Fix caching of baseData in SymDenotations

Without the setting, the outdated baseData cache will be used which produces incorrect baseClasses

Author: liufengyun

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

@@ -76,6 +76,13 @@ class PostTyper extends MacroTransform with InfoTransformer { thisPhase =>
 
   override def changesMembers: Boolean = true // the phase adds super accessors and synthetic members
 
+  /**
+   * Serializable and AbstractFunction are added for scala2-library companion object of case class
+   *
+   * Ideally `compilingScala2StdLib` should be used, but it is initialized too late to be effective.
+   */
+  override def changesParents: Boolean = true
+
   override def transformPhase(using Context): Phase = thisPhase.next
 
   def newTransformer(using Context): Transformer =

compiler/src/dotty/tools/dotc/transform/init/Checker.scala

@@ -36,12 +36,16 @@ class Checker extends Phase:
     traverser.traverse(unit.tpdTree)
 
   override def runOn(units: List[CompilationUnit])(using Context): List[CompilationUnit] =
-    val checkCtx = ctx.fresh.setPhase(this.start)
+    val checkCtx = ctx.fresh.setPhase(this)
     val traverser = new InitTreeTraverser()
-    val unitContexts = units.map(unit => checkCtx.fresh.setCompilationUnit(unit))
 
     val units0 =
-      for unitContext <- unitContexts if traverse(traverser)(using unitContext) yield unitContext.compilationUnit
+      for
+        unit <- units
+        unitContext = checkCtx.fresh.setCompilationUnit(unit)
+        if traverse(traverser)(using unitContext)
+      yield
+        unitContext.compilationUnit
 
     cancellable {
       val classes = traverser.getClasses()

compiler/src/dotty/tools/dotc/transform/init/Objects.scala

@@ -11,6 +11,7 @@ import StdNames.*
 import Names.TermName
 import NameKinds.OuterSelectName
 import NameKinds.SuperAccessorName
+import Decorators.*
 
 import ast.tpd.*
 import util.{ SourcePosition, NoSourcePosition }
@@ -66,12 +67,11 @@ import dotty.tools.dotc.core.Flags.AbstractOrTrait
  *     whole-program analysis. However, the check is not modular in terms of project boundaries.
  *
  */
-import Decorators.*
 class Objects(using Context @constructorOnly):
   val immutableHashSetBuider: Symbol = requiredClass("scala.collection.immutable.HashSetBuilder")
   // TODO: this should really be an annotation on the rhs of the field initializer rather than the field itself.
   val HashSetBuilder_rootNode: Symbol = immutableHashSetBuider.requiredValue("rootNode")
-  
+
   val whiteList = Set(HashSetBuilder_rootNode)
 
   // ----------------------------- abstract domain -----------------------------