re PR c++/72707 (local anonymous union member hides names in the same scope)

	PR c++/72707
	* name-lookup.c (pushdecl_maybe_friend_1): Do check shadowing of
	artificial x if it is an anonymous union variable.

	* g++.dg/warn/Wshadow-12.C: New test.

From-SVN: r243877

gcc/cp/ChangeLog

 2016-12-21  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/72707
+	* name-lookup.c (pushdecl_maybe_friend_1): Do check shadowing of
+	artificial x if it is an anonymous union variable.
+
 	PR bootstrap/78817
 	* typeck.c (cp_build_function_call_vec): If check_function_arguments
 	returns true, set TREE_NO_WARNING on CALL_EXPR.

gcc/cp/name-lookup.c

@@ -1111,8 +1111,10 @@ pushdecl_maybe_friend_1 (tree x, bool is_friend)
                                || TREE_CODE (x) == TYPE_DECL)))
                    /* Don't check for internally generated vars unless
                       it's an implicit typedef (see create_implicit_typedef
-                      in decl.c).  */
-		   && (!DECL_ARTIFICIAL (x) || DECL_IMPLICIT_TYPEDEF_P (x)))
+                      in decl.c) or anonymous union variable.  */
+		   && (!DECL_ARTIFICIAL (x)
+		       || DECL_IMPLICIT_TYPEDEF_P (x)
+		       || (VAR_P (x) && DECL_ANON_UNION_VAR_P (x))))
 	    {
 	      bool nowarn = false;
 

gcc/testsuite/ChangeLog

+2016-12-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/72707
+	* g++.dg/warn/Wshadow-12.C: New test.
+
 2016-12-21  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR rtl-optimization/78580

gcc/testsuite/g++.dg/warn/Wshadow-12.C

+// PR c++/72707
+// { dg-do compile }
+
+void
+foo (double x)
+{
+  union { int x; };	// { dg-error "shadows a parameter" }
+  x = 0;
+}