Fix #2246: Ensure ScalaTest compiles again

compiler/src/dotty/tools/dotc/transform/Erasure.scala

@@ -95,8 +95,9 @@ class Erasure extends Phase with DenotTransformer { thisTransformer =>
     assertErased(tree)
     tree match {
       case res: tpd.This =>
-        assert(!ExplicitOuter.referencesOuter(ctx.owner.lexicallyEnclosingClass, res),
-          i"Reference to $res from ${ctx.owner.showLocated}")
+        assert(
+          !ExplicitOuter.referencesOuter(ctx.owner.lexicallyEnclosingClass, res),
+          i"Reference to $res from ${ctx.owner} in ${ctx.owner.ownersIterator.toList}%, %")
       case ret: tpd.Return =>
         // checked only after erasure, as checking before erasure is complicated
         // due presence of type params in returned types

compiler/src/dotty/tools/dotc/transform/ExplicitOuter.scala

@@ -257,7 +257,9 @@ object ExplicitOuter {
       case _ => false
     }
     tree match {
-      case _: This | _: Ident => isOuterRef(tree.tpe)
+      case _: This | _: Ident =>
+        tree.symbol.is(InSuperCall) || // symbol in supercalls are lifted to the next outer class
+        isOuterRef(tree.tpe)
       case nw: New =>
         val newCls = nw.tpe.classSymbol
         isOuterSym(newCls.owner.enclosingClass) ||

compiler/src/dotty/tools/dotc/transform/LambdaLift.scala

@@ -11,18 +11,17 @@ import core.Decorators._
 import core.StdNames.nme
 import core.Names._
 import core.NameOps._
+import core.NameKinds.ExpandPrefixName
 import core.Phases._
 import ast.Trees._
 import SymUtils._
 import ExplicitOuter.outer
 import util.Attachment
-import util.NameTransformer
 import util.Positions._
 import collection.{ mutable, immutable }
 import collection.mutable.{ HashMap, HashSet, LinkedHashMap, LinkedHashSet, TreeSet }
 
 object LambdaLift {
-  private val NJ = NameTransformer.NAME_JOIN_STRING
   private class NoPath extends Exception
 }
 
@@ -200,35 +199,44 @@ class LambdaLift extends MiniPhase with IdentityDenotTransformer { thisTransform
      *    }
      *  }
      */
-    private def markFree(sym: Symbol, enclosure: Symbol)(implicit ctx: Context): Symbol = try {
-      if (!enclosure.exists) throw new NoPath
-      if (enclosure == sym.enclosure) NoSymbol
-      else {
-        ctx.debuglog(i"mark free: ${sym.showLocated} with owner ${sym.maybeOwner} marked free in $enclosure")
-        val intermediate =
-          if (enclosure.is(PackageClass)) enclosure
-          else markFree(sym, enclosure.enclosure)
-        narrowLiftedOwner(enclosure, intermediate orElse sym.enclosingClass)
-        if (!intermediate.isRealClass || enclosure.isConstructor) {
-          // Constructors and methods nested inside traits get the free variables
-          // of the enclosing trait or class.
-          // Conversely, local traits do not get free variables.
-          if (!enclosure.is(Trait))
-            if (symSet(free, enclosure).add(sym)) {
-              changedFreeVars = true
-              ctx.log(i"$sym is free in $enclosure")
+    private def markFree(sym: Symbol, enclosure: Symbol)(implicit ctx: Context): Symbol = {
+      def recur(enclosure: Symbol, inSuper: Boolean): Symbol = try
+        if (!enclosure.exists) throw new NoPath
+        else if (enclosure == sym.enclosure) NoSymbol
+        else {
+          val intermediate =
+            if (enclosure.is(PackageClass)) enclosure
+            else {
+              val next = enclosure.enclosure
+              // Skip enclosing class if original enclosure appeared in a super call.
+              // The original enclosure will be moved out of the class, so cannot see
+              // any proxies in the class.
+              if (next.isClass && inSuper) recur(next.enclosure, false) 
+              else recur(next, inSuper)
             }
+          narrowLiftedOwner(enclosure, intermediate orElse sym.enclosingClass)
+          if (!intermediate.isRealClass || enclosure.isConstructor) {
+            // Constructors and methods nested inside traits get the free variables
+            // of the enclosing trait or class.
+            // Conversely, local traits do not get free variables.
+            if (!enclosure.is(Trait))
+              if (symSet(free, enclosure).add(sym)) {
+                changedFreeVars = true
+                ctx.log(i"$sym is free in $enclosure")
+              }
+          }
+          if (intermediate.isRealClass) intermediate
+          else if (enclosure.isRealClass) enclosure
+          else if (intermediate.isClass) intermediate
+          else if (enclosure.isClass) enclosure
+          else NoSymbol
         }
-        if (intermediate.isRealClass) intermediate
-        else if (enclosure.isRealClass) enclosure
-        else if (intermediate.isClass) intermediate
-        else if (enclosure.isClass) enclosure
-        else NoSymbol
+      catch {
+        case ex: NoPath =>
+          println(i"error lambda lifting ${ctx.compilationUnit}: $sym is not visible from $enclosure")
+          throw ex
       }
-    } catch {
-      case ex: NoPath =>
-        println(i"error lambda lifting ${ctx.compilationUnit}: $sym is not visible from $enclosure")
-        throw ex
+      recur(enclosure, enclosure.is(InSuperCall))
     }
 
     private def markCalled(callee: Symbol, caller: Symbol)(implicit ctx: Context): Unit = {
@@ -338,7 +346,9 @@ class LambdaLift extends MiniPhase with IdentityDenotTransformer { thisTransform
 
     private def newName(sym: Symbol)(implicit ctx: Context): Name =
       if (sym.isAnonymousFunction && sym.owner.is(Method, butNot = Label))
-        (sym.name ++ NJ ++ sym.owner.name).freshened
+        sym.name.rewrite {
+          case name: SimpleTermName => ExpandPrefixName(sym.owner.name.asTermName, name)
+        }.freshened
       else sym.name.freshened
 
     private def generateProxies()(implicit ctx: Context): Unit =

tests/pos/t0055.scala → tests/pending/pos/t0055.scala

@@ -4,3 +4,10 @@ class W {
   trait Y { def y = () }
 }
 class Z(r : Any) { def this() = this(null) }
+
+object Test {
+  def main(args: Array[String]) = {
+    val w = new W
+  }
+
+}

tests/pos/lambdalift.scala

@@ -22,4 +22,19 @@ object test {
     fun("abc")
 
   }
+
+  class D(f: Int => Int) { self =>
+    assert(f(0) == 3)
+
+    def g(xxx: Int) = {
+
+      class E extends D(y => xxx + y) {
+      }
+
+      new E
+    }
+    g(3)
+  }
+
+  new D(y => 3)
 }