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Bug#431045: marked as done (g++-4.2: Template arguments to template functions not working)

Your message dated Mon, 23 Jul 2007 11:20:43 +0200
with message-id <18084.29419.995167.292892@gargle.gargle.HOWL>
and subject line Bug#431045: Question about validity of wfmath template code
has caused the attached Bug report to be marked as done.

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If this is not the case it is now your responsibility to reopen the
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--- Begin Message --- 
Package: g++-4.2
Version: 4.2-20070627-1
Severity: normal

I condensed the wfmath build failure with gcc-4.2 (#361815) into a small test
case:

frobnitz:/tmp# cat test.cc
#include <vector>

template <template<class> class container>
int sum(const container<int>& x) {
  int result = 0;
  for (typename container<int>::const_iterator i = x.begin(); i != x.end(); i++) result += *i;
  return result;
}

int test() {
  std::vector<int> x;
  return sum(x);
}
frobnitz:/tmp# g++-4.1 -c test.cc
frobnitz:/tmp# g++-4.2 -c test.cc
test.cc: In function 'int test()':
test.cc:12: error: no matching function for call to 'sum(std::vector<int, std::allocator<int> >&)'
frobnitz:/tmp# /usr/lib/gcc-snapshot/bin/g++ -c test.cc
test.cc: In function 'int test()':
test.cc:12: error: no matching function for call to 'sum(std::vector<int, std::allocator<int> >&)'
-- 
Daniel Schepler

--- End Message ---
--- Begin Message --- 
Daniel Schepler writes:
> After analyzing a build failure of wfmath with gcc-4.2, I condensed the issue 
> it was having to the following test case:
> 
> template <class T, class U = int> class A { public: T x1; U x2; };
> template <template<class> class container_with_x1>
> int f(const container_with_x1<int>& y) {
>   return y.x1;
> }
> int g() {
>   A<int> y;
>   return f(y);
> }
> 
> This code compiles with g++-4.1, but fails with g++-4.2 and the snapshot of 
> g++-4.3 currently in Debian's gcc-snapshot package.  My question is: is this 
> valid code or not?

Brian M. Carlson writes:
> According to http://gcc.gnu.org/gcc-4.2/changes.html (second bullet
> point under C++), I don't believe this is valid.  The example you gave
> and the example on the changes page look very, very similar, and are
> probably isomorphic, which does not bode well for wfmath.

--- End Message ---
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