[Bug c++/20172] New: member function template declaration not instantiated during the instantiation of the enclosing class template

[Bug c++/20172] New: member function template declaration not instantiated during the instantiation of the enclosing class template

[SWElef at post dot sk]

gcc accepts the following ill-formed code (tested with gcc3.4.2 (mingw)
and various cygwin versions (from 3.3.1 to 3.4.3 and an experimental
snapshot 4.0.0-20050130) ):

template <typename T>
struct foo{
  template <T t>
  static void bar() { }
};

template <typename T>
foo<T> tester(T) { return foo<T>(); }

int main(){
  tester(1.2);
  return 0;
}

std:14.7.1/1 says

... The implicit instantiation of a class template specialization causes the
    implicit instantiation of the declarations, but not of the definitions or
    default arguments, of the class member functions, member classes, static
    data members and _member_templates_; ...

Thus, the implicit instantiation of struct foo<double> causes the
instantiation of declaration
    template <double t> void foo<double>::bar();
which is ill-formed and should be diagnosed.

Remark 1:
    The signature of bar is unimportant, it just has to be a function.
    If one declares a nested "template <T t> struct S;" gcc correctly
    complains when instantiating foo<double>.

Remark 2:
    Shorter testcase consists of a declaration of the template foo and an
    explicit instantiation of foo<double>, but the wording for implicit
    instantiation is much cleaner in this case so I decided to use it.

Regards,
Vladimir Marko

-- 
           Summary: member function template declaration not instantiated
                    during the instantiation of the enclosing class template
           Product: gcc
           Version: 3.4.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: SWElef at post dot sk
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20172

[Bug c++/20172] member function template declaration not instantiated during the instantiation of the enclosing class template

[SWElef at post dot sk]

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20172

[Bug c++/20172] member function template declaration not instantiated during the instantiation of the enclosing class template

[reichelt at gcc dot gnu dot org]

------- Additional Comments From reichelt at gcc dot gnu dot org  2005-02-25 09:13 -------
Confirmed. Accepted since at least gcc 2.95.3.
Reduced testcase:

================================
template<typename T> struct A
{
    template<T> void foo();
};

A<double> a;
================================

Even A<void> is accepted.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |reichelt at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |monitored
   Last reconfirmed|0000-00-00 00:00:00         |2005-02-25 09:13:12
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20172

[Bug c++/20172] Invalid non-type template parameters not diagnosed

[reichelt at gcc dot gnu dot org]

------- Additional Comments From reichelt at gcc dot gnu dot org  2005-06-10 09:58 -------
Actually gcc does instantiate the declarations.
It just doesn't check whether the non-type template arguments are
valid in this situation.

Adjusting the summary accordingly.

Patch posted.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |reichelt at gcc dot gnu dot
                   |dot org                     |org
                URL|                            |http://gcc.gnu.org/ml/gcc-
                   |                            |patches/2005-
                   |                            |06/msg00952.html
             Status|NEW                         |ASSIGNED
           Keywords|                            |patch
            Summary|member function template    |Invalid non-type template
                   |declaration not instantiated|parameters not diagnosed
                   |during the instantiation of |
                   |the enclosing class template|


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20172

[Bug c++/20172] Invalid non-type template parameters not diagnosed

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-07-12 16:08 -------
Subject: Bug 20172

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	nathan@gcc.gnu.org	2005-07-12 16:07:39

Modified files:
	gcc/cp         : ChangeLog pt.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/g++.dg/template: nontype12.C 

Log message:
	cp:
	PR c++/20172
	* pt.c (tsubst_template_parms): Check for invalid non-type
	parameters.
	testsuite:
	PR c++/20172
	* g++.dg/template/nontype12.C : New test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/ChangeLog.diff?cvsroot=gcc&r1=1.4817&r2=1.4818
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/pt.c.diff?cvsroot=gcc&r1=1.1014&r2=1.1015
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.5752&r2=1.5753
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/template/nontype12.C.diff?cvsroot=gcc&r1=NONE&r2=1.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20172

[Bug c++/20172] Invalid non-type template parameters not diagnosed

[reichelt at gcc dot gnu dot org]

------- Additional Comments From reichelt at gcc dot gnu dot org  2005-07-13 09:41 -------
Fixed on mainline.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20172