Merge pull request #3350 from dotty-staging/change-transform-phases-3

Run all miniphase transforms at group end

Author: odersky

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

@@ -53,15 +53,15 @@ class Compiler {
            new ElimJavaPackages),   // Eliminate syntactic references to Java packages
       List(new CheckStatic,         // Check restrictions that apply to @static members
            new ElimRepeated,        // Rewrite vararg parameters and arguments
-           new RefChecks,           // Various checks mostly related to abstract members and overriding
            new NormalizeFlags,      // Rewrite some definition flags
            new ExtensionMethods,    // Expand methods of value classes with extension methods
            new ExpandSAMs,          // Expand single abstract method closures to anonymous classes
            new TailRec,             // Rewrite tail recursion to loops
            new ByNameClosures,      // Expand arguments to by-name parameters to closures
            new LiftTry,             // Put try expressions that might execute on non-empty stacks into their own methods
            new HoistSuperArgs,      // Hoist complex arguments of supercalls to enclosing scope
-           new ClassOf),            // Expand `Predef.classOf` calls.
+           new ClassOf,            // Expand `Predef.classOf` calls.
+           new RefChecks),           // Various checks mostly related to abstract members and overriding
       List(new TryCatchPatterns,    // Compile cases in try/catch
            new PatternMatcher,      // Compile pattern matches
            new ExplicitOuter,       // Add accessors to outer classes from nested ones.
@@ -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/ast/tpd.scala

@@ -656,26 +656,27 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     /** After phase `trans`, set the owner of every definition in this tree that was formerly
      *  owner by `from` to `to`.
      */
-    def changeOwnerAfter(from: Symbol, to: Symbol, trans: DenotTransformer)(implicit ctx: Context): ThisTree = {
-      assert(ctx.phase == trans.next)
-      val traverser = new TreeTraverser {
-        def traverse(tree: Tree)(implicit ctx: Context) = tree match {
-          case tree: DefTree =>
-            val sym = tree.symbol
-            val prevDenot = sym.denot(ctx.withPhase(trans))
-            if (prevDenot.effectiveOwner == from.skipWeakOwner) {
-              val d = sym.copySymDenotation(owner = to)
-              d.installAfter(trans)
-              d.transformAfter(trans, d => if (d.owner eq from) d.copySymDenotation(owner = to) else d)
-            }
-            if (sym.isWeakOwner) traverseChildren(tree)
-          case _ =>
-            traverseChildren(tree)
+    def changeOwnerAfter(from: Symbol, to: Symbol, trans: DenotTransformer)(implicit ctx: Context): ThisTree =
+      if (ctx.phase == trans.next) {
+        val traverser = new TreeTraverser {
+          def traverse(tree: Tree)(implicit ctx: Context) = tree match {
+            case tree: DefTree =>
+              val sym = tree.symbol
+              val prevDenot = sym.denot(ctx.withPhase(trans))
+              if (prevDenot.effectiveOwner == from.skipWeakOwner) {
+                val d = sym.copySymDenotation(owner = to)
+                d.installAfter(trans)
+                d.transformAfter(trans, d => if (d.owner eq from) d.copySymDenotation(owner = to) else d)
+              }
+              if (sym.isWeakOwner) traverseChildren(tree)
+            case _ =>
+              traverseChildren(tree)
+          }
         }
+        traverser.traverse(tree)
+        tree
       }
-      traverser.traverse(tree)
-      tree
-    }
+      else changeOwnerAfter(from, to, trans)(ctx.withPhase(trans.next))
 
     /** A select node with the given selector name and a computed type */
     def select(name: Name)(implicit ctx: Context): Select =

compiler/src/dotty/tools/dotc/core/Phases.scala

@@ -298,11 +298,6 @@ object Phases {
      */
     def checkPostCondition(tree: tpd.Tree)(implicit ctx: Context): Unit = ()
 
-    /** If set, allow missing or superfluous arguments in applications
-     *  and type applications.
-     */
-    def relaxedTyping: Boolean = false
-
     /** Is this phase the standard typerphase? True for FrontEnd, but
      *  not for other first phases (such as FromTasty). The predicate
      *  is tested in some places that perform checks and corrections. It's

