Possible template parser bug

  • Thread starter Thread starter Hendrik Schober
  • Start date Start date
H

Hendrik Schober

Hi,

this is a cut down version of some some template
meta stuff that I have:

///////////////////////////////////////////////////////
template< typename TL, typename TR >
struct Dummy1 {};

template< typename TL, typename TR
, template<typename,typename> class TDummy >
struct Operation;

template< typename TL1, typename TL2
, typename TR
, template<typename,typename> class TDummy >
struct Operation< TDummy<TL1,TL2>
, TR
, TDummy > {
typedef TDummy<TL1,TL1> Result;
};

template< typename TL1, typename TL2
, typename TR1, typename TR2
, template<typename,typename> class TDummy >
struct Operation< TDummy<TL1,TL2>
, TDummy<TR1,TR2>
, TDummy > {
typedef TDummy<TL1,TL1> Result;
};

typedef Dummy1<int ,float > T1A;
typedef Dummy1<long,double> T1B;

typedef Operation< T1A , T1B , Dummy1 >::Result T3;
///////////////////////////////////////////////////////

Comeau and CodeWarrior 9 agree with me that this code
is fine. VC7.1, however, barks at me:

test.cpp(29) : error C2752: 'Operation<TL,TR,TDummy>' :
more than one partial specialization matches the template argument list
test.cpp(24): could be 'Operation< TDummy<TL1,TL2>, TDummy<TR1,TR2>, TDummy >'
test.cpp(15): or 'Operation< TDummy<TL1,TL2>, TR, TDummy >'

I think this is a bug in VC7.1.
I cannot currently test this with VC8.

Schobi

--
(e-mail address removed) is never read
I'm Schobi at suespammers dot org

"The presence of those seeking the truth is infinitely
to be prefered to those thinking they've found it."
Terry Pratchett
 
Hendrik said:
I think this is a bug in VC7.1.
Click to expand...

I think you're right, but I haven't spent the time to really argue that
case.
I cannot currently test this with VC8.
Click to expand...

VC8 (Beta 1 Refresh) produces the same error messages as 7.1.

-cd
 
Carl Daniel said:
I think you're right, but I haven't spent the time to really argue that
case.


VC8 (Beta 1 Refresh) produces the same error messages as 7.1.
Click to expand...

Interestingly, GCC agrees with VC here. (Which
is rather rare IME. <g> )
Nevertheless, due to experience I tend to trust
Comeau and CW over VC and GCC.
-cd
Click to expand...


Schobi

--
(e-mail address removed) is never read
I'm Schobi at suespammers dot org

"The presence of those seeking the truth is infinitely
to be prefered to those thinking they've found it."
Terry Pratchett
 
Hendrik said:
Interestingly, GCC agrees with VC here. (Which
is rather rare IME. <g> )
Nevertheless, due to experience I tend to trust
Comeau and CW over VC and GCC.
Click to expand...

Yes, Comeau and CW are correct. The second partial specialization is
clearly more specialized than the first (you can synthesize types from
the first that the second can't match but not vice versa).

Tom
 
Tom Widmer said:
[...]
Yes, Comeau and CW are correct. The second partial specialization is
clearly more specialized than the first (you can synthesize types from
the first that the second can't match but not vice versa).
Click to expand...

Thanks, Tom. That's what I figured, although
I couldn't word it as good as you. :)
I should report this then.
Tom
Click to expand...


Schobi

--
(e-mail address removed) is never read
I'm Schobi at suespammers dot org

"The presence of those seeking the truth is infinitely
to be prefered to those thinking they've found it."
Terry Pratchett
 
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