[Bug c++/95986] New: Partial specialization of class template is not found when class template has NTTP of class type

["bence.kodaj at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95986

            Bug ID: 95986
           Summary: Partial specialization of class template is not found
                    when class template has NTTP of class type
           Product: gcc
           Version: 10.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bence.kodaj at gmail dot com
  Target Milestone: ---

In the code below I would expect the static assertion __not__ to fail, but it
does.
OS: Ubuntu 18.04.
Godbolt: https://godbolt.org/z/absUyx

---------------------------
#include <type_traits>

template< typename, template< auto... > typename >
struct IsInstantationOf : std::false_type {};

template< template< auto... > typename Template, auto... Arg >
struct IsInstantationOf< Template< Arg... >, Template > : std::true_type {};

template< std::size_t N >
struct StrLiteral {

    constexpr StrLiteral( const char ( & )[ N ] ) {}
};

template< StrLiteral >
struct Template {};

int main()
{
    const auto a = StrLiteral( "a" );

    static_assert( IsInstantationOf< Template< a >, Template >::value );

    return 0;
}
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