Disentangle phases from treetransforms

TreeTransforms are no longer phases. This allows to generate
new transforms in prepare... methods without running into the
problem that thee new transforms are undefined as phases.

It also makes for a cleaner separation of concerns.

Author: odersky

src/dotty/tools/dotc/ElimLocals.scala

@@ -6,11 +6,11 @@ import DenotTransformers.SymTransformer
 import Phases.Phase
 import Contexts.Context
 import SymDenotations.SymDenotation
-import TreeTransforms.TreeTransform
+import TreeTransforms.MiniPhaseTransform
 import Flags.Local
 
 /** Widens all private[this] and protected[this] qualifiers to just private/protected */
-class ElimLocals extends TreeTransform with SymTransformer { thisTransformer =>
+class ElimLocals extends MiniPhaseTransform with SymTransformer { thisTransformer =>
   override def name = "elimlocals"
 
   def transformSym(ref: SymDenotation)(implicit ctx: Context) =

src/dotty/tools/dotc/core/Decorators.scala

@@ -130,7 +130,7 @@ object Decorators {
    */
   implicit class PhaseListDecorator(val names: List[String]) extends AnyVal {
     def containsPhase(phase: Phase): Boolean = phase  match {
-      case phase: TreeTransformer => phase.transformations.exists(containsPhase)
+      case phase: TreeTransformer => phase.transformations.exists(trans => containsPhase(trans.phase))
       case _ => names exists (n => n == "all" || phase.name.startsWith(n))
     }
   }

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

@@ -8,7 +8,7 @@ import DenotTransformers._
 import Denotations._
 import config.Printers._
 import scala.collection.mutable.{ListBuffer, ArrayBuffer}
-import dotty.tools.dotc.transform.TreeTransforms.{TreeTransformer, TreeTransform}
+import dotty.tools.dotc.transform.TreeTransforms.{TreeTransformer, MiniPhase, TreeTransform}
 import dotty.tools.dotc.transform.TreeTransforms
 import Periods._
 
@@ -80,7 +80,7 @@ object Phases {
           val phasesInBlock: Set[String] = phasess(i).map(_.name).toSet
           for(phase<-phasess(i)) {
             phase match {
-              case p: TreeTransform =>
+              case p: MiniPhase =>
 
                 val unmetRequirements = p.runsAfterGroupsOf &~ prevPhases
                 assert(unmetRequirements.isEmpty,
@@ -90,9 +90,9 @@ object Phases {
                 assert(false, s"Only tree transforms can be squashed, ${phase.name} can not be squashed")
             }
           }
-          val transforms = phasess(i).asInstanceOf[List[TreeTransform]]
+          val transforms = phasess(i).asInstanceOf[List[MiniPhase]].map(_.treeTransform)
           val block = new TreeTransformer {
-            override def name: String = transformations.map(_.name).mkString("TreeTransform:{", ", ", "}")
+            override def name: String = transformations.map(_.phase.name).mkString("TreeTransform:{", ", ", "}")
             override def transformations: Array[TreeTransform] = transforms.toArray
           }
           squashedPhases += block

src/dotty/tools/dotc/transform/CollectEntryPoints.scala

@@ -1,6 +1,6 @@
 package dotty.tools.dotc.transform
 
-import dotty.tools.dotc.transform.TreeTransforms.{TransformerInfo, TreeTransform, TreeTransformer}
+import dotty.tools.dotc.transform.TreeTransforms.{TransformerInfo, TreeTransform, TreeTransformer, MiniPhaseTransform}
 import dotty.tools.dotc.ast.tpd
 import dotty.tools.dotc.core.Contexts.Context
 import scala.collection.mutable.ListBuffer
@@ -23,7 +23,7 @@ import StdNames._
 import dotty.tools.dotc.util.Positions.Position
 import dotty.tools.dotc.config.JavaPlatform
 
-class CollectEntryPoints extends TreeTransform {
+class CollectEntryPoints extends MiniPhaseTransform {
 
   /** perform context-dependant initialization */
   override def init(implicit ctx: Context, info: TransformerInfo): Unit = {

src/dotty/tools/dotc/transform/Constructors.scala

@@ -9,7 +9,7 @@ import dotty.tools.dotc.core.StdNames._
  *  Right now it's a dummy.
  *  Awaiting for real implemetation
  */
-class Constructors extends TreeTransform {
+class Constructors extends MiniPhaseTransform {
 
   override def name: String = "constructors"
   override def transformDefDef(tree: DefDef)(implicit ctx: Context, info: TransformerInfo): Tree = {

src/dotty/tools/dotc/transform/ElimRepeated.scala

@@ -4,7 +4,7 @@ package transform
 import core._
 import Names._
 import Types._
-import TreeTransforms.{TransformerInfo, TreeTransform, TreeTransformer}
+import TreeTransforms.{TransformerInfo, MiniPhaseTransform, TreeTransformer}
 import ast.Trees.flatten
 import Flags._
 import Contexts.Context
@@ -20,7 +20,7 @@ import TypeUtils._
 /** A transformer that removes repeated parameters (T*) from all types, replacing
  *  them with Seq types.
  */
-class ElimRepeated extends TreeTransform with InfoTransformer { thisTransformer =>
+class ElimRepeated extends MiniPhaseTransform with InfoTransformer { thisTransformer =>
   import ast.tpd._
 