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

@@ -91,7 +91,7 @@ class CapturedVars extends MiniPhase with IdentityDenotTransformer { thisTransfo
     }
 
     override def prepareForValDef(vdef: ValDef)(implicit ctx: Context) = {
-      val sym = vdef.symbol
+      val sym = vdef.symbol(ctx.withPhase(thisTransform))
       if (captured contains sym) {
         val newd = sym.denot(ctx.withPhase(thisTransform)).copySymDenotation(
           info = refClass(sym.info.classSymbol, sym.hasAnnotation(defn.VolatileAnnot)).typeRef,
@@ -119,7 +119,7 @@ class CapturedVars extends MiniPhase with IdentityDenotTransformer { thisTransfo
     override def transformIdent(id: Ident)(implicit ctx: Context, info: TransformerInfo): Tree = {
       val vble = id.symbol
       if (captured(vble))
-        (id select nme.elem).ensureConforms(vble.denot(ctx.withPhase(thisTransform)).info)
+        id.select(nme.elem).ensureConforms(vble.denot(ctx.withPhase(thisTransform)).info)
       else id
     }
 

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

@@ -47,7 +47,8 @@ class ElimByName extends TransformByNameApply with InfoTransformer { thisTransfo
 
   /** Map `tree` to `tree.apply()` is `ftree` was of ExprType and becomes now a function */
   private def applyIfFunction(tree: Tree, ftree: Tree)(implicit ctx: Context) =
-    if (isByNameRef(ftree)) tree.select(defn.Function0_apply).appliedToNone
+    if (isByNameRef(ftree))
+      ctx.atPhase(next) { implicit ctx => tree.select(defn.Function0_apply).appliedToNone }
     else tree
 
   override def transformIdent(tree: Ident)(implicit ctx: Context, info: TransformerInfo): Tree =
@@ -65,9 +66,11 @@ class ElimByName extends TransformByNameApply with InfoTransformer { thisTransfo
   }
 
   override def transformValDef(tree: ValDef)(implicit ctx: Context, info: TransformerInfo): Tree =
-    if (exprBecomesFunction(tree.symbol))
-      cpy.ValDef(tree)(tpt = tree.tpt.withType(tree.symbol.info))
-    else tree
+    ctx.atPhase(next) { implicit ctx =>
+      if (exprBecomesFunction(tree.symbol))
+        cpy.ValDef(tree)(tpt = tree.tpt.withType(tree.symbol.info))
+      else tree
+    }
 
   def transformInfo(tp: Type, sym: Symbol)(implicit ctx: Context): Type = tp match {
     case ExprType(rt) if exprBecomesFunction(sym) => defn.FunctionOf(Nil, rt)

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

@@ -25,7 +25,7 @@ import dotty.tools.dotc.core.Phases.Phase
 /** Make private term members that are accessed from another class
  *  non-private by resetting the Private flag and expanding their name.
  *
- *  Make private accessor in value class not-private. Ihis is necessary to unbox
+ *  Make private accessor in value class not-private. This is necessary to unbox
  *  the value class when accessing it from separate compilation units
  *
  *  Also, make non-private any private parameter forwarders that forward to an inherited

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

@@ -132,15 +132,11 @@ object ExplicitOuter {
   import ast.tpd._
 
   /** Ensure that class `cls` has outer accessors */
-  def ensureOuterAccessors(cls: ClassSymbol)(implicit ctx: Context): Unit = {
-    //todo: implementing  #165 would simplify this logic
-    val prevPhase = ctx.phase.prev
-    assert(prevPhase.id <= ctx.explicitOuterPhase.id, "can add $outer symbols only before ExplicitOuter")
-    assert(prevPhase.isInstanceOf[DenotTransformer], "adding outerAccessors requires being DenotTransformer")
-    if (!hasOuter(cls)) {
-      newOuterAccessors(cls).foreach(_.enteredAfter(prevPhase.asInstanceOf[DenotTransformer]))
+  def ensureOuterAccessors(cls: ClassSymbol)(implicit ctx: Context): Unit =
+    ctx.atPhase(ctx.explicitOuterPhase.next) { implicit ctx =>
+      if (!hasOuter(cls))
+        newOuterAccessors(cls).foreach(_.enteredAfter(ctx.explicitOuterPhase.asInstanceOf[DenotTransformer]))
     }
-  }
 
   /** The outer accessor and potentially outer param accessor needed for class `cls` */
   private def newOuterAccessors(cls: ClassSymbol)(implicit ctx: Context) =

