PR c++/71569 - ICE with redundant args on member variable template.

	* decl.c (start_decl): Handle partial specialization of member
	variable template.
	* pt.c (determine_specialization): Allow partial specialization
	of member variable template without specializing enclosing class.
	(process_partial_specialization): Improve error message.

Co-Authored-By: Alexandre Oliva <aoliva@redhat.com>

From-SVN: r258102

gcc/cp/ChangeLog

+2018-03-01  Jason Merrill  <jason@redhat.com>
+	    Alexandre Oliva <aoliva@redhat.com>
+
+	PR c++/71569 - ICE with redundant args on member variable template.
+	* decl.c (start_decl): Handle partial specialization of member
+	variable template.
+	* pt.c (determine_specialization): Allow partial specialization
+	of member variable template without specializing enclosing class.
+	(process_partial_specialization): Improve error message.
+
 2018-02-28  Jason Merrill  <jason@redhat.com>
 
 	PR c++/71784 - ICE with ref-qualifier and explicit specialization.

gcc/cp/decl.c

@@ -5080,19 +5080,17 @@ start_decl (const cp_declarator *declarator,
 	  if (field == NULL_TREE
 	      || !(VAR_P (field) || variable_template_p (field)))
 	    error ("%q+#D is not a static data member of %q#T", decl, context);
+	  else if (variable_template_p (field)
+		   && (DECL_LANG_SPECIFIC (decl)
+		       && DECL_TEMPLATE_SPECIALIZATION (decl)))
+	    /* OK, specialization was already checked.  */;
 	  else if (variable_template_p (field) && !this_tmpl)
 	    {
-	      if (DECL_LANG_SPECIFIC (decl)
-		  && DECL_TEMPLATE_SPECIALIZATION (decl))
-		/* OK, specialization was already checked.  */;
-	      else
-		{
-		  error_at (DECL_SOURCE_LOCATION (decl),
-			    "non-member-template declaration of %qD", decl);
-		  inform (DECL_SOURCE_LOCATION (field), "does not match "
-			  "member template declaration here");
-		  return error_mark_node;
-		}
+	      error_at (DECL_SOURCE_LOCATION (decl),
+			"non-member-template declaration of %qD", decl);
+	      inform (DECL_SOURCE_LOCATION (field), "does not match "
+		      "member template declaration here");
+	      return error_mark_node;
 	    }
 	  else
 	    {

gcc/cp/pt.c

@@ -2060,7 +2060,8 @@ determine_specialization (tree template_id,
   /* We shouldn't be specializing a member template of an
      unspecialized class template; we already gave an error in
      check_specialization_scope, now avoid crashing.  */
-  if (template_count && DECL_CLASS_SCOPE_P (decl)
+  if (!VAR_P (decl)
+      && template_count && DECL_CLASS_SCOPE_P (decl)
       && template_class_depth (DECL_CONTEXT (decl)) > 0)
     {
       gcc_assert (errorcount);
@@ -4840,10 +4841,13 @@ process_partial_specialization (tree decl)
     {
       if (!flag_concepts)
         error ("partial specialization %q+D does not specialize "
-	       "any template arguments", decl);
+	       "any template arguments; to define the primary template, "
+	       "remove the template argument list", decl);
       else
         error ("partial specialization %q+D does not specialize any "
-	       "template arguments and is not more constrained than", decl);
+	       "template arguments and is not more constrained than "
+	       "the primary template; to define the primary template, "
+	       "remove the template argument list", decl);
       inform (DECL_SOURCE_LOCATION (maintmpl), "primary template here");
     }
 

gcc/testsuite/g++.dg/cpp1y/var-templ58.C

+// PR c++/71569
+// { dg-do compile { target c++14 } }
+
+template <class T>
+struct A {
+  template <class U>
+  static const U u;
+};
+
+template <class T>
+template <class U>
+const U A<T>::u<U> = 0;	// { dg-error "does not specialize" }

gcc/testsuite/g++.dg/cpp1y/var-templ58a.C

+// PR c++/71569
+// { dg-do compile { target c++14 } }
+
+template <class T>
+struct A {
+  template <class U>
+  static const U u;
+};
+
+template <class T>
+template <class U>
+const U* A<T>::u<U*> = 0;
+
+const int *p = A<char>::u<int*>;