Index: src/InitTweak/FixInit.cc
===================================================================
--- src/InitTweak/FixInit.cc	(revision dd05e12d91f94668b101255655342bfd9b8f4486)
+++ src/InitTweak/FixInit.cc	(revision bd5cf7c99843603f89e5d97ee6f2f825f9176af5)
@@ -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