We were wrongly checking for nullptr_node rather than nullptr_type. Tested x86_64-pc-linux-gnu, applying to trunk.
commit 325d154928a702116006f1ca40806cee600d6a8b Author: Jason Merrill <ja...@redhat.com> Date: Thu Aug 10 22:05:38 2017 -0700
PR c++/81671 - nullptr_t template parameter * pt.c (convert_nontype_argument): Fix nullptr_t check. diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index 0f899b9..bf1f75d 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -6879,7 +6879,7 @@ convert_nontype_argument (tree type, tree expr, tsubst_flags_t complain) } else if (NULLPTR_TYPE_P (type)) { - if (expr != nullptr_node) + if (!NULLPTR_TYPE_P (TREE_TYPE (expr))) { if (complain & tf_error) error ("%qE is not a valid template argument for type %qT " diff --git a/gcc/testsuite/g++.dg/cpp0x/nullptr39.C b/gcc/testsuite/g++.dg/cpp0x/nullptr39.C new file mode 100644 index 0000000..a34a6af --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/nullptr39.C @@ -0,0 +1,15 @@ +// PR c++/81671 +// { dg-do compile { target c++11 } } + +namespace std { typedef decltype(nullptr) nullptr_t; } + +template<class R, class CB> struct Bar +{}; +template<class R> struct Bar<R, std::nullptr_t> +{ + template<std::nullptr_t> struct Bind { constexpr static int const cb = 0; }; +}; +int foo() +{ + return Bar<int, decltype(nullptr)>::Bind<nullptr>::cb; +}