1 files changed, 25 insertions, 3 deletions
diff --git a/src/dotty/tools/dotc/transform/LambdaLift.scala b/src/dotty/tools/dotc/transform/LambdaLift.scala
index bffc7458e..043c92737 100644
--- a/src/dotty/tools/dotc/transform/LambdaLift.scala
+++ b/src/dotty/tools/dotc/transform/LambdaLift.scala
@@ -384,14 +384,36 @@ class LambdaLift extends MiniPhase with IdentityDenotTransformer { thisTransform
     private def addFreeParams(tree: Tree, proxies: List[Symbol])(implicit ctx: Context, info: TransformerInfo): Tree = proxies match {
       case Nil => tree
       case proxies =>
+        val sym = tree.symbol
         val ownProxies =
-          if (!tree.symbol.isConstructor) proxies
-          else proxies.map(_.copy(owner = tree.symbol, flags = Synthetic | Param))
+          if (!sym.isConstructor) proxies
+          else proxies.map(_.copy(owner = sym, flags = Synthetic | Param))
         val freeParamDefs = ownProxies.map(proxy =>
           transformFollowingDeep(ValDef(proxy.asTerm).withPos(tree.pos)).asInstanceOf[ValDef])
+        def proxyInit(field: Symbol, param: Symbol) =
+          transformFollowingDeep(memberRef(field).becomes(ref(param)))
+
+        /** Map references to proxy fields `this.proxy` to proxy parameters */
+        def mapProxies = new TreeMap {
+          override def transform(tree: Tree)(implicit ctx: Context) = tree match {
+            case Select(This(_), _) if proxies contains tree.symbol =>
+              ref(tree.symbol.subst(proxies, ownProxies))
+            case _ =>
+              super.transform(tree)
+          }
+        }
+
+        /** Initialize proxy fields from proxy parameters and map `rhs` from fields to parameters */
+        def copyParams(rhs: Tree) = {
+          ctx.log(i"copy params ${proxies.map(_.showLocated)}%, %, own = ${ownProxies.map(_.showLocated)}%, %")
+          seq((proxies, ownProxies).zipped.map(proxyInit), mapProxies.transform(rhs))
+        }
+
         tree match {
           case tree: DefDef =>
-            cpy.DefDef(tree)(vparamss = tree.vparamss.map(freeParamDefs ++ _))
+            cpy.DefDef(tree)(
+                vparamss = tree.vparamss.map(freeParamDefs ++ _),
+                rhs = if (sym.isPrimaryConstructor) copyParams(tree.rhs) else tree.rhs)
           case tree: Template =>
             cpy.Template(tree)(body = freeParamDefs ++ tree.body)
         }