[Bug c++/33129] C++ frontend finds static function in argument dependent lookup based on template parameter

["gdr at cs dot tamu dot edu" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #1 from gdr at cs dot tamu dot edu  2007-08-21 00:23 -------
Subject: Re:   New: C++ frontend finds static function in argument dependent
lookup based on template parameter

"ian at airs dot com" <gcc-bugzilla@gcc.gnu.org> writes:

| In the C++ standard section 14.6.4.2 [temp.dep.candidate] says this:
| 
| "
| For a function call that depends on a template parameter, if the function
name
| is an unqualified-id but not a template-id, the candidate functions are found
| using the usual lookup rules (3.4.1, 3.4.2) except that:
| 
| -- For the part of the lookup using unqualified name lookup (3.4.1), only
| function declarations with external linkage from the template definition
| context are found.
| "
| 
| If I understand this correctly, it seems to me that this code should fail to
| compile:
| 
| template<typename t>
| static void f(t v) { }
| 
| template<typename t>
| void bar(t v) { f(v); }
| 
| void quux(int i) { bar(i); }

Yes, you are correct.  I'm pretty sure I already opened a PR for this,
but my memory is failing me.  I'm pretty sure I came with an example
whose meaning was changed -- in the presence of export, bug GCC does
not implement export so that aspect may be a moot point.
just while discussing

[...]

| If I'm reading the standard correctly, then this is a minor case of the C++
| frontend failing to properly diagnose an invalid C++ program.

I may also silently change the semantics of a well-formed function --
imagine a case where the static function should not be part of the
overload set.

| I noticed this because of the Sun Studio's -features=templrefstatic option. 
| The existence of this option means that if we do change the compiler, we need
| to provide an option to implement the existing behaviour.  Perhaps we should
| simply change the behaviour for -pedantic.

I believe we should warn by default and have -pedantic reject the code
in case the only candidate is a static function.

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33129