Index: src/InitTweak/FixInit.cc
===================================================================
--- src/InitTweak/FixInit.cc	(revision 09c72d5b6600e44f191c62a215942254161db898)
+++ src/InitTweak/FixInit.cc	(revision b8baa37eb2d4983aa6519224b93c9a92306453af)
@@ -187,5 +187,5 @@
 		};
 
-		class FixCopyCtors final : public WithStmtsToAdd, public WithShortCircuiting, public WithVisitorRef<FixCopyCtors> {
+		class FixCopyCtors final : public WithStmtsToAdd, public WithShortCircuiting, public WithVisitorRef<FixCopyCtors>, public WithTypeSubstitution {
 		  public:
 			FixCopyCtors( UnqCount & unqCount ) : unqCount( unqCount ){}
@@ -636,5 +636,5 @@
 				// take relevant bindings from environment
 				assert( ! dtor->env );
-				dtor->env =  TypeSubstitution::newFromExpr( dtor, impCpCtorExpr->env );
+				dtor->env =  maybeClone( env );
 				stmtsToAddAfter.push_back( new ExprStmt( dtor ) );
 			} // for