InfoTransformers as specific DenotTransformers

Factored out denot transformer behavior where the we transform types
in a uniform way into InfoTransformers.

Author: odersky

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

@@ -5,6 +5,7 @@ import Periods._
 import SymDenotations._
 import Contexts._
 import Types._
+import Symbols._
 import Denotations._
 import Phases._
 import java.lang.AssertionError
@@ -30,4 +31,19 @@ object DenotTransformers {
     /** The transformation method */
     def transform(ref: SingleDenotation)(implicit ctx: Context): SingleDenotation
   }
+
+  trait InfoTransformer extends DenotTransformer {
+
+    def transformInfo(tp: Type, sym: Symbol)(implicit ctx: Context): Type
+
+    /** The transformation method */
+    def transform(ref: SingleDenotation)(implicit ctx: Context): SingleDenotation = {
+      val info1 = transformInfo(ref.info, ref.symbol)
+      if (info1 eq ref.info) ref
+      else ref match {
+        case ref: SymDenotation => ref.copySymDenotation(info = info1)
+        case _ => ref.derivedSingleDenotation(ref.symbol, info1)
+      }
+    }
+  }
 }

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

@@ -2,7 +2,6 @@ package dotty.tools.dotc
 package transform
 
 import TreeTransforms._
-import core.DenotTransformers._
 import core.Denotations._
 import core.SymDenotations._
 import core.Contexts._
@@ -27,7 +26,6 @@ import dotty.runtime.LazyVals
 import scala.collection.mutable.ListBuffer
 import dotty.tools.dotc.core.Denotations.SingleDenotation
 import dotty.tools.dotc.core.SymDenotations.SymDenotation
-import dotty.tools.dotc.core.DenotTransformers.DenotTransformer
 import StdNames._
 
 /** Replace member references as follows:

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

@@ -2,7 +2,6 @@ package dotty.tools.dotc
 package transform
 
 import TreeTransforms._
-import core.DenotTransformers._
 import core.Denotations._
 import core.SymDenotations._
 import core.Contexts._

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

@@ -2,7 +2,6 @@ package dotty.tools.dotc
 package transform
 
 import TreeTransforms._
-import core.DenotTransformers._
 import core.Denotations._
 import core.SymDenotations._
 import core.Contexts._

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

@@ -7,10 +7,11 @@ import core.Denotations._
 import core.SymDenotations._
 import core.Contexts._
 import core.Types._
+import core.Symbols._
 import ast.Trees._
 import ast.tpd.{Apply, Tree, cpy}
 
-class UncurryTreeTransform extends TreeTransform with DenotTransformer {
+class UncurryTreeTransform extends TreeTransform with InfoTransformer {
 
   override def name: String = "uncurry"
   override def transformApply(tree: Apply)(implicit ctx: Context, info: TransformerInfo): Tree =
@@ -40,12 +41,6 @@ class UncurryTreeTransform extends TreeTransform with DenotTransformer {
       tp
   }
 
-  def transform(ref: SingleDenotation)(implicit ctx: Context): SingleDenotation = {
-    val info1 = uncurry(ref.info)
-    if (info1 eq ref.info) ref
-    else ref match {
-      case ref: SymDenotation => ref.copySymDenotation(info = info1)
-      case _ => ref.derivedSingleDenotation(ref.symbol, info1)
-    }
-  }
+  def transformInfo(tp: Type, sym: Symbol)(implicit ctx: Context): Type =
+    uncurry(tp)
 }