re PR c++/84092 (ICE on C++14 code with variable template: in…

re PR c++/84092 (ICE on C++14 code with variable template: in build_qualified_name, at cp/tree.c:2043)

/cp
2018-01-31  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/84092
	* semantics.c (finish_qualified_id_expr): When handling an
	UNBOUND_CLASS_TEMPLATE only adjust qualifying_class and expr.

/testsuite
2018-01-31  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/84092
	* g++.dg/cpp1y/var-templ57.C: New.

From-SVN: r257242

gcc/cp/ChangeLog

+2018-01-31  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/84092
+	* semantics.c (finish_qualified_id_expr): When handling an
+	UNBOUND_CLASS_TEMPLATE only adjust qualifying_class and expr.
+
 2018-01-31  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/84138

gcc/cp/semantics.c

@@ -2001,12 +2001,12 @@ finish_qualified_id_expr (tree qualifying_class,
   if (template_p)
     {
       if (TREE_CODE (expr) == UNBOUND_CLASS_TEMPLATE)
-	/* cp_parser_lookup_name thought we were looking for a type,
-	   but we're actually looking for a declaration.  */
-	expr = build_qualified_name (/*type*/NULL_TREE,
-				     TYPE_CONTEXT (expr),
-				     TYPE_IDENTIFIER (expr),
-				     /*template_p*/true);
+	{
+	  /* cp_parser_lookup_name thought we were looking for a type,
+	     but we're actually looking for a declaration.  */
+	  qualifying_class = TYPE_CONTEXT (expr);
+	  expr = TYPE_IDENTIFIER (expr);
+	}
       else
 	check_template_keyword (expr);
     }

gcc/testsuite/ChangeLog

+2018-01-31  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/84092
+	* g++.dg/cpp1y/var-templ57.C: New.
+
 2018-01-31  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/84138

gcc/testsuite/g++.dg/cpp1y/var-templ57.C

+// PR c++/84092
+// { dg-do compile { target c++14 } }
+
+template < typename T > int a (T::template b);