Index: src/GenPoly/Specialize.cc
===================================================================
--- src/GenPoly/Specialize.cc	(revision 9939dc312f9fd40e9451c8c3c70ac5e68e233d16)
+++ src/GenPoly/Specialize.cc	(revision a8b87d3db4fd7828fac5029e592eb07f8b87bcb6)
@@ -247,4 +247,5 @@
 			structureArg( (*actualBegin)->get_type(), argBegin, argEnd, back_inserter( appExpr->get_args() ) );
 		}
+		assertf( argBegin == argEnd, "Did not structure all arguments." );
 
 		appExpr->env = TypeSubstitution::newFromExpr( appExpr, env );