Index: src/Tuples/TupleExpansion.cc
===================================================================
--- src/Tuples/TupleExpansion.cc	(revision 7abee383f06a7fe5690784e7676edcdf68ff7660)
+++ src/Tuples/TupleExpansion.cc	(revision 9e1d48503286c2f21bf3f599590920efc8b02293)
@@ -58,5 +58,5 @@
 		};
 
-		struct TupleTypeReplacer : public WithDeclsToAdd, public WithGuards, public WithTypeSubstitution {
+		struct TupleTypeReplacer : public WithDeclsToAdd, public WithGuards, public WithConstTypeSubstitution {
 			Type * postmutate( TupleType * tupleType );