Refactored denotation transformers

Many small and large changes. Added samplePhase to demonstrate functionality.

To test functioning, run the compiler with args

     tests/pos/uncurry.scala -Ylog:sample,terminal

1 files changed, 4 insertions, 40 deletions

diff --git a/src/dotty/tools/dotc/core/DenotTransformers.scala b/src/dotty/tools/dotc/core/DenotTransformers.scala
index f41f1d171..be85b5877 100644
--- a/src/dotty/tools/dotc/core/DenotTransformers.scala
+++ b/src/dotty/tools/dotc/core/DenotTransformers.scala
@@ -6,62 +6,26 @@ import SymDenotations._
 import Contexts._
 import Types._
 import Denotations._
+import Phases._
 import java.lang.AssertionError
 import dotty.tools.dotc.util.DotClass
 
 object DenotTransformers {
 
-  trait DenotTransformerBase { self: ContextBase =>
-    val denotTransformers = new DenotTransformerGroup
-  }
-
   /** A transformer group contains a sequence of transformers,
    *  ordered by the phase where they apply. Transformers are added
    *  to a group via `install`.
-   *
-   *  There are two transformerGroups in a context base:
-   *  symTransformers and refTransformers. symTransformers translate
-   *  full symbol denotations, refTransformers translate only symbol references
-   *  of type Unique/JointRefDenotation.
    */
-  class DenotTransformerGroup {
-
-    private val nxTransformer =
-      Array.fill[DenotTransformer](MaxPossiblePhaseId + 1)(NoTransformer)
-
-    def nextTransformer(pid: PhaseId) = nxTransformer(pid)
-
-    def install(pid: PhaseId, transFn: DenotTransformerGroup => DenotTransformer): Unit =
-      if ((pid > NoPhaseId) && (nxTransformer(pid).phaseId > pid)) {
-        val trans = transFn(this)
-        trans._phaseId = pid
-        nxTransformer(pid) = transFn(this)
-        install(pid - 1, transFn)
-      }
-
-    /** A sentinel transformer object */
-    object NoTransformer extends DenotTransformer(this) {
-      _phaseId = MaxPossiblePhaseId + 1
-      override def lastPhaseId = phaseId - 1 // TODO JZ Probably off-by-N error here. MO: Don't think so: we want empty validity period.
-      def transform(ref: SingleDenotation)(implicit ctx: Context): SingleDenotation =
-        unsupported("transform")
-    }
-  }
 
   /** A transformer transforms denotations at a given phase */
-  abstract class DenotTransformer(group: DenotTransformerGroup) extends DotClass {
-
-    private[DenotTransformers] var _phaseId: PhaseId = _
-
-    /** The phase at the start of which the denotations are transformed */
-    def phaseId: PhaseId = _phaseId
+  trait DenotTransformer extends Phase {
 
     /** The last phase during which the transformed denotations are valid */
-    def lastPhaseId = group.nextTransformer(phaseId).phaseId - 1
+    def lastPhaseId(implicit ctx: Context) = ctx.nextTransformerId(id + 1)
 
     /** The validity period of the transformer in the given context */
     def validFor(implicit ctx: Context): Period =
-      Period(ctx.runId, phaseId, lastPhaseId)
+      Period(ctx.runId, id, lastPhaseId)
 
     /** The transformation method */
     def transform(ref: SingleDenotation)(implicit ctx: Context): SingleDenotation