[Bug c++/91431] Using class template for containers and iterators rather than defining template only for iterators caused a trouble

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91431

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|needs-reduction             |ice-on-invalid-code

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Reduced:

template<typename T> class Blob {
public:
 template<
  template<typename> class Alloc,
  template<typename, typename = Alloc<T>> class Container,
  class Iter = typename Container<T>::iterator
 > Blob(Iter b, Iter e) {
 }
private:
};

int main()
{
 int i = 0;
 Blob<int> i_blob(&i, &i);
}

The code is invalid, you can't deduce the container and allocator from the
iterator type like that.