Make isCapSetCap reject cap* and cap.rd

Author: natsukagami

local/project/dummy/capturevars.scala

@@ -25,3 +25,6 @@ trait Test:
     def baz2(x: U[{caps.cap}]): Unit
     def test[E^, F^ >: {caps.cap} <: {}, G <: [C^ >: {a,b} <: {a,b}] =>> AnyRef^{C}](x: T[{E,a,b}], y: U[F]): Unit
     val poly: [C^ >: {a,b}] => (f: () ->{C} Unit) -> Int ->{C} Unit
+
+    def readup[T^ <: {cap.rd}]() = ()
+    def readlo[T^ >: {cap.rd}]() = ()

scaladoc/src/dotty/tools/scaladoc/cc/CaptureOps.scala

@@ -103,7 +103,11 @@ extension (using qctx: Quotes)(tpe: qctx.reflect.TypeRepr) // FIXME clean up and
 
   def isCapSetCap: Boolean =
     tpe.isCapSet && tpe.match
-      case CapturingType(_, List(ref)) => ref.isCaptureRoot
+      case CapturingType(_, List(ref)) =>
+        ref.isCaptureRoot && (ref match // make sure it's not cap* or cap.rd
+          case ReachCapability(_) => false
+          case ReadOnlyCapability(_) => false
+          case _ => true)
       case _ => false
 end extension
 
@@ -182,4 +186,4 @@ object CapturingType:
       case AnnotatedType(base, Apply(Select(New(annot), _), Nil)) if annot.symbol == CaptureDefs.retainsCap =>
         Some((base, List(CaptureDefs.captureRoot.termRef)))
       case _ => None
-end CapturingType
+end CapturingType