re PR c++/31749 (ICE with invalid redeclaration of builtin)

	PR c++/31749

	gcc/cp/
	* name-lookup.c (do_nonmember_using_decl): Shift implicit type
	declarations into appropriate slots for comparison.  Fix type
	comparison.

	gcc/testsuite/
	* g++.dg/lookup/builtin3.C: New test.
	* g++.dg/lookup/builtin4.C: New test.
	* g++.dg/lookup/using19.C: New test.

From-SVN: r127600

gcc/cp/ChangeLog

+2007-08-17  Ollie Wild  <aaw@google.com>
+
+	PR c++/31749
+	* name-lookup.c (do_nonmember_using_decl): Shift implicit type
+	declarations into appropriate slots for comparison.  Fix type
+	comparison.
+
 2007-08-17  Paolo Carlini  <pcarlini@suse.de>
 
 	PR c++/32112

gcc/cp/name-lookup.c

@@ -2099,6 +2099,20 @@ do_nonmember_using_decl (tree scope, tree name, tree oldval, tree oldtype,
       return;
     }
 
+  /* Shift the old and new bindings around so we're comparing class and
+     enumeration names to each other.  */
+  if (oldval && DECL_IMPLICIT_TYPEDEF_P (oldval))
+    {
+      oldtype = oldval;
+      oldval = NULL_TREE;
+    }
+
+  if (decls.value && DECL_IMPLICIT_TYPEDEF_P (decls.value))
+    {
+      decls.type = decls.value;
+      decls.value = NULL_TREE;
+    }
+
   /* It is impossible to overload a built-in function; any explicit
      declaration eliminates the built-in declaration.  So, if OLDVAL
      is a built-in, then we can just pretend it isn't there.  */
@@ -2108,14 +2122,15 @@ do_nonmember_using_decl (tree scope, tree name, tree oldval, tree oldtype,
       && !DECL_HIDDEN_FRIEND_P (oldval))
     oldval = NULL_TREE;
 
+  if (decls.value)
+    {
       /* Check for using functions.  */
-  if (decls.value && is_overloaded_fn (decls.value))
+      if (is_overloaded_fn (decls.value))
 	{
 	  tree tmp, tmp1;
 
 	  if (oldval && !is_overloaded_fn (oldval))
 	    {
-	  if (!DECL_IMPLICIT_TYPEDEF_P (oldval))
 	      error ("%qD is already declared in this scope", name);
 	      oldval = NULL_TREE;
 	    }
@@ -2189,6 +2204,9 @@ do_nonmember_using_decl (tree scope, tree name, tree oldval, tree oldtype,
 	  if (oldval && !decls_match (*newval, oldval))
 	    error ("%qD is already declared in this scope", name);
 	}
+    }
+  else
+    *newval = oldval;
 
   if (decls.type && TREE_CODE (decls.type) == TREE_LIST)
     {
@@ -2198,12 +2216,15 @@ do_nonmember_using_decl (tree scope, tree name, tree oldval, tree oldtype,
   else
     {
       *newtype = decls.type;
-      if (oldtype && *newtype && !same_type_p (oldtype, *newtype))
-	{
-	  error ("using declaration %qD introduced ambiguous type %qT",
-		 name, oldtype);
-	  return;
+      if (oldtype && *newtype && !decls_match (oldtype, *newtype))
+	error ("%qD is already declared in this scope", name);
     }
+
+    /* If *newval is empty, shift any class or enumeration name down.  */
+    if (!*newval)
+      {
+	*newval = *newtype;
+	*newtype = NULL_TREE;
       }
 }
 

gcc/testsuite/ChangeLog

+2007-08-17  Ollie Wild  <aaw@google.com>
+
+	PR c++/31749
+	* g++.dg/lookup/builtin3.C: New test.
+	* g++.dg/lookup/builtin4.C: New test.
+	* g++.dg/lookup/using19.C: New test.
+
 2007-08-17  Paolo Carlini  <pcarlini@suse.de>
 
 	PR c++/32190

gcc/testsuite/g++.dg/lookup/builtin3.C

+// Copyright (C) 2007 Free Software Foundation
+// Contributed by Ollie Wild <aaw@google.com>
+// Origin: Volker Reichelt <reichelt@gcc.gnu.org>
+// { dg-do compile }
+
+// PR 31749: ICE with redeclaration of builtin
+
+namespace std
+{
+  union abort;
+}
+
+void abort();
+
+using std::abort;

gcc/testsuite/g++.dg/lookup/builtin4.C

+// Copyright (C) 2007 Free Software Foundation
+// Contributed by Ollie Wild <aaw@google.com>
+// Origin: Volker Reichelt <reichelt@gcc.gnu.org>
+// { dg-do compile }
+
+// PR 31749: ICE with redeclaration of builtin
+
+namespace std
+{
+  union abort;
+}
+
+union abort;
+
+using std::abort; // { dg-error "" }

gcc/testsuite/g++.dg/lookup/using19.C

+// Copyright (C) 2007 Free Software Foundation
+// Contributed by Ollie Wild <aaw@google.com>
+// { dg-do compile }
+
+
+// C++ Standard, 7.3.3, clause 10:
+// "Since a using-declaration is a declaration, the restrictions on
+// declarations of the same name in the same declarative region (3.3) also
+// apply to using-declarations."
+
+namespace M
+{
+  union A;
+  void B();
+}
+
+void A();
+union B;
+
+using M::A;
+using M::B;