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

@@ -131,7 +131,7 @@ class ExtensionMethods extends MiniPhaseTransform with DenotTransformer with Ful
   private def createExtensionMethod(imeth: Symbol, staticClass: Symbol)(implicit ctx: Context): TermSymbol = {
     val extensionName = extensionNames(imeth).head.toTermName
     val extensionMeth = ctx.newSymbol(staticClass, extensionName,
-      imeth.flags | Final &~ (Override | Protected | AbsOverride),
+      (imeth.flags | Final) &~ (Override | Protected | AbsOverride),
       fullyParameterizedType(imeth.info, imeth.owner.asClass),
       privateWithin = imeth.privateWithin, coord = imeth.coord)
     extensionMeth.addAnnotations(imeth.annotations)(ctx.withPhase(thisTransformer))
@@ -175,8 +175,8 @@ class ExtensionMethods extends MiniPhaseTransform with DenotTransformer with Ful
           extensionDefs(staticClass) = newC
           newC
       }
-      store += atGroupEnd(fullyParameterizedDef(extensionMeth, tree)(_))
-      cpy.DefDef(tree)(rhs = atGroupEnd(forwarder(extensionMeth, tree)(_)))
+      store += fullyParameterizedDef(extensionMeth, tree)
+      cpy.DefDef(tree)(rhs = forwarder(extensionMeth, tree))
     } else tree
   }
 }

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

@@ -64,8 +64,6 @@ class LambdaLift extends MiniPhase with IdentityDenotTransformer { thisTransform
   val phaseName: String = "lambdaLift"
   val treeTransform = new LambdaLifter
 
-  override def relaxedTyping = true
-
   override def runsAfterGroupsOf: Set[Class[_ <: Phase]] = Set(classOf[Constructors], classOf[HoistSuperArgs])
     // Constructors has to happen before LambdaLift because the lambda lift logic
     // becomes simpler if it can assume that parameter accessors have already been

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

@@ -166,12 +166,10 @@ class LazyVals extends MiniPhaseTransform with IdentityDenotTransformer {
     // backend requires field usage to be after field definition
     // need to bring containers to start of method
     val (holders, stats) =
-      atGroupEnd { implicit ctx: Context =>
-        trees.partition {
-          _.symbol.flags.&~(Flags.Touched) == containerFlags
-          // Filtering out Flags.Touched is not required currently, as there are no LazyTypes involved here
-          // but just to be more safe
-        }
+      trees.partition {
+        _.symbol.flags.&~(Flags.Touched) == containerFlags
+        // Filtering out Flags.Touched is not required currently, as there are no LazyTypes involved here
+        // but just to be more safe
       }
     holders:::stats
   }

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

@@ -6,7 +6,7 @@ import DenotTransformers.SymTransformer
 import Phases.Phase
 import Contexts.Context
 import SymDenotations.SymDenotation
-import TreeTransforms.MiniPhaseTransform
+import TreeTransforms.{MiniPhaseTransform, TransformerInfo}
 import Flags._, Symbols._
 
 /** 1. Widens all private[this] and protected[this] qualifiers to just private/protected

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

@@ -768,7 +768,7 @@ object PatternMatcher {
           def outerTest: Tree = trans.transformFollowingDeep {
             val expectedOuter = singleton(expectedTp.normalizedPrefix)
             val expectedClass = expectedTp.dealias.classSymbol.asClass
-            ExplicitOuter.ensureOuterAccessors(expectedClass)(ctx.withPhase(ctx.explicitOuterPhase.next))
+            ExplicitOuter.ensureOuterAccessors(expectedClass)
             scrutinee.ensureConforms(expectedTp)
               .outerSelect(1, expectedOuter.tpe.widen)
               .select(defn.Object_eq)

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

@@ -9,14 +9,15 @@ import dotty.tools.dotc.core.Names._
 import dotty.tools.dotc.core.Phases
 import dotty.tools.dotc.core.SymDenotations.SymDenotation
 import dotty.tools.dotc.core.Symbols._
-import dotty.tools.dotc.transform.TreeTransforms.MiniPhaseTransform
+import dotty.tools.dotc.transform.TreeTransforms.{MiniPhaseTransform, TransformerInfo}
 
 /** Renames lifted classes to local numbering scheme */
 class RenameLifted extends MiniPhaseTransform with SymTransformer { thisTransformer =>
 
   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])
 
   def transformSym(ref: SymDenotation)(implicit ctx: Context): SymDenotation =
     if (needsRefresh(ref.symbol)) ref.copySymDenotation(name = refreshedName(ref.symbol))