Record level of current owner when creating Fresh instances

Author: odersky

compiler/src/dotty/tools/dotc/cc/CaptureSet.scala

@@ -423,8 +423,8 @@ object CaptureSet:
   def universalImpliedByCapability(using Context) =
     defn.universalCSImpliedByCapability
 
-  def fresh(owner: Symbol = NoSymbol)(using Context): CaptureSet =
-    root.Fresh.withOwner(owner).singletonCaptureSet
+  def fresh()(using Context): CaptureSet =
+    root.Fresh().singletonCaptureSet
 
   /** The shared capture set `{cap.rd}` */
   def shared(using Context): CaptureSet =
@@ -689,7 +689,7 @@ object CaptureSet:
     def solve()(using Context): Unit =
       CCState.withCapAsRoot: // // OK here since we infer parameter types that get checked later
         val approx = upperApprox(empty)
-          .map(root.CapToFresh(NoSymbol).inverse)    // Fresh --> cap
+          .map(root.CapToFresh().inverse)    // Fresh --> cap
           .showing(i"solve $this = $result", capt)
         //println(i"solving var $this $approx ${approx.isConst} deps = ${deps.toList}")
         val newElems = approx.elems -- elems
@@ -1392,7 +1392,7 @@ object CaptureSet:
       def capturingCase(acc: CaptureSet, parent: Type, refs: CaptureSet) =
         this(acc, parent) ++ refs
       def abstractTypeCase(acc: CaptureSet, t: TypeRef, upperBound: Type) =
-        if includeTypevars && upperBound.isExactlyAny then CaptureSet.fresh(t.symbol)
+        if includeTypevars && upperBound.isExactlyAny then CaptureSet.fresh()
         else this(acc, upperBound)
     collect(CaptureSet.empty, tp)
 

compiler/src/dotty/tools/dotc/cc/CheckCaptures.scala

@@ -825,7 +825,7 @@ class CheckCaptures extends Recheck, SymTransformer:
         var refined: Type = core
         var allCaptures: CaptureSet =
           if core.derivesFromMutable then initCs ++ CaptureSet.fresh()
-          else if core.derivesFromCapability then initCs ++ root.Fresh.withOwner(core.classSymbol).readOnly.singletonCaptureSet
+          else if core.derivesFromCapability then initCs ++ root.Fresh().readOnly.singletonCaptureSet
           else initCs
         for (getterName, argType) <- mt.paramNames.lazyZip(argTypes) do
           val getter = cls.info.member(getterName).suchThat(_.isRefiningParamAccessor).symbol

compiler/src/dotty/tools/dotc/cc/root.scala

@@ -125,9 +125,9 @@ object root:
   /** The type of fresh references */
   type Fresh = AnnotatedType
 
+  /** Constructor and extractor methods for "fresh" capabilities */
   object Fresh:
-    /** Constructor and extractor methods for "fresh" capabilities */
-    private def make(owner: Symbol)(using Context): CaptureRef =
+    def apply(using Context)(owner: Symbol = ctx.owner): CaptureRef =
       if ccConfig.useSepChecks then
         val hiddenSet = CaptureSet.HiddenSet(owner)
         val res = AnnotatedType(cap, Annot(Kind.Fresh(hiddenSet)))
@@ -137,9 +137,6 @@ object root:
       else
         cap
 
-    def withOwner(owner: Symbol)(using Context): CaptureRef = make(owner)
-    def apply()(using Context): CaptureRef = make(NoSymbol)
-
     def unapply(tp: AnnotatedType): Option[CaptureSet.HiddenSet] = tp.annot match
       case Annot(Kind.Fresh(hidden)) => Some(hidden)
       case _ => None
@@ -168,14 +165,14 @@ object root:
   /** Map each occurrence of cap to a different Fresh instance
    *  Exception: CapSet^ stays as it is.
    */
-  class CapToFresh(owner: Symbol)(using Context) extends BiTypeMap, FollowAliasesMap:
+  class CapToFresh()(using Context) extends BiTypeMap, FollowAliasesMap:
     thisMap =>
 
     override def apply(t: Type) =
       if variance <= 0 then t
       else t match
         case t: CaptureRef if t.isCap =>
-          Fresh.withOwner(owner)
+          Fresh()
         case t @ CapturingType(parent: TypeRef, _) if parent.symbol == defn.Caps_CapSet =>
           t
         case t @ CapturingType(_, _) =>
@@ -213,12 +210,12 @@ object root:
   end CapToFresh
 
   /** Maps cap to fresh */
-  def capToFresh(tp: Type, owner: Symbol = NoSymbol)(using Context): Type =
-    if ccConfig.useSepChecks then CapToFresh(owner)(tp) else tp
+  def capToFresh(tp: Type)(using Context): Type =
+    if ccConfig.useSepChecks then CapToFresh()(tp) else tp
 
   /** Maps fresh to cap */
   def freshToCap(tp: Type)(using Context): Type =
-    if ccConfig.useSepChecks then CapToFresh(NoSymbol).inverse(tp) else tp
+    if ccConfig.useSepChecks then CapToFresh().inverse(tp) else tp
 
   /** Map top-level free existential variables one-to-one to Fresh instances */
   def resultToFresh(tp: Type)(using Context): Type =