[Bug c++/66371] ICE: canonical types differ for identical types

["trippels at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66371

Markus Trippelsdorf <trippels at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-06-02
                 CC|                            |trippels at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
This is what creduce came up with:

trippels@gcc75 ~ % cat cc.ii
namespace std {
template <typename _Tp, _Tp> struct A;
template <typename, typename> struct B;
template <bool> struct enable_if;
template <typename> class allocator;
template <typename = allocator<int>> class vector {};
}
namespace meta {
template <typename T, T...> struct C;
template <bool B> using bool_ = std::A<bool, B>;
template <typename> struct D;
template <template <typename> class> struct quote;
template <bool... Bools> using and_c = std::B<C<bool, Bools...>, C<bool>>;
template <typename> using fast_and = and_c<>;
}
template <typename I, typename> using common_iterator = I;
template <typename T> struct static_const { static constexpr T value{}; };
template <typename> int _nullptr_v;
template <typename Concept>
struct F : meta::bool_<decltype(_nullptr_v<Concept>)::value> {};
template <typename...> using Constructible = struct View;
template <typename> using range_iterator_t = View;
template <typename> using range_sentinel_t = View;
template <typename Rng>
using range_common_iterator_t =
    common_iterator<range_iterator_t<Rng>, range_sentinel_t<Rng>>;
template <typename, typename I> using ReserveAndAssignable = F<I>;
template <typename Rng, typename = range_common_iterator_t<Rng>>
using ConvertibleToContainer = meta::fast_and<Constructible<>>;
template <typename> struct to_container_fn {
  template <typename C, typename R>
  using ReserveConcept = meta::fast_and<ReserveAndAssignable<C, R>>;
  template <typename Rng, typename Cont,
            typename std::enable_if<ConvertibleToContainer<Cont>() &&
                                    ReserveConcept<Cont, Rng>()>::type>
  void m_fn1();
};
auto to_vector =
static_const<to_container_fn<meta::quote<std::vector>>>::value;
template <typename Cont> to_container_fn<meta::D<Cont>> to_();
struct G {
  operator std::vector<std::allocator<int>>() { to_<std::vector<>>(); }
};

trippels@gcc75 ~ % g++ -std=c++14 -c cc.ii
cc.ii: In instantiation of ?struct
to_container_fn<meta::D<std::vector<std::allocator<int> > > >?:
cc.ii:41:68:   required from here
cc.ii:36:8: internal compiler error: canonical types differ for identical types
std::enable_if<(ConvertibleToContainer<Cont>() && to_container_fn<
<template-parameter-1-1> >::ReserveConcept<Cont, Rng>())> and
std::enable_if<(ConvertibleToContainer<Cont, range_common_iterator_t<Cont> >()
&& to_container_fn<meta::quote<std::vector> >::ReserveConcept<Cont, Rng>())>
   void m_fn1();
        ^