[Bug c++/30281] New: [reject valid?] mismatch type of virtual method.

[Bug c++/30281] New: [reject valid?] mismatch type of virtual method.

[pluto at agmk dot net]

#include <stdexcept>
struct my_error : public std::runtime_error
{
        my_error( std::string const& );
};
template < typename T >
struct wrapper
{
        template < typename R >
        void add_method( R ( T::* )() const );
};
void test()
{
        wrapper< my_error >().add_method( &my_error::what );
}

g++ rejects this code:

error: no matching function for call to &#8216;wrapper<my_error>::add_method(
       const char* (std::runtime_error::*)()const)&#8217;
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
         &my_error::what has &std::runtime_error::what type? weird.

btw.
non-templated add_method( char const* ( my_error::* )() const )
works fine, so i suppose it's a bug in c++ frontend.


-- 
           Summary: [reject valid?] mismatch type of virtual method.
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pluto at agmk dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30281

[Bug c++/30281] [reject valid?] type deduction fails.

[pluto at agmk dot net]

------- Comment #1 from pluto at agmk dot net  2006-12-23 11:21 -------
wrapper< my_error >().add_method< char const* >( &my_error::what );

such call compiles, so it looks like type deduction failure.


-- 

pluto at agmk dot net changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[reject valid?] mismatch    |[reject valid?] type
                   |type of virtual method.     |deduction fails.


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30281

[Bug c++/30281] [reject valid?] type deduction fails.

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2007-01-07 00:54 -------
Reduced testcase:

struct a
{
  int g(void);
};

struct b : a { };

template < typename T >
struct wrapper
{
        template < typename R >
        void add_method( R ( T::* )() const );
};
void test()
{
        wrapper< b >().add_method( &b::g );
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30281

[Bug c++/30281] [reject valid?] type deduction fails.

[bangerth at dealii dot org]

------- Comment #3 from bangerth at dealii dot org  2007-01-21 05:23 -------
Here's an even simpler testcase that shows the same problem (even if the
error message is different):
-------------
struct a
{
  int g(void);
};

struct b : a { };

void test()
{
  static_cast<int (b::*)() const> (&b::g);
}
------------------

g/x> c++ -c x.cc
x.cc: In function 'void test()':
x.cc:10: error: invalid static_cast from type 'int (a::*)()' to type 'int
(b::*)()const'

In any case, this is a duplicate of PR 17359.

W.

*** This bug has been marked as a duplicate of 17359 ***


-- 

bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bangerth at dealii dot org
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30281