Simplification: drop ccNestingLevel

Author: odersky

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

@@ -57,9 +57,6 @@ class CCState:
   /** Cache for level ownership */
   val isLevelOwner: mutable.HashMap[Symbol, Boolean] = new mutable.HashMap
 
-  /** Associates certain symbols (the nesting level owners) with their ccNestingLevel */
-  val nestingLevels: mutable.HashMap[Symbol, Int] = new mutable.HashMap
-
   /** Associates nesting level owners with the local roots valid in their scopes. */
   val localRoots: mutable.HashMap[Symbol, Symbol] = new mutable.HashMap
 
@@ -451,24 +448,6 @@ extension (sym: Symbol)
     recur(sym, NoSymbol)
       .showing(i"find outer $sym [ $name ] = $result", capt)
 
-  /** The nesting level of `sym` for the purposes of `cc`,
-   *  -1 for NoSymbol
-   */
-  def ccNestingLevel(using Context): Int =
-    if sym.exists then
-      val lowner = sym.levelOwner
-      ccState.nestingLevels.getOrElseUpdate(lowner,
-        if lowner.isRoot then 0 else lowner.owner.ccNestingLevel + 1)
-    else -1
-
-  /** Optionally, the nesting level of `sym` for the purposes of `cc`, provided
-   *  a capture checker is running.
-   */
-  def ccNestingLevelOpt(using Context): Option[Int] =
-    if ctx.phase == Phases.checkCapturesPhase || ctx.phase == Phases.checkCapturesPhase.prev
-    then Some(ccNestingLevel)
-    else None
-
   /** The parameter with type caps.Cap in the leading term parameter section,
    *  or NoSymbol, if none exists.
    */
@@ -482,7 +461,7 @@ extension (sym: Symbol)
     val owner = sym.levelOwner
     assert(owner.exists)
     def newRoot = newSymbol(if owner.isClass then newLocalDummy(owner) else owner,
-      nme.LOCAL_CAPTURE_ROOT, Synthetic, defn.Caps_Cap.typeRef, nestingLevel = owner.ccNestingLevel)
+      nme.LOCAL_CAPTURE_ROOT, Synthetic, defn.Caps_Cap.typeRef)
     def lclRoot =
       if owner.isTerm then owner.definedLocalRoot.orElse(newRoot)
       else newRoot
@@ -500,12 +479,6 @@ extension (sym: Symbol)
     else if !sym.exists || sym.isContainedIn(other) then other
     else sym.owner.minNested(other.owner)
 
-extension (tp: TermRef | ThisType)
-  /** The nesting level of this reference as defined by capture checking */
-  def ccNestingLevel(using Context): Int = tp match
-    case tp: TermRef => tp.symbol.ccNestingLevel
-    case tp: ThisType => tp.cls.ccNestingLevel
-
 extension (tp: AnnotatedType)
   /** Is this a boxed capturing type? */
   def isBoxed(using Context): Boolean = tp.annot match

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

@@ -36,7 +36,7 @@ import config.Printers.{core, typr, matchTypes}
 import reporting.{trace, Message}
 import java.lang.ref.WeakReference
 import compiletime.uninitialized
-import cc.{CapturingType, CaptureSet, derivedCapturingType, isBoxedCapturing, RetainingType, ccNestingLevel, CaptureRoot}
+import cc.{CapturingType, CaptureSet, derivedCapturingType, isBoxedCapturing, RetainingType, CaptureRoot}
 import CaptureSet.{CompareResult, IdempotentCaptRefMap, IdentityCaptRefMap}
 
 import scala.annotation.internal.sharable

compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala

@@ -15,7 +15,7 @@ import util.SourcePosition
 import scala.util.control.NonFatal
 import scala.annotation.switch
 import config.{Config, Feature}
-import cc.{CapturingType, RetainingType, CaptureSet, CaptureRoot, isBoxed, ccNestingLevel, levelOwner, retainedElems}
+import cc.{CapturingType, RetainingType, CaptureSet, CaptureRoot, isBoxed, levelOwner, retainedElems}
 