   override def name = "elimrepeated"

src/dotty/tools/dotc/transform/FirstTransform.scala

@@ -3,7 +3,7 @@ package transform
 
 import core._
 import Names._
-import TreeTransforms.{TransformerInfo, TreeTransform, TreeTransformer}
+import TreeTransforms.{TransformerInfo, MiniPhaseTransform, TreeTransformer}
 import ast.Trees._
 import Flags._
 import Types._
@@ -23,7 +23,7 @@ import NameOps._
  *   - checks the bounds of AppliedTypeTrees
  *   - stubs out native methods
  */
-class FirstTransform extends TreeTransform with IdentityDenotTransformer { thisTransformer =>
+class FirstTransform extends MiniPhaseTransform with IdentityDenotTransformer { thisTransformer =>
   import ast.tpd._
 
   override def name = "companions"

src/dotty/tools/dotc/transform/InterceptedMethods.scala

@@ -40,7 +40,7 @@ import StdNames._
   *     using the most precise overload available
   * - `x.getClass` for getClass in primitives becomes `x.getClass` with getClass in class Object.
   */
-class InterceptedMethods extends TreeTransform {
+class InterceptedMethods extends MiniPhaseTransform {
 
   import tpd._
 

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

@@ -8,7 +8,7 @@ import Symbols._
 import Decorators._
 import NameOps._
 import StdNames.nme
-import dotty.tools.dotc.transform.TreeTransforms.{TransformerInfo, TreeTransformer, TreeTransform}
+import dotty.tools.dotc.transform.TreeTransforms.{TransformerInfo, TreeTransformer, MiniPhaseTransform}
 import dotty.tools.dotc.ast.Trees._
 import dotty.tools.dotc.ast.{untpd, tpd}
 import dotty.tools.dotc.core.Constants.Constant
@@ -43,7 +43,7 @@ class LazyValTranformContext {
     }
   }
 
-  class LazyValsTransform extends TreeTransform with DenotTransformer {
+  class LazyValsTransform extends MiniPhaseTransform with DenotTransformer {
 
     override def name: String = "LazyVals"
 

src/dotty/tools/dotc/transform/Literalize.scala

@@ -15,7 +15,7 @@ import ast.Trees._
  *  The constant types are eliminated by erasure, so we need to keep
  *  the info about constantness in the trees.
  */
-class Literalize extends TreeTransform {
+class Literalize extends MiniPhaseTransform {
   import ast.tpd._
 
   override def name: String = "literalize"

src/dotty/tools/dotc/transform/Nullarify.scala

@@ -34,7 +34,7 @@ import ast.Trees._
  *      expr        ==>    () => expr  if other expr is an argument to a call-by-name parameter
  *
  */
-class Nullarify extends TreeTransform with InfoTransformer {
+class Nullarify extends MiniPhaseTransform with InfoTransformer {
   import ast.tpd._
 
   override def name: String = "nullarify"

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

@@ -16,7 +16,7 @@ import ast.Trees._
 /** This transform eliminates patterns. Right now it's a dummy.
  *  Awaiting the real pattern matcher.
  */
-class PatternMatcher extends TreeTransform {
+class PatternMatcher extends MiniPhaseTransform {
   import ast.tpd._
 
   override def name: String = "patternMatcher"

src/dotty/tools/dotc/transform/Splitter.scala

@@ -12,7 +12,7 @@ import Contexts._, Types._, Decorators._, Denotations._, Symbols._, SymDenotatio
  *
  *  For now, only self references are treated.
  */
-class Splitter extends TreeTransform {
+class Splitter extends MiniPhaseTransform {
   import ast.tpd._
 
   override def name: String = "splitter"

src/dotty/tools/dotc/transform/TailRec.scala

@@ -10,7 +10,7 @@ import dotty.tools.dotc.core.Symbols._
 import dotty.tools.dotc.core.Types._
 import dotty.tools.dotc.core._
 import dotty.tools.dotc.transform.TailRec._
-import dotty.tools.dotc.transform.TreeTransforms.{TransformerInfo, TreeTransform}
+import dotty.tools.dotc.transform.TreeTransforms.{TransformerInfo, MiniPhaseTransform}
 
 /**
  * A Tail Rec Transformer
@@ -62,7 +62,7 @@ import dotty.tools.dotc.transform.TreeTransforms.{TransformerInfo, TreeTransform
  *             self recursive functions, that's why it's renamed to tailrec
  *             </p>
  */
-class TailRec extends TreeTransform with DenotTransformer with FullParameterization {
+class TailRec extends MiniPhaseTransform with DenotTransformer with FullParameterization {
 
   import dotty.tools.dotc.ast.tpd._