[Bug c++/15480] New: ICE with sizeof(T().f()) as template parameter in function resolution

[Bug c++/15480] New: ICE with sizeof(T().f()) as template parameter in function resolution

[gianni at mariani dot ws]

Below is a template that is supposed to discover wether a type contains a method
 named "Function".

Comeau compiles this fine on Comeau C/C++ 4.3.3, fails on MSC++ 7.1 with what
seems to be the wrong error and ICE's on gcc 3.4.0.



typedef char MPT_False;

struct MPT_True { int m[2]; };


template <unsigned int w_siz>
struct MPT_IntToType
{
    typedef char    type[ w_siz ];
};

template <typename w_D>
struct MPT_Finder_Member
{
    template <typename w_T>
    static MPT_True finder(
        const w_T *,
        typename MPT_IntToType<
            sizeof(w_T().Function())
//          sizeof(static_cast<w_T>(0)->Function()) //fails same way
        >::type * = 0
    );
        
    static MPT_False finder( const w_D * );

};

template <typename w_D >
struct MPT_ContainsFuncMember
{
    struct DerivedClass : w_D
    {
    };

    typedef DerivedClass  * DerivedClassp;

    enum {
        value = (
            sizeof( MPT_Finder_Member<w_D>::finder( DerivedClassp() ) )
            == sizeof( MPT_True )
        )
    };
    
};


struct A
{
};

struct B
{
    int Function();
};

#include <iostream>

int main()
{
    std::cout << MPT_ContainsFuncMember<A>::value << "\n";
    std::cout << MPT_ContainsFuncMember<B>::value << "\n";
}

-- 
           Summary: ICE with sizeof(T().f()) as template parameter in
                    function resolution
           Product: gcc
           Version: 3.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: gianni at mariani dot ws
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i386-redhat-linux
  GCC host triplet: i386-redhat-linux
GCC target triplet: i386-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15480

[Bug c++/15480] ICE with sizeof(T().f()) as template parameter in function resolution

[gianni at mariani dot ws]

------- Additional Comments From gianni at mariani dot ws  2004-05-16 21:29 -------

Adding ice-on-valid-code kw.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15480

[Bug c++/15480] ICE with sizeof(T().f()) as template parameter in function resolution

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-05-16 21:39 -------
Confirmed.
Here is a simplied example (it might be turned into invalid though):
template <unsigned int w_siz>
struct MPT_IntToType
{
    typedef char    type;
};
template <typename w_D>
struct MPT_Finder_Member
{
    template <typename w_T>
    static int finder(
        const w_T *,
        typename MPT_IntToType<
            sizeof(w_T().Function())
        >::type * = 0
    );
    static int finder( const w_D * );
};
template <typename w_D >
struct MPT_ContainsFuncMember
{
    struct DerivedClass : w_D{};
    typedef DerivedClass  * DerivedClassp;
    enum {
        value = (
            sizeof( MPT_Finder_Member<w_D>::finder( DerivedClassp() ) )
            == sizeof( int)
        )
    };
};
struct A{};
int t = MPT_ContainsFuncMember<A>::value;

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2004-05-16 21:39:06
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15480

[Bug c++/15480] ICE with sizeof(T().f()) as template parameter in function resolution

[giovannibajo at libero dot it]

------- Additional Comments From giovannibajo at libero dot it  2004-05-17 00:47 -------
Fails with 3.2.3, 3.3.3, 3.4.0 and current mainline. Interestingly enough, it 
used to work with 3.4.0 20040216.

What does it happen with 2.95?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |3.2.3 3.3.3 3.4.0 3.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15480

[Bug c++/15480] ICE with sizeof(T().f()) as template parameter in function resolution

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-05-17 00:57 -------
2.95.3 and 3.0.4 fails (I had forgot to fill in known to fail, woops).

