Use isRefinedFunctionType in place of poly || erased

Author: natsukagami

compiler/src/dotty/tools/dotc/ast/TreeInfo.scala

@@ -960,9 +960,7 @@ trait TypedTreeInfo extends TreeInfo[Type] { self: Trees.Instance[Type] =>
       && tree.isTerm
       && {
         val qualType = tree.qualifier.tpe
-        hasRefinement(qualType) &&
-          !qualType.derivesFrom(defn.PolyFunctionClass) &&
-          !defn.isErasedFunctionType(qualType)
+        hasRefinement(qualType) && !defn.isRefinedFunctionType(qualType)
       }
     def loop(tree: Tree): Boolean = tree match
       case TypeApply(fun, _) =>

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

@@ -1681,7 +1681,7 @@ class Definitions {
 
   /** Is `tp` a specialized, refined function type? Either an `ErasedFunction` or a `PolyFunction`. */
   def isRefinedFunctionType(tp: Type)(using Context): Boolean =
-    (tp.typeSymbol eq defn.PolyFunctionClass) || isErasedFunctionType(tp)
+    tp.derivesFrom(defn.PolyFunctionClass) || isErasedFunctionType(tp)
 
   def isFunctionOrPolyType(tp: Type)(using Context): Boolean =
     isFunctionType(tp) || isRefinedFunctionType(tp)