re PR c++/49045 ([C++0x] unexpected "different exception specifier" error with noexcept)

	PR c++/49045
	Core 1321
	* tree.c (dependent_name): New.
	(cp_tree_equal): Two calls with the same dependent name are
	equivalent even if the overload sets are different.

From-SVN: r177998

gcc/cp/ChangeLog

 2011-08-23  Jason Merrill  <jason@redhat.com>
 
+	PR c++/49045
+	Core 1321
+	* tree.c (dependent_name): New.
+	(cp_tree_equal): Two calls with the same dependent name are
+	equivalent even if the overload sets are different.
+
+2011-08-23  Jason Merrill  <jason@redhat.com>
+
 	* tree.c (build_target_expr): Set TREE_CONSTANT on
 	literal TARGET_EXPR if the value is constant.
 	* typeck2.c (build_functional_cast): Don't set it here.

gcc/cp/tree.c

@@ -1450,6 +1450,21 @@ is_overloaded_fn (tree x)
 	   || TREE_CODE (x) == OVERLOAD);
 }
 
+/* X is the CALL_EXPR_FN of a CALL_EXPR.  If X represents a dependent name
+   (14.6.2), return the IDENTIFIER_NODE for that name.  Otherwise, return
+   NULL_TREE.  */
+
+static tree
+dependent_name (tree x)
+{
+  if (TREE_CODE (x) == IDENTIFIER_NODE)
+    return x;
+  if (TREE_CODE (x) != COMPONENT_REF
+      && is_overloaded_fn (x))
+    return DECL_NAME (get_first_fn (x));
+  return NULL_TREE;
+}
+
 /* Returns true iff X is an expression for an overloaded function
    whose type cannot be known without performing overload
    resolution.  */
@@ -2187,7 +2202,12 @@ cp_tree_equal (tree t1, tree t2)
       {
 	tree arg1, arg2;
 	call_expr_arg_iterator iter1, iter2;
-	if (!cp_tree_equal (CALL_EXPR_FN (t1), CALL_EXPR_FN (t2)))
+	/* Core 1321: dependent names are equivalent even if the
+	   overload sets are different.  */
+	tree name1 = dependent_name (CALL_EXPR_FN (t1));
+	tree name2 = dependent_name (CALL_EXPR_FN (t2));
+	if (!(name1 && name2 && name1 == name2)
+	    && !cp_tree_equal (CALL_EXPR_FN (t1), CALL_EXPR_FN (t2)))
 	  return false;
 	for (arg1 = first_call_expr_arg (t1, &iter1),
 	       arg2 = first_call_expr_arg (t2, &iter2);

gcc/testsuite/ChangeLog

 2011-08-23  Jason Merrill  <jason@redhat.com>
 
+	PR c++/49045
+	Core 1321
+	* g++.dg/cpp0x/overload2.C: New.
+
+2011-08-23  Jason Merrill  <jason@redhat.com>
+
 	Core 903
 	* g++.dg/cpp0x/constexpr-nullptr.C: Now ill-formed.
 

gcc/testsuite/g++.dg/cpp0x/overload2.C

+// Core 1321
+// { dg-options -std=c++0x }
+// Two dependent names are equivalent even if the overload sets found by
+// phase 1 lookup are different.  Merging them keeps the earlier set.
+
+int g1(int);
+template <class T> decltype(g1(T())) f1();
+int g1();
+template <class T> decltype(g1(T())) f1()
+{ return g1(T()); }
+int i1 = f1<int>();	    // OK, g1(int) was declared before the first f1
+
+template <class T> decltype(g2(T())) f2();
+int g2(int);
+template <class T> decltype(g2(T())) f2() // { dg-error "g2. was not declared" }
+{ return g2(T()); }
+int i2 = f2<int>();			  // { dg-error "no match" }
+
+int g3();
+template <class T> decltype(g3(T())) f3();
+int g3(int);
+template <class T> decltype(g3(T())) f3() // { dg-error "too many arguments" }
+{ return g3(T()); }
+int i3 = f3<int>();			  // { dg-error "no match" }