PR c++/91923 - failure-to-SFINAE with class type NTTP in C++17.

	* pt.c (invalid_nontype_parm_type_p): Only emit errors when
	tf_error.

	* g++.dg/cpp0x/nontype5.C: New test.

From-SVN: r276248

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 8ea2a84..895ebd9 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2019-09-28  Marek Polacek  <polacek@redhat.com>
+
+       PR c++/91923 - failure-to-SFINAE with class type NTTP in C++17.
+       * pt.c (invalid_nontype_parm_type_p): Only emit errors when
+       tf_error.
+
 2019-09-27  Jakub Jelinek  <jakub@redhat.com>
 
        PR c++/88203

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 5a2dfbb..44b3618 100644 (file)
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -25232,8 +25232,9 @@ invalid_nontype_parm_type_p (tree type, tsubst_flags_t complain)
     {
       if (cxx_dialect < cxx2a)
        {
-         error ("non-type template parameters of class type only available "
-                "with %<-std=c++2a%> or %<-std=gnu++2a%>");
+         if (complain & tf_error)
+           error ("non-type template parameters of class type only available "
+                  "with %<-std=c++2a%> or %<-std=gnu++2a%>");
          return true;
        }
       if (dependent_type_p (type))

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8fadb03..617fc99 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-09-28  Marek Polacek  <polacek@redhat.com>
+
+       PR c++/91923 - failure-to-SFINAE with class type NTTP in C++17.
+       * g++.dg/cpp0x/nontype5.C: New test.
+
 2019-09-28  Alan Modra  <amodra@gmail.com>
 
        PR testsuite/91676

diff --git a/gcc/testsuite/g++.dg/cpp0x/nontype5.C b/gcc/testsuite/g++.dg/cpp0x/nontype5.C
new file mode 100644 (file)
index 0000000..c311345
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/nontype5.C
@@ -0,0 +1,17 @@
+// PR c++/91923 - failure-to-SFINAE with class type NTTP in C++17.
+// { dg-do compile { target c++11 } }
+
+template<typename T>
+constexpr bool is_integral_(...) {
+    return false;
+}
+template<typename T, T = 1>
+constexpr bool is_integral_(long) {
+    return true;
+}
+
+static_assert(is_integral_<int>(42), "");
+static_assert(!is_integral_<void>(42), "");
+
+struct S {};
+static_assert(!is_integral_<S>(42), "");