Index: src/CodeGen/CodeGenerator.cc
===================================================================
--- src/CodeGen/CodeGenerator.cc	(revision e8032b011e6d5bdc74f9cb82d480387e1e6ecee2)
+++ src/CodeGen/CodeGenerator.cc	(revision cb4c607c4212505e28b756e33cdf1030b6bd93e8)
@@ -455,5 +455,5 @@
 
 	void CodeGenerator::visit( UntypedOffsetofExpr *offsetofExpr ) {
-		assert( false );
+		assert( false && "UntypedOffsetofExpr should not reach code generation" );
 	}
 
@@ -464,4 +464,8 @@
 		output << ", " << mangleName( offsetofExpr->get_member() );
 		output << ")";
+	}
+
+	void CodeGenerator::visit( OffsetPackExpr *offsetPackExpr ) {
+		assert( false && "OffsetPackExpr should not reach code generation" );
 	}
   
Index: src/CodeGen/CodeGenerator.h
===================================================================
--- src/CodeGen/CodeGenerator.h	(revision e8032b011e6d5bdc74f9cb82d480387e1e6ecee2)
+++ src/CodeGen/CodeGenerator.h	(revision cb4c607c4212505e28b756e33cdf1030b6bd93e8)
@@ -65,4 +65,5 @@
 		virtual void visit( UntypedOffsetofExpr *offsetofExpr );
 		virtual void visit( OffsetofExpr *offsetofExpr );
+		virtual void visit( OffsetPackExpr *offsetPackExpr );
 		virtual void visit( LogicalExpr *logicalExpr );
 		virtual void visit( ConditionalExpr *conditionalExpr );