Index: src/GenPoly/InstantiateGeneric.cc
===================================================================
--- src/GenPoly/InstantiateGeneric.cc	(revision 27aca84c89a0c7286b8f204457ed8b73e6f31156)
+++ src/GenPoly/InstantiateGeneric.cc	(revision 773db6560a2d9f12276c8be70b8011a7799f23c0)
@@ -168,5 +168,5 @@
 
 	/// Mutator pass that replaces concrete instantiations of generic types with actual struct declarations, scoped appropriately
-	struct GenericInstantiator final : public WithTypeSubstitution, public WithDeclsToAdd, public WithVisitorRef<GenericInstantiator>, public WithGuards {
+	struct GenericInstantiator final : public WithConstTypeSubstitution, public WithDeclsToAdd, public WithVisitorRef<GenericInstantiator>, public WithGuards {
 		/// Map of (generic type, parameter list) pairs to concrete type instantiations
 		InstantiationMap< AggregateDecl, AggregateDecl > instantiations;