Index: src/Tuples/TupleExpansion.cc
===================================================================
--- src/Tuples/TupleExpansion.cc	(revision 7abee383f06a7fe5690784e7676edcdf68ff7660)
+++ src/Tuples/TupleExpansion.cc	(revision b1d3ee1e84145955b10068d160898445cc59b4a6)
@@ -58,5 +58,5 @@
 		};
 
-		struct TupleTypeReplacer : public WithDeclsToAdd, public WithGuards, public WithTypeSubstitution {
+		struct TupleTypeReplacer : public WithDeclsToAdd, public WithGuards, public WithConstTypeSubstitution {
 			Type * postmutate( TupleType * tupleType );