Move Flatten and RestoreScopes to last group

LambdaLift cannot run at same phase as Flatten, so it's better to move
Flatten one phase later.

Some check files that dependent on the order in which symbols were accessed
needed to be updated.

Author: odersky

compiler/src/dotty/tools/dotc/Compiler.scala

@@ -98,10 +98,10 @@ class Compiler {
       List(new LinkScala2Impls,     // Redirect calls to trait methods defined by Scala 2.x, so that they now go to their implementations
            new LambdaLift,          // Lifts out nested functions to class scope, storing free variables in environments
                                        // Note: in this mini-phase block scopes are incorrect. No phases that rely on scopes should be here
-           new ElimStaticThis,      // Replace `this` references to static objects by global identifiers
-           new Flatten,             // Lift all inner classes to package scope
-           new RestoreScopes),      // Repair scopes rendered invalid by moving definitions in prior phases of the group
-      List(new RenameLifted,        // Renames lifted classes to local numbering scheme
+           new ElimStaticThis),      // Replace `this` references to static objects by global identifiers
+      List(new Flatten,             // Lift all inner classes to package scope
+           new RestoreScopes,      // Repair scopes rendered invalid by moving definitions in prior phases of the group
+           new RenameLifted,        // Renames lifted classes to local numbering scheme
            new TransformWildcards,  // Replace wildcards with default values
            new MoveStatics,         // Move static methods to companion classes
            new ExpandPrivate,       // Widen private definitions accessed from nested classes

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

@@ -16,7 +16,8 @@ class RenameLifted extends MiniPhaseTransform with SymTransformer { thisTransfor
 
   override def phaseName = "renameLifted"
 
-  override def runsAfterGroupsOf: Set[Class[_ <: Phases.Phase]] = Set(classOf[RestoreScopes])
+  // Not clear why this should run after restoreScopes
+  // override def runsAfterGroupsOf: Set[Class[_ <: Phases.Phase]] = Set(classOf[RestoreScopes])
 
   override def treeTransformPhase(implicit ctx: Context, info: TransformerInfo) =
     groupEndPhase

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

@@ -24,6 +24,9 @@ class RestoreScopes extends MiniPhaseTransform with IdentityDenotTransformer { t
 
   override def changesMembers = true // the phase affects scopes, applying tree transformations of previous phases
 
+  override def treeTransformPhase(implicit ctx: Context, info: TransformerInfo) =
+    groupEndPhase
+
   /* Note: We need to wait until we see a package definition because
    * DropEmptyConstructors changes template members when analyzing the
    * enclosing package definitions. So by the time RestoreScopes gets to

tests/run/i2738.check

@@ -1,7 +1,7 @@
 foo
-bar$2
-foo
 bar$1
+foo
+bar$2
 baz
 Test$qux$1$
 baz

tests/run/i3006.check

@@ -1,5 +1,5 @@
-f$3
-f$2
 f$1
 f$2
+f$3
 f$1
+f$2

tests/run/i3006b.check

@@ -1,3 +1,3 @@
-Foo$$init$$$bar$2
 Foo$$init$$$bar$1
+Foo$$init$$$bar$2
 Bar$$init$$$bar$1