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|3.2.3 3.3.3 3.4.0 3.5.0     |3.2.3 3.3.3 3.4.0 3.5.0
                   |                            |2.95.3 3.0.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15480

[Bug c++/15480] ICE with sizeof(T().f()) as template parameter in function resolution

[gianni at mariani dot ws]

------- Additional Comments From gianni at mariani dot ws  2004-05-17 03:48 -------

I get this error when removing the templates:

xx6.cpp:43: sorry, unimplemented: call_expr cannot be mangled due to a defect in
the C++ ABI


------------------------------
typedef char MPT_False;
typedef int MPT_True;

template <unsigned w_siz>
struct MPT_IntToType
{
    typedef char    type[ 1 ];
};

struct B
{
    int Function();
};

struct DerivedClass_B : B
{
};

struct FinderM
{

    template <typename w_T>
    static MPT_True finder(
        const w_T *,
        typename MPT_IntToType<
            sizeof(static_cast<w_T *>(0)->Function())
        >::type * = 0
    );

    static MPT_False finder( const B * );

};

bool  value = 
    sizeof( FinderM::finder( static_cast<DerivedClass_B *>(0) ) ) == sizeof(
MPT_True );


------------------------------


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15480

[Bug c++/15480] ICE with sizeof(T().f()) as template parameter in function resolution

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-05-17 02:56 -------
Here is a yet simpler example: 
------------------- 
template <int> struct S {}; 
 
template <int> struct G { 
    template <typename U> 
    static int finder(U *, S< sizeof(U().foo()) > * = 0); 
 
    static int finder (int *); 
}; 
 
int t = sizeof( G<1>::finder( (int*)0 ) ); 
--------------------- 
We ICE on this: 
g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -c x.cc 
x.cc: In instantiation of `G<1>': 
x.cc:10:   instantiated from here 
x.cc:5: internal compiler error: Segmentation fault 
Please submit a full bug report, 
with preprocessed source if appropriate. 
See <URL:http://gcc.gnu.org/bugs.html> for instructions. 
 
 
I wonder if this is somehow related to the fact that we 
(spuriously) don't accept this code (the same as above, 
just that G isn't a template: 
------------------- 
template <int> struct S {}; 
 
struct G { 
    template <typename U> 
    static int finder(U *, S< sizeof(U().foo()) > * = 0); 
 
    static int finder (int *); 
}; 
 
int t = sizeof( G::finder( (int*)0 ) ); 
-------------------- 
 
g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -c x.cc 
x.cc:10: error: request for member `foo' in `0', which is of non-class type 
`int' 
 
This should be just a SFINAE. 
 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15480

[Bug c++/15480] ICE with sizeof(T().f()) as template parameter in function resolution

[gianni at mariani dot ws]

------- Additional Comments From gianni at mariani dot ws  2004-05-17 06:26 -------

I don't know if this is related to this bug but I think this code is also not
correctly parsed by gcc.  Again comeau compiles this fine and MSVC ++ gets all
confused about not being able to deduce func in a similar way to gcc.


typedef char MPT_False;
typedef int MPT_True;


template <unsigned int w_siz>
struct MPT_IntToType
{
    typedef char    type;
};

template <typename T1, typename T2>
int func( T2 ( T1::* )() );

template <typename w_D>
struct MPT_Finder_Member
{

    template <typename w_T>
    static MPT_True finder(
        const w_T *,
        typename MPT_IntToType<
            sizeof( func( & w_T::Function ) )
        >::type * = 0
    );
        
    static MPT_False finder( const w_D * );

};

template <typename w_D >
struct MPT_ContainsFuncMember
{
    struct DerivedClass : w_D
    {
    };

    typedef DerivedClass  * DerivedClassp;

    enum {
        value = (
            sizeof( MPT_Finder_Member<w_D>::finder( DerivedClassp() ) )
            == sizeof( MPT_True )
        )
    };
    
};


struct A
{
};

struct B
{
    int Function();
};

// this works find so func<T1,T2> can be deduced
int x = sizeof( func( &B::Function ) );
int y = MPT_ContainsFuncMember<A>::value;
int z = MPT_ContainsFuncMember<B>::value;



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15480

[Bug c++/15480] ICE with sizeof(T().f()) as template parameter in function resolution

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-06 02:01 -------
(In reply to comment #5)
> Here is a yet simpler example: 
We reject this now (and not ICE).

>  I wonder if this is somehow related to the fact that we 
> (spuriously) don't accept this code (the same as above, 
And we reject this still.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
   Last reconfirmed|2004-05-16 21:39:06         |2005-01-06 02:01:09
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15480

[Bug c++/15480] ICE with sizeof(T().f()) as template parameter in function resolution

[pinskia at gcc dot gnu dot org]

------- Comment #10 from pinskia at gcc dot gnu dot org  2009-04-16 16:35 -------
Fixed at least on the trunk.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15480