[Bug c++/11694] New: Template member class of template class mix-up

[Bug c++/11694] New: Template member class of template class mix-up

[cholm at nbi dot dk]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11694

           Summary: Template member class of template class mix-up
           Product: gcc
           Version: 3.2.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: cholm at nbi dot dk
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu

Hi GCC developers,

I think I stumbled on a bug in G++.  It has to do with template nested classes 
in template classes.  It seems that there's something missing in the parse. 
Maybe it has something to do with the `second template pass bug'? 

Please find the file `baz.cc' below.

  prompt> g++-3.2 baz.cc -o baz
   g++-3.2 baz.cc -o baz
  baz.cc: In instantiation of `bar<double>':
  baz.cc:47:   instantiated from here
  baz.cc:20: internal error: Segmentation fault
  Please submit a full bug report,
  with preprocessed source if appropriate.
  See <URL:http://www.gnu.org/software/gcc/bugs.html> for instructions.

My machine is a dual Intel Celeron, running Linux 2.4.18 SMP, with
GLibC version 2.2.5-11.  The distribution is Debian GNU/Linux 3.0
(woody) with some extra packages from testing (sarge).

GCC is:

  prompt> gcc-3.2 -v
  Reading specs from /usr/lib/gcc-lib/i386-linux/3.2.2/specs
  Configured with: ../src/configure -v --enable-
languages=c,c++,java,f77,proto,p
ascal,objc,ada --prefix=/usr --mandir=/usr/share/man --
infodir=/usr/share/info -
-with-gxx-include-dir=/usr/include/c++/3.2 --enable-shared --with-system-zlib -
-
enable-nls --without-included-gettext --disable-__cxa_atexit --enable-java-
gc=bo
ehm --enable-objc-gc i386-linux
  Thread model: posix
  gcc version 3.2.2

Note, that the `baz.cc' file compiles fine with Intel C++ version
7.0.

If I change the source, so that the `bar' class takes two template
parameters, like:

  template <typename A, typename B=A>
  struct bar : public foo<A, B>
  {
    typedef foo<A , B> base_type;
    typedef base_type::helper<1> helper_type;
    helper_type _help;

    bar(const A& a) : base_type(a, a), _help() {}
    virtual int doit() { return _help.doit(_a,_b); }
  };

it compiles fine.

If I in the `baz' class changes the definition of `helper_type' to
directly reference the sub-class of `foo<A,B>', like:

  template <typename A>
  struct baz : public bar<A>
  {
    typedef bar<A>              base_type;
    typedef foo<A,A>::helper<1> helper_type;
    helper_type* _helper;
    baz() : base_type(42) { _helper = new helper_type(2); }
    int doit() { return _helper->doit(_a,_b); }
  };

then I get:

  > g++-3.2 baz.cc -o baz
  bar.cc: In constructor `baz<A>::baz() [with A = double]':
  bar.cc:50:   instantiated from here
  bar.cc:36: invalid use of undefined type `struct foo<double, B>::helper<1>'
  bar.cc:6: declaration of `struct foo<double, B>::helper<1>'
  bar.cc: In member function `int baz<A>::doit() [with A = double]':
  bar.cc:51:   instantiated from here
  bar.cc:37: no matching function for call to `foo<double, B>::helper<1>::doit(
     double&, double&)'

Again, Intel C++ version 7.0 compiles that just fine

Only if I instancises `foo<A,B>::helper<C>' with explicit types for
`A' and `B', like:

  template <typename A>
  struct baz : public bar<A>
  {
    typedef bar<A>              base_type;
    typedef foo<double,double>::helper<1> helper_type;
    helper_type* _helper;
    baz() : base_type(42) { _helper = new helper_type(2); }
    int doit() { return _helper->doit(_a,_b); }
  };

can I get an error free compile

The contens of `baz.cc' follows below:
//====================================================================
template <typename A, typename B>
struct foo {
  template <int C>
  struct helper
  {
    helper() {}
    int doit(const A& a, const B& b) { return C + int(a) + int(b); }
  };
  A _a;
  B _b;
  foo() : _a(0), _b(0) {}
  foo(const A& a, const B& b) : _a(a), _b(b) {}
  virtual int doit() { return 0; }
};