 class PlainPrinter(_ctx: Context) extends Printer {
 
@@ -374,10 +374,7 @@ class PlainPrinter(_ctx: Context) extends Printer {
    */
   protected def idString(sym: Symbol): String =
     (if (showUniqueIds || Printer.debugPrintUnique) "#" + sym.id else "") +
-    (if showNestingLevel then
-      if ctx.phase == Phases.checkCapturesPhase then "%" + sym.ccNestingLevel
-      else "%" + sym.nestingLevel
-     else "")
+    (if showNestingLevel then "%" + sym.nestingLevel else "")
 
   def nameString(sym: Symbol): String =
     simpleNameString(sym) + idString(sym) // + "<" + (if (sym.exists) sym.owner else "") + ">"
@@ -408,11 +405,9 @@ class PlainPrinter(_ctx: Context) extends Printer {
     tp match {
       case tp: TermRef =>
         if tp.symbol.name == nme.LOCAL_CAPTURE_ROOT then  // TODO: Move to toTextCaptureRef
-          if ctx.owner.levelOwner == tp.localRootOwner && !printDebug && shortenCap then
-            Str("cap")
-          else
-            Str(s"cap[${tp.localRootOwner.name}]") ~
-              Str(s"%${tp.symbol.ccNestingLevel}").provided(showNestingLevel)
+          if ctx.owner.levelOwner == tp.localRootOwner && !printDebug && shortenCap
+          then Str("cap")
+          else Str(s"cap[${tp.localRootOwner.name}]")
         else toTextPrefixOf(tp) ~ selectionString(tp)
       case tp: ThisType =>
         nameString(tp.cls) + ".this"
@@ -436,9 +431,7 @@ class PlainPrinter(_ctx: Context) extends Printer {
         if tp.followAlias ne tp then toTextRef(tp.followAlias)
         else
           def boundText(sym: Symbol): Text =
-            (toTextRef(sym.termRef)
-              ~ Str(s"/${sym.ccNestingLevel}").provided(showNestingLevel)
-            ).provided(sym.exists)
+            toTextRef(sym.termRef).provided(sym.exists)
           "'cap["
           ~ toTextRef(tp.outerLimit.termRef).provided(!tp.outerLimit.isRoot)
           ~ ".."

compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala

@@ -29,7 +29,7 @@ import config.{Config, Feature}
 
 import dotty.tools.dotc.util.SourcePosition
 import dotty.tools.dotc.ast.untpd.{MemberDef, Modifiers, PackageDef, RefTree, Template, TypeDef, ValOrDefDef}
-import cc.{CaptureSet, CapturingType, toCaptureSet, IllegalCaptureRef, ccNestingLevelOpt}
+import cc.{CaptureSet, CapturingType, toCaptureSet, IllegalCaptureRef}
 
 class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
 
@@ -868,13 +868,10 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
 
   protected def optAscription[T <: Untyped](tpt: Tree[T]): Text = optText(tpt)(": " ~ _)
 
-  private def nestingLevel(sym: Symbol): Int =
-    sym.ccNestingLevelOpt.getOrElse(sym.nestingLevel)
-
   private def idText(tree: untpd.Tree): Text =
     (if showUniqueIds && tree.hasType && tree.symbol.exists then s"#${tree.symbol.id}" else "") ~
     (if showNestingLevel then tree.typeOpt match
-      case tp: NamedType if !tp.symbol.isStatic => s"%${nestingLevel(tp.symbol)}"
+      case tp: NamedType if !tp.symbol.isStatic => s"%${tp.symbol.nestingLevel}"
       case tp: TypeVar => s"%${tp.nestingLevel}"
       case tp: TypeParamRef => ctx.typerState.constraint.typeVarOfParam(tp) match
         case tvar: TypeVar => s"%${tvar.nestingLevel}"