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

@@ -74,7 +74,13 @@ extension (using qctx: Quotes)(ann: qctx.reflect.Symbol)
 end extension
 
 extension (using qctx: Quotes)(tpe: qctx.reflect.TypeRepr) // FIXME clean up and have versions on Symbol for those
-  def isCaptureRoot: Boolean = tpe.termSymbol == CaptureDefs.captureRoot
+  def isCaptureRoot: Boolean =
+    import qctx.reflect.*
+    tpe match
+      case TermRef(ThisType(TypeRef(NoPrefix(), "caps")), "cap") => true
+      case TermRef(TermRef(ThisType(TypeRef(NoPrefix(), "scala")), "caps"), "cap") => true
+      case TermRef(TermRef(TermRef(TermRef(NoPrefix(), "_root_"), "scala"), "caps"), "cap") => true
+      case _ => false
 
   // NOTE: There's something horribly broken with Symbols, and we can't rely on tests like .isContextFunctionType either,
   // so we do these lame string comparisons instead.
@@ -182,4 +188,4 @@ 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