[Bug c++/32029] New: Internal Compiler Error on instantiation of template parameter

[Bug c++/32029] New: Internal Compiler Error on instantiation of template parameter

[ejt at andrew dot cmu dot edu]

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When there is a default template parameter based on a templated class member
type, the compiler dies a nasty death.  As far as I can tell, gcc prior to 4.1
branch works fine, but all of the 4.1 branch seems to have this problem.

Quick summary... This works:
  template<class T, Al=typename Factory0Arg<T>::template Factory<T> > class
thing {/*...*/};

This ICEs:
  template<class T, Al=class Factory0Arg<T>::Factory<T> > class thing
{/*...*/};
whenever you try to instantiate 'thing', as seen below:
$ g++ -Wall bug.cc -o bug
bug.cc: In instantiation of ‘Factory0Arg<foo>::Factory<foo>’:
bug.cc:41:   instantiated from ‘void thing<T, Al>::makeIt() [with T = foo, Al =
Factory0Arg<foo>::Factory<foo>]’
bug.cc:53:   instantiated from here
bug.cc:19: internal compiler error: in instantiate_class_template, at
cp/pt.c:5666

I would at least hope for a better error message assuming that's not valid
syntax ;)

I'll attach original and preprocessed source.


-- 
           Summary: Internal Compiler Error on instantiation of template
                    parameter
           Product: gcc
           Version: 4.1.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ejt at andrew dot cmu dot edu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32029

[Bug c++/32029] Internal Compiler Error on instantiation of template parameter

[ejt at andrew dot cmu dot edu]

------- Comment #1 from ejt at andrew dot cmu dot edu  2007-05-22 05:00 -------
Created an attachment (id=13599)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13599&action=view)
Original source


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32029

[Bug c++/32029] Internal Compiler Error on instantiation of template parameter

[ejt at andrew dot cmu dot edu]

------- Comment #2 from ejt at andrew dot cmu dot edu  2007-05-22 05:01 -------
Created an attachment (id=13600)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13600&action=view)
Preprocessed source


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32029

[Bug c++/32029] Internal Compiler Error on instantiation of template parameter

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2007-05-24 03:18 -------
Here is a reduced testcase:
template<class Base>
struct Factory0Arg
{
        template<class T> struct Factory { };
};
template<class T, class Al=class Factory0Arg<T>::Factory<T> >
struct thing {
                Al allocator;
};
thing<int> t;


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32029

[Bug c++/32029] [4.1/4.2/4.3 regression] ICE on instantiation of template parameter

[reichelt at gcc dot gnu dot org]

------- Comment #4 from reichelt at gcc dot gnu dot org  2007-12-26 20:58 -------
Confirmed.

The correct syntax for the default parameter is the one that works:
typename Factory0Arg<T>::template Factory<T>

I get an ICE since GCC 3.4.0.
Before, the code was wrongly accepted.


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reichelt at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |reichelt at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |ice-on-invalid-code,
                   |                            |monitored
   Last reconfirmed|0000-00-00 00:00:00         |2007-12-26 20:58:09
               date|                            |
            Summary|Internal Compiler Error on  |[4.1/4.2/4.3 regression] ICE
                   |instantiation of template   |on instantiation of template
                   |parameter                   |parameter
   Target Milestone|---                         |4.1.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32029

[Bug c++/32029] [4.1/4.2/4.3 regression] ICE on instantiation of template parameter

[pcarlini at suse dot de]

------- Comment #5 from pcarlini at suse dot de  2008-01-24 12:02 -------
In mainline is now back to accepts-invalid.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32029

[Bug c++/32029] [4.1/4.2/4.3 regression] ICE on instantiation of template parameter

[reichelt at gcc dot gnu dot org]

------- Comment #6 from reichelt at gcc dot gnu dot org  2008-01-26 14:07 -------
The 4.2 branch is now also back to accepts-invalid.
This is due to the fix for PR 33959.


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reichelt at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |33959


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32029

[Bug c++/32029] [4.1/4.2/4.3 regression] ICE on instantiation of template parameter

[jason at gcc dot gnu dot org]

------- Comment #7 from jason at gcc dot gnu dot org  2008-01-28 16:33 -------
The version with "class" is also valid.

14.6p5: A qualified name used as the name in a mem-initializer-id, a
base-specifier, or an elaborated-type-specifier is implicitly assumed to name a
type, without the use of the typename keyword.

Fixed by the patch for 33959.


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jason at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32029