused by the function introduced by M::f:
                /* We do not perform argument-dependent lookup if
                   normal lookup finds a non-function, in accordance
                   with the expected resolution of DR 218.  */
                else if (!args->is_empty ()
                         && is_overloaded_fn (postfix_expression))
                  {
                    /* We only need to look at the first function,
                       because all the fns share the attribute we're
                       concerned with (all member fns or all local
                       fns).  */
                    tree fn = get_first_fn (postfix_expression);
                    fn = STRIP_TEMPLATE (fn); 

                    /* Do not do argument dependent lookup if regular
                       lookup finds a member function or a block-scope
                       function declaration.  [basic.lookup.argdep]/3  */
                    if (!((TREE_CODE (fn) == USING_DECL && DECL_DEPENDENT_P
(fn)) 
                          || DECL_FUNCTION_MEMBER_P (fn)
                          || DECL_LOCAL_FUNCTION_P (fn)))
                      {
                        koenig_p = true; 
                        if (!any_type_dependent_arguments_p (args))
                          postfix_expression
                            = perform_koenig_lookup (postfix_expression, args, 
                                                     complain);
                      }
                  }

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug c++/95074] Function found via ADL when it should not
  2020-05-12  5:17 [Bug c++/95074] New: Function found via ADL when it should not mpolacek at gcc dot gnu.org
  2020-05-12  5:18 ` [Bug c++/95074] " mpolacek at gcc dot gnu.org
  2020-05-12  5:31 ` mpolacek at gcc dot gnu.org
@ 2020-05-12  8:50 ` redi at gcc dot gnu.org
  2020-05-12 15:00 ` mpolacek at gcc dot gnu.org
                   ` (3 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: redi at gcc dot gnu.org @ 2020-05-12  8:50 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95074

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-05-12
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug c++/95074] Function found via ADL when it should not
  2020-05-12  5:17 [Bug c++/95074] New: Function found via ADL when it should not mpolacek at gcc dot gnu.org
                   ` (2 preceding siblings ...)
  2020-05-12  8:50 ` redi at gcc dot gnu.org
@ 2020-05-12 15:00 ` mpolacek at gcc dot gnu.org
  2020-05-12 20:26 ` cvs-commit at gcc dot gnu.org
                   ` (2 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2020-05-12 15:00 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95074

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |mpolacek at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug c++/95074] Function found via ADL when it should not
  2020-05-12  5:17 [Bug c++/95074] New: Function found via ADL when it should not mpolacek at gcc dot gnu.org
                   ` (3 preceding siblings ...)
  2020-05-12 15:00 ` mpolacek at gcc dot gnu.org
@ 2020-05-12 20:26 ` cvs-commit at gcc dot gnu.org
  2020-05-12 20:27 ` mpolacek at gcc dot gnu.org
  2021-12-03  0:54 ` pinskia at gcc dot gnu.org
  6 siblings, 0 replies; 8+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2020-05-12 20:26 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95074

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:

https://gcc.gnu.org/g:90b160f8ec515f54ddc36519a6aaa60abdabdec1

commit r11-336-g90b160f8ec515f54ddc36519a6aaa60abdabdec1
Author: Marek Polacek <polacek@redhat.com>
Date:   Tue May 12 14:56:13 2020 -0400

    c++: Function found via ADL when it should not [PR95074]

    I noticed that we don't implement [basic.lookup.argdep]/3: quite correctly;
    it says "If X (the lookup set produced by unqualified lookup) contains
    -- a block-scope function declaration that is not a using-declaration
    [...]
    then Y (the lookup set produced by ADL) is empty."
    but we were still performing ADL in fn1 in the attached test.  The
    problem was that we were only looking at the first function in the
    overload set which in this case happened to be a using-declaration, and
    those don't suppress ADL.  We have to look through the whole set to find
    out if unqualified lookup found a block-scope function declaration, or
    a member function declaration.

            PR c++/95074
            * parser.c (cp_parser_postfix_expression) <case CPP_OPEN_PAREN>:
When
            looking for a block-scope function declaration, look through the
whole
            set, not just the first function in the overload set.

            * g++.dg/lookup/koenig15.C: New test.

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug c++/95074] Function found via ADL when it should not
  2020-05-12  5:17 [Bug c++/95074] New: Function found via ADL when it should not mpolacek at gcc dot gnu.org
                   ` (4 preceding siblings ...)
  2020-05-12 20:26 ` cvs-commit at gcc dot gnu.org
@ 2020-05-12 20:27 ` mpolacek at gcc dot gnu.org
  2021-12-03  0:54 ` pinskia at gcc dot gnu.org
  6 siblings, 0 replies; 8+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2020-05-12 20:27 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95074

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed in GCC 11.

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug c++/95074] Function found via ADL when it should not
  2020-05-12  5:17 [Bug c++/95074] New: Function found via ADL when it should not mpolacek at gcc dot gnu.org
                   ` (5 preceding siblings ...)
  2020-05-12 20:27 ` mpolacek at gcc dot gnu.org
@ 2021-12-03  0:54 ` pinskia at gcc dot gnu.org
  6 siblings, 0 replies; 8+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-03  0:54 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95074

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.0

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2021-12-03  0:54 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-12  5:17 [Bug c++/95074] New: Function found via ADL when it should not mpolacek at gcc dot gnu.org
2020-05-12  5:18 ` [Bug c++/95074] " mpolacek at gcc dot gnu.org
2020-05-12  5:31 ` mpolacek at gcc dot gnu.org
2020-05-12  8:50 ` redi at gcc dot gnu.org
2020-05-12 15:00 ` mpolacek at gcc dot gnu.org
2020-05-12 20:26 ` cvs-commit at gcc dot gnu.org
2020-05-12 20:27 ` mpolacek at gcc dot gnu.org
2021-12-03  0:54 ` pinskia at gcc dot gnu.org

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).