[Bug c++/14032] New: non type boolean template argument partial specialization to argument in parent never matches

[Bug c++/14032] New: non type boolean template argument partial specialization to argument in parent never matches

[tschwinger at neoscientists dot org]

Compiled with gcc 3.3.1 (cygwin), 3.2.3 (gentoo-linux), mingw32 3.2 the test 
code included in this report generates an endless recursion.
It compiles without errors or warnings so the underlying problem can be quite 
hard to track for the user.

$ cat <<EOF >test.cpp
#include <iostream>

template <bool compare>
struct outer
{
  template <bool compare_with,bool second>
  struct inner           // unspecialized compare != compare_with
  {
    static inline void test()
    {
      std::cout << "invert" << std::endl;
      // call version with inverted template value
      inner<! compare_with, ! second>::test();
    }
  };
  template <bool second> // specialization compare == compare_with
  struct inner<compare,second>
  {
    static inline void test()
    {
      std::cout << "second: " << second << std::endl;
    }
  };
};
int main(int argc,char* argv[],char** envp)
{
  // expected output:
  //  invert
  //  second: true
  outer<false>::inner<true,false>::test();

  // expected output:
  //  second: false
  outer<true>::inner<true,false>::test();

  return 0;
}

EOF
$ make test && ./test

-- 
           Summary: non type boolean template argument partial
                    specialization to argument in parent never matches
           Product: gcc
           Version: 3.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: tschwinger at neoscientists dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[tschwinger at neoscientists dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
      Known to fail|                            |3.3.1 3.2.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-02-05 21:51 -------
Confirmed. Reduced, this looks so: 
--------------------------- 
template <bool B1> struct outer { 
    template <bool B2, bool B3> 
    struct inner { 
        static int f() { return inner<!B2,!B3>::N; }; 
    }; 
 
    template <bool B3> 
    struct inner<B1,B3> { 
        static const int N = 1; 
    }; 
}; 
 
int i = outer<false>::inner<true,false>::f(); 
--------------------------- 
This should compile, since in f() we should look into the specialization, 
but we don't. And never did. 
 
W. 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
      Known to fail|3.3.1 3.2.3                 |3.3.1 3.2.3 2.95.3 3.4.0
                   |                            |3.5.0
   Last reconfirmed|0000-00-00 00:00:00         |2004-02-05 21:51:20
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-02-05 21:54 -------
And just as a sidenote: this bug may be related to the fact 
that we reject this explicit (full) specialization in this code: 
------------------------- 
template <bool B1> struct outer { 
    template <bool B2> 
    struct inner { 
        static int f() { return inner<!B2>::N; }; 
    }; 
 
    template <> 
    struct inner<B1> { 
        static const int N = 1; 
    }; 
}; 
 
int i = outer<false>::inner<true>::f(); 
---------------------------- 
 
g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ x.cc -c 
x.cc:7: error: invalid explicit specialization before '>' token 
x.cc:7: error: explicit specialization in non-namespace scope `struct 
outer<B1>' 
x.cc:7: error: enclosing class templates are not explicitly specialized 
g/x>  
g/x> icc -c x.cc 
g/x>  

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2004-02-06 18:47 -------
Testcase in comment #2 by Wolfgang is ill-formed because of [temp.expl.spec]/2: 
explicit specializations must always be defined at namespace scope. Instead, 
partial specialization can be defined at class scope.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-02-06 19:05 -------
I was basically looking at the first line of errors only, so 
totally missed the rest. Sorry. The example in #1 should be 
valid, though. 
 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[lerdsuwa at gcc dot gnu dot org]

------- Additional Comments From lerdsuwa at gcc dot gnu dot org  2004-07-30 17:30 -------
Related to PR4882, PR13088.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[lerdsuwa at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2004-04-27 01:21:19         |2004-08-14 14:20:42
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[lerdsuwa at gcc dot gnu dot org]

------- Additional Comments From lerdsuwa at gcc dot gnu dot org  2004-11-28 10:47 -------
Work postponed to GCC 4.1.  This bug is tricky to fix.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
   Last reconfirmed|2005-05-27 01:00:14         |2005-09-23 22:49:50
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[bangerth at dealii dot org]

------- Comment #8 from bangerth at dealii dot org  2006-11-09 05:25 -------
*** Bug 29767 has been marked as a duplicate of this bug. ***


-- 

bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pluto at agmk dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032

[Bug c++/14032] non type boolean template argument partial specialization to argument in parent never matches

[lerdsuwa at gcc dot gnu dot org]

------- Comment #7 from lerdsuwa at gcc dot gnu dot org  2005-10-22 13:57 -------
Won't work on it for a long while.


-- 

lerdsuwa at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|lerdsuwa at gcc dot gnu dot |unassigned at gcc dot gnu
                   |org                         |dot org
             Status|ASSIGNED                    |NEW


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14032