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, 5 insertions, 9 deletions

diff --git a/src/dotty/tools/dotc/core/Periods.scala b/src/dotty/tools/dotc/core/Periods.scala
index 592516531..1c9fbf0c6 100644
--- a/src/dotty/tools/dotc/core/Periods.scala
+++ b/src/dotty/tools/dotc/core/Periods.scala
@@ -27,20 +27,16 @@ abstract class Periods extends DotClass { self: Context =>
 
   /** The period containing the current period where denotations do not change.
    *  We compute this by taking as first phase the first phase less or equal to
-   *  the current phase that has the same "nextTransformer". As last phase
-   *  we take the phaseId of the nextTransformer - 1. This has the advantage that
-   *  it works even if no transformer is installed other than the sentinel
-   *  NoTransformer, which is always installed automatically.
+   *  the current phase that has the same "nextTransformerId". As last phase
+   *  we take the next transformer id following the current phase.
    */
   def stablePeriod = {
     var first = phaseId
-    val transformers = base.denotTransformers
-    val nxTrans = transformers.nextTransformer(first)
-    while (first - 1 > NoPhaseId &&
-           (transformers.nextTransformer(first - 1) eq nxTrans)) {
+    val nxTrans = ctx.base.nextTransformerId(first)
+    while (first - 1 > NoPhaseId && (ctx.base.nextTransformerId(first - 1) == nxTrans)) {
       first -= 1
     }
-    Period(runId, first, nxTrans.phaseId - 1)
+    Period(runId, first, nxTrans)
   }
 }