//====================================================================
template <typename A>
struct bar : public foo<A, A>
{
  typedef foo<A , A> base_type;
  typedef base_type::helper<1> helper_type;
  helper_type _help;

  bar(const A& a) : base_type(a, a), _help() {}
  virtual int doit() { return _help.doit(_a,_b); }
};

//====================================================================
template <typename A>
struct baz : public bar<A>
{
  typedef bar<A>                          base_type;
  typedef typename base_type::helper_type helper_type;
  helper_type* _helper;
  baz() : base_type(42) { _helper = new helper_type(); }
  int doit() { return _helper->doit(_a,_b); }
};

//====================================================================
int
main(int argc, char** argv)
{

  foo<double, double> foo(3.14, 42);

  bar<double> b1(3.14);
  int a1 = b1.doit();

  baz<double> b2;
  int a2 = b2.doit();

  return 0;
}

//
// EOF of `baz.cc'
//

Yours, 

 ___  |  Christian Holm Christensen
  |_| |  -------------------------------------------------------------
    | |  Address: Sankt Hansgade 23, 1. th.  Phone:  (+45) 35 35 96 91
     _|           DK-2200 Copenhagen N       Cell:   (+45) 24 61 85 91
    _|            Denmark                    Office: (+45) 353  25 305
 ____|   Email:   cholm@nbi.dk               Web:    www.nbi.dk/~cholm
 | |

[Bug c++/11694] Template member class of template class mix-up

[pinskia at physics dot uc dot edu]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11694



------- Additional Comments From pinskia at physics dot uc dot edu  2003-07-28 14:08 -------
icc 6.0 rejects it with strict turned on (-Xc):
tin:~/src/gnu/gcctest>/opt/intel/compiler60/ia32/bin/icc pr11694.cc -Xc
pr11694.cc
pr11694.cc(21): error: nontype "foo<A, B>::helper [with A=A, B=A]" is not a template
    typedef base_type::helper<1> helper_type;
                       ^

pr11694.cc(25): error: identifier "_a" is undefined
    virtual int doit() { return _help.doit(_a,_b); }
                                           ^

pr11694.cc(25): error: identifier "_b" is undefined
    virtual int doit() { return _help.doit(_a,_b); }
                                              ^

pr11694.cc(36): error: identifier "_a" is undefined
    int doit() { return _helper->doit(_a,_b); }
                                      ^

pr11694.cc(36): error: identifier "_b" is undefined
    int doit() { return _helper->doit(_a,_b); }
                                         ^

compilation aborted for pr11694.cc (code 2)


The mainline (20030728) of GCC rejects it also:

pr11694.cc:21: error: ISO C++ forbids declaration of `helper' with no type
pr11694.cc:21: error: cannot declare member `foo<A, A>::helper' within `bar<A>'
pr11694.cc:21: error: expected `;'
pr11694.cc:22: error: `helper_type' does not name a type
pr11694.cc: In constructor `bar<A>::bar(const A&)':
pr11694.cc:24: error: class `bar<A>' does not have any field named `_help'
pr11694.cc: In member function `virtual int bar<A>::doit()':
pr11694.cc:25: error: `_help' undeclared (first use this function)
pr11694.cc:25: error: (Each undeclared identifier is reported only once for 
   each function it appears in.)
pr11694.cc:25: error: `_a' undeclared (first use this function)
pr11694.cc:25: error: `_b' undeclared (first use this function)
pr11694.cc: In member function `int baz<A>::doit()':
pr11694.cc:36: error: `_a' undeclared (first use this function)
pr11694.cc:36: error: `_b' undeclared (first use this function)
pr11694.cc: At global scope:
pr11694.cc: In instantiation of `baz<double>':
pr11694.cc:49:   instantiated from here
pr11694.cc:33: error: no type named `helper_type' in `struct bar<double>'
pr11694.cc:34: error: no type named `helper_type' in `struct bar<double>'
pr11694.cc: In constructor `baz<A>::baz() [with A = double]':
pr11694.cc:49:   instantiated from here
pr11694.cc:35: error: no type named `helper_type' in `struct bar<double>'
pr11694.cc:35: error: `_helper' undeclared (first use this function)
pr11694.cc: In member function `int baz<A>::doit() [with A = double]':
pr11694.cc:50:   instantiated from here
pr11694.cc:36: error: `_helper' undeclared (first use this function)

