C++ PATCH for c++/51925 (ICE with using in template)

commit 08e12669e38d0ef41ebe051b31383906958d24c7
Author: Jason Merrill <jason@redhat.com>
Date:   Sun Jan 22 16:32:53 2012 -0500

    	PR c++/51925
    	* class.c (add_method): Set OVL_USED for using-decls.
    	* tree.c (ovl_scope): New.
    	* cp-tree.h: Declare it.
    	* parser.c (cp_parser_template_name): Use it.
    	* semantics.c (baselink_for_fns): Likewise.
    	* name-lookup.c (set_inherited_value_binding_p): Likewise.

diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index e6f33fe..d654b76 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -1118,6 +1118,8 @@  add_method (tree type, tree method, tree using_decl)
 
   /* Add the new binding.  */
   overload = build_overload (method, current_fns);
+  if (using_decl && TREE_CODE (overload) == OVERLOAD)
+    OVL_USED (overload) = true;
 
   if (conv_p)
     TYPE_HAS_CONVERSION (type) = 1;
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index ccad644..f27755e 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -75,6 +75,7 @@  c-common.h, not after.
       IMPLICIT_CONV_EXPR_DIRECT_INIT (in IMPLICIT_CONV_EXPR)
       TRANSACTION_EXPR_IS_STMT (in TRANSACTION_EXPR)
       CONVERT_EXPR_VBASE_PATH (in CONVERT_EXPR)
+      OVL_ARG_DEPENDENT (in OVERLOAD)
    1: IDENTIFIER_VIRTUAL_P (in IDENTIFIER_NODE)
       TI_PENDING_TEMPLATE_FLAG.
       TEMPLATE_PARMS_FOR_INLINE.
@@ -5679,6 +5680,7 @@  extern tree get_fns				(tree);
 extern tree get_first_fn			(tree);
 extern tree ovl_cons				(tree, tree);
 extern tree build_overload			(tree, tree);
+extern tree ovl_scope				(tree);
 extern bool non_static_member_function_p        (tree);
 extern const char *cxx_printable_name		(tree, int);
 extern const char *cxx_printable_name_translate	(tree, int);
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 5734055..2351342 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -2853,7 +2853,7 @@  set_inherited_value_binding_p (cxx_binding *binding, tree decl,
       tree context;
 
       if (TREE_CODE (decl) == OVERLOAD)
-	context = CP_DECL_CONTEXT (OVL_CURRENT (decl));
+	context = ovl_scope (decl);
       else
 	{
 	  gcc_assert (DECL_P (decl));
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index c4c3ef4..491f48e 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -12722,7 +12722,7 @@  cp_parser_template_name (cp_parser* parser,
      its name; we will look it up again during template instantiation.  */
   if (DECL_FUNCTION_TEMPLATE_P (decl) || !DECL_P (decl))
     {
-      tree scope = CP_DECL_CONTEXT (get_first_fn (decl));
+      tree scope = ovl_scope (decl);
       if (TYPE_P (scope) && dependent_type_p (scope))
 	return identifier;
     }
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index a5a10d0..9019962 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -2807,23 +2807,20 @@  finish_base_specifier (tree base, tree access, bool virtual_p)
 tree
 baselink_for_fns (tree fns)
 {
-  tree fn;
+  tree scope;
   tree cl;
 
   if (BASELINK_P (fns) 
       || error_operand_p (fns))
     return fns;
-  
-  fn = fns;
-  if (TREE_CODE (fn) == TEMPLATE_ID_EXPR)
-    fn = TREE_OPERAND (fn, 0);
-  fn = get_first_fn (fn);
-  if (!DECL_FUNCTION_MEMBER_P (fn))
+
+  scope = ovl_scope (fns);
+  if (!CLASS_TYPE_P (scope))
     return fns;
 
-  cl = currently_open_derived_class (DECL_CONTEXT (fn));
+  cl = currently_open_derived_class (scope);
   if (!cl)
-    cl = DECL_CONTEXT (fn);
+    cl = scope;
   cl = TYPE_BINFO (cl);
   return build_baselink (cl, cl, fns, /*optype=*/NULL_TREE);
 }
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index bf8bc05..cf39800 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -1525,6 +1525,24 @@  build_overload (tree decl, tree chain)
   return ovl_cons (decl, chain);
 }
 
+/* Return the scope where the overloaded functions OVL were found.  */
+
+tree
+ovl_scope (tree ovl)
+{
+  if (TREE_CODE (ovl) == OFFSET_REF
+      || TREE_CODE (ovl) == COMPONENT_REF)
+    ovl = TREE_OPERAND (ovl, 1);
+  if (TREE_CODE (ovl) == BASELINK)
+    return BINFO_TYPE (BASELINK_BINFO (ovl));
+  if (TREE_CODE (ovl) == TEMPLATE_ID_EXPR)
+    ovl = TREE_OPERAND (ovl, 0);
+  /* Skip using-declarations.  */
+  while (TREE_CODE (ovl) == OVERLOAD && OVL_USED (ovl) && OVL_CHAIN (ovl))
+    ovl = OVL_CHAIN (ovl);
+  return CP_DECL_CONTEXT (OVL_CURRENT (ovl));
+}
+
 /* Return TRUE if FN is a non-static member function, FALSE otherwise.
    This function looks into BASELINK and OVERLOAD nodes.  */
 
diff --git a/gcc/testsuite/g++.dg/template/template-id-2.C b/gcc/testsuite/g++.dg/template/template-id-2.C
index 333e33d..d214716 100644
--- a/gcc/testsuite/g++.dg/template/template-id-2.C
+++ b/gcc/testsuite/g++.dg/template/template-id-2.C
@@ -11,7 +11,7 @@  template<> struct A<void>
     template<typename T> void foo()
     {
         A<T> a;
-        a.template foo<int>();	// { dg-error "no member" }
+        a.template foo<int>();	// { dg-error "member" }
     }
 };
 
diff --git a/gcc/testsuite/g++.dg/template/using20.C b/gcc/testsuite/g++.dg/template/using20.C
new file mode 100644
index 0000000..1df9549
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/using20.C
@@ -0,0 +1,18 @@ 
+// PR c++/51925
+
+struct E
+{
+  int e ();
+};
+template <typename T1>
+struct G : public E
+{
+  using E::e;
+  template <int> void e ();
+  void f () { e <0> (); }
+};
+int f(void)
+{
+  G<int> a;
+  a.f();
+}