Fix a typo that caused unnecessary cache invalidation

This uncovered a missing case for changeParents

Author: smarter

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

@@ -360,7 +360,7 @@ object Phases {
       myRefChecked   = prev.getClass == classOf[RefChecks]    || prev.refChecked
       myLabelsReordered = prev.getClass == classOf[LabelDefs] || prev.labelsReordered
       mySameMembersStartId = if (changesMembers) id else prev.sameMembersStartId
-      mySameParentsStartId = if (changesParents) id else prev.sameMembersStartId
+      mySameParentsStartId = if (changesParents) id else prev.sameParentsStartId
     }
 
     protected[Phases] def init(base: ContextBase, id: Int): Unit = init(base, id, id)

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

@@ -45,6 +45,8 @@ class ElimByName extends TransformByNameApply with InfoTransformer {
   override def runsAfterGroupsOf = Set(Splitter.name)
     // I got errors running this phase in an earlier group, but I did not track them down.
 
+  override def changesParents: Boolean = true // Only true for by-names
+
   /** 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))
@@ -82,4 +84,4 @@ class ElimByName extends TransformByNameApply with InfoTransformer {
 
 object ElimByName {
   val name = "elimByName"
-}
+}