GCC 2.95.3 also rejects it:

pr11694.cc: In method `bar<double>::bar(const double &)':
pr11694.cc:46:   instantiated from here
pr11694.cc:24: no matching function for call to `foo<double,B>::helper<1>::helper 
(foo<double,B>::helper<1>)'
pr11694.cc: In method `int bar<double>::doit()':
pr11694.cc:47:   instantiated from here
pr11694.cc:25: no matching function for call to `foo<double,B>::helper<1>::doit (double &, 
double &)'
pr11694.cc: In method `baz<double>::baz()':
pr11694.cc:49:   instantiated from here
pr11694.cc:35: invalid use of undefined type `struct foo<double,B>::helper<1>'
pr11694.cc:8: forward declaration of `struct foo<double,B>::helper<1>'
pr11694.cc: In method `int baz<double>::doit()':
pr11694.cc:50:   instantiated from here
pr11694.cc:36: no matching function for call to `foo<double,B>::helper<1>::doit (double &, 
double &)'

[Bug c++/11694] ICE with missing typename/template keywords

[ehrhardt at mathematik dot uni-ulm dot de]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11694


ehrhardt at mathematik dot uni-ulm dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |ice-on-invalid-code
           Priority|P2                          |P3
   Last reconfirmed|0000-00-00 00:00:00         |2003-07-29 09:57:44
               date|                            |
            Summary|Template member class of    |ICE with missing
                   |template class mix-up       |typename/template keywords
   Target Milestone|3.4                         |3.3.2
            Version|3.2.2                       |3.3.1


------- Additional Comments From ehrhardt at mathematik dot uni-ulm dot de  2003-07-29 09:57 -------
The code is invalid. This line:

	typedef foo<A, A>::helper<1> helper_type;

must be written as

	typedef typename foo<A, A>::template helper<1> helper_type;

However, gcc should not issue an Internal Compiler Error. This is
fixed in 3.4. Note that there are two different ICEs, one if both
typename and template are are missing. There's another one if
template is there but typename is missing.

Reduced example:

template <typename , typename >
struct foo {
	template <int> struct helper { };   
};
template <typename A>
struct bar : public foo<A, A>
{ 
	typedef foo<A, A>::helper<1> helper_type;
};
bar<double> b1();

   regards  Christian

[Bug c++/11694] [3.3 Regression] ICE with missing typename/template keywords

[pinskia at physics dot uc dot edu]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11694


pinskia at physics dot uc dot edu changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|ICE with missing            |[3.3 Regression] ICE with
                   |typename/template keywords  |missing typename/template
                   |                            |keywords


------- Additional Comments From pinskia at physics dot uc dot edu  2003-07-29 12:16 -------
3.3.1 (20030707) does not ICE on the reduced testcase but does on the full testcase
Also the full source does not ICE in 2.95.3 so making this a regression.

[Bug c++/11694] [3.3 Regression] ICE with missing typename/template keywords

[mmitchel at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11694


mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|3.3.2                       |3.3.3


------- Additional Comments From mmitchel at gcc dot gnu dot org  2003-10-16 09:24 -------
Postponed until GCC 3.3.3.

[Bug c++/11694] [3.3 Regression] ICE with missing typename/template keywords

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11694


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|3.3.3                       |3.4


------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-19 22:12 -------
Closing as fixed as this is an error-recovery problem and it is fixed on the mainline.