re PR c++/52008 ([Core/1495] ICE when adding partial specialization for…

re PR c++/52008 ([Core/1495] ICE when adding partial specialization for variadic-templated structure)

	PR c++/52008
	* pt.c (process_partial_specialization): Complain about a partial
	specialization with fewer args than primary template parms.

From-SVN: r186521

gcc/cp/ChangeLog

 2012-04-16  Jason Merrill  <jason@redhat.com>
 
+	PR c++/52008
+	* pt.c (process_partial_specialization): Complain about a partial
+	specialization with fewer args than primary template parms.
+
 	PR c++/50830
 	* pt.c (convert_template_argument): Handle template template
 	argument packs.

gcc/cp/pt.c

@@ -4376,6 +4376,18 @@ process_partial_specialization (tree decl)
 						   (maintmpl)))))
     error ("partial specialization %qT does not specialize any template arguments", type);
 
+  /* A partial specialization that replaces multiple parameters of the
+     primary template with a pack expansion is less specialized for those
+     parameters.  */
+  if (nargs < DECL_NTPARMS (maintmpl))
+    {
+      error ("partial specialization is not more specialized than the "
+	     "primary template because it replaces multiple parameters "
+	     "with a pack expansion");
+      inform (DECL_SOURCE_LOCATION (maintmpl), "primary template here");
+      return decl;
+    }
+
   /* [temp.class.spec]
 
      A partially specialized non-type argument expression shall not

gcc/testsuite/ChangeLog

 2012-04-16  Jason Merrill  <jason@redhat.com>
 
+	PR c++/52008
+	* g++.dg/cpp0x/variadic130.C: New.
+
 	PR c++/50830
 	* g++.dg/cpp0x/variadic129.C: New.
 

gcc/testsuite/g++.dg/cpp0x/variadic130.C

+// PR c++/52008
+// { dg-do compile { target c++11 } }
+
+template <int I, typename T, typename... Ts>
+struct A;
+
+template<typename... Ts>
+struct A<0, Ts...>;		// { dg-error "not more specialized" }