re PR c++/66684 (ICE in merge_exception_specifiers, at cp/typeck2.c:2114)

	PR c++/66684
	* typeck2.c (merge_exception_specifiers): Allow different
	noexcept-specifiers if we've had errors.

From-SVN: r225086

gcc/cp/ChangeLog

 2015-06-26  Jason Merrill  <jason@redhat.com>
 
+	PR c++/66684
+	* typeck2.c (merge_exception_specifiers): Allow different
+	noexcept-specifiers if we've had errors.
+
 	PR c++/66255
 	* pt.c (check_unstripped_args): Split out from...
 	(retrieve_specialization): ...here.  Allow typedefs in the type of

gcc/cp/typeck2.c

@@ -2112,6 +2112,7 @@ merge_exception_specifiers (tree list, tree add)
     return add;
   noex = TREE_PURPOSE (list);
   gcc_checking_assert (!TREE_PURPOSE (add)
+		       || errorcount
 		       || cp_tree_equal (noex, TREE_PURPOSE (add)));
 
   /* Combine the dynamic-exception-specifiers, if any.  */

gcc/testsuite/g++.dg/cpp0x/noexcept28.C

+// PR c++/66684
+// { dg-do compile { target c++11 } }
+
+template<typename T>
+struct traits
+{
+  static constexpr bool foo() { return sizeof(T) > 1; }
+  static constexpr bool bar() { return sizeof(T) > 1; }
+};
+
+template<typename T>
+struct X
+{
+  X& operator=(X&&) noexcept(traits<T>::foo());
+};
+
+template<typename T>
+  X<T>&
+  X<T>::operator=(X&&) noexcept(traits<T>::foo() && traits<T>::bar()) // { dg-error "different exception" }
+  { return *this; }