Optimize boxedUnlessFun

Author: odersky

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

@@ -68,7 +68,7 @@ extension (tp: Type)
         //.showing(i"boxedUF $tp in $tycon = $result")
 
   /** The boxed capture set of a type */
-  def boxedCaptured(using Context): CaptureSet =
+  def boxedCaptureSet(using Context): CaptureSet =
     def getBoxed(tp: Type): CaptureSet = tp match
       case tp @ CapturingType(parent, refs) =>
         val pcs = getBoxed(parent)
@@ -80,7 +80,7 @@ extension (tp: Type)
       case _ => CaptureSet.empty
     getBoxed(tp)
 
-  def isBoxedCapturing(using Context) = !tp.boxedCaptured.isAlwaysEmpty
+  def isBoxedCapturing(using Context) = !tp.boxedCaptureSet.isAlwaysEmpty
 
   def stripCapturing(using Context): Type = tp.dealiasKeepAnnots match
     case CapturingType(parent, _) =>
@@ -133,3 +133,9 @@ extension (tp: AnnotatedType)
     case ann: CaptureAnnotation => ann.boxed
     case _ => false
 
+extension (ts: List[Type])
+  def boxedUnlessFun(tycon: Type)(using Context) =
+    if ctx.phase != Phases.checkCapturesPhase || defn.isFunctionClass(tycon.typeSymbol)
+    then ts
+    else ts.mapconserve(_.boxed)
+

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

@@ -494,10 +494,9 @@ class TypeApplications(val self: Type) extends AnyVal {
    *  otherwise return Nil.
    *  Existential types in arguments are returned as TypeBounds instances.
    */
-  final def argInfos(using Context): List[Type] = self.stripped match {
-    case AppliedType(tycon, args) => args.mapconserve(_.boxedUnlessFun(tycon))
+  final def argInfos(using Context): List[Type] = self.stripped match
+    case AppliedType(tycon, args) => args.boxedUnlessFun(tycon)
     case _ => Nil
-  }
 
   /** Argument types where existential types in arguments are disallowed */
   def argTypes(using Context): List[Type] = argInfos mapConserve noBounds

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

@@ -187,7 +187,7 @@ class CheckCaptures extends Recheck, SymTransformer:
           includeIn(curEnv.outer)
 
     def includeBoxedCaptures(tp: Type, pos: SrcPos)(using Context): Unit =
-      includeBoxedCaptures(tp.boxedCaptured, pos)
+      includeBoxedCaptures(tp.boxedCaptureSet, pos)
 
     def includeBoxedCaptures(refs: CaptureSet, pos: SrcPos)(using Context): Unit =
       if curEnv.isOpen then
@@ -213,9 +213,9 @@ class CheckCaptures extends Recheck, SymTransformer:
      */
     def addResultBoxes(tp: Type)(using Context): Type =
       def includeBoxed(res: Type) =
-        //if !res.boxedCaptured.isAlwaysEmpty then
-        //  println(i"add boxed $tp from ${res.boxedCaptured}")
-        tp.capturing(res.boxedCaptured)
+        //if !res.boxedCaptureSet.isAlwaysEmpty then
+        //  println(i"add boxed $tp from ${res.boxedCaptureSet}")
+        tp.capturing(res.boxedCaptureSet)
       val tp1 = tp.dealias
       val boxedTp = tp1 match
         case tp1 @ AppliedType(_, args) if defn.isNonRefinedFunction(tp1) =>