Add PolyFunctionOf (maybe not necessarry)

Author: zeptometer

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

@@ -383,4 +383,25 @@ object QuotesAndSplices {
         case _ =>
           super.transform(tree)
     end TreeMapWithVariance
+
+  // TODO-18271: Seems we can use PolyProto instead?
+  object PolyFunctionOf {
+    /**
+      * Return a poly-type + function type [$typeargs] => ($args) => ($resultType)
+      * where typeargs occur in args and resulttype
+      *
+      * @param typeargs
+      * @param args
+      * @param resultType
+      * @return
+      */
+    def apply(typeargs: List[Type], args: List[Type], resultType: Type)(using Context): Type =
+      val typeargs1 = PolyType.syntheticParamNames(typeargs.length)
+      // TODO-18271 What would be good bounds?
+      val paraminfosExp = (_: PolyType) => typeargs map (_ => TypeBounds.empty)
+      // TODO-18271 Replace type args occurence in args with typeargs1?
+      val resultTypeExp = (_: PolyType) => defn.FunctionOf(args, resultType)
+      val tpe = PolyType(typeargs1)(paraminfosExp, resultTypeExp)
+      RefinedType(defn.PolyFunctionType, nme.apply, tpe)
+  }
 }