Sharpen structural apply test to exclude PolyFunction applies

Author: odersky

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

@@ -877,7 +877,9 @@ trait TypedTreeInfo extends TreeInfo[Type] { self: Trees.Instance[Type] =>
         case _ =>
           false
       }
-      !tree.symbol.exists && tree.isTerm && hasRefinement(tree.qualifier.tpe)
+      !tree.symbol.exists
+      && !tree.qualifier.tpe.widen.derivesFrom(defn.PolyFunctionClass)
+      && tree.isTerm && hasRefinement(tree.qualifier.tpe)
     }
     def loop(tree: Tree): Boolean = tree match
       case TypeApply(fun, _) =>

tests/neg-custom-args/fatal-warnings/structural.scala

@@ -40,7 +40,7 @@ object RClose {
 package p3 {
 
 object Test {
-  def idMap[C[_],T](m: { def map[U](f: T => U): C[U] }): C[T] = m.map(t => t) // error: polymorphic refinement method map without matching type in parent Object is no longer allowed
+  def idMap[C[_],T](m: { def map[U](f: T => U): C[U] }): C[T] = m.map(t => t) // error: polymorphic refinement method map without matching type in parent Object is no longer allowed // error: Structural access not allowed
 
   def main(args: Array[String]): Unit = {
     idMap(Some(5)) // error: type mismatch: found Some[Int], required Object{map: [U](f: Any => U): Any}

tests/pos/i15065.scala renamed to tests/neg/i15065.scala

@@ -6,7 +6,7 @@ object Test3 {
   val y: { type T = Int; def t = 4; def f(a:T) = true }  // error: illegal refinement // error: illegal refinement
     = new { type T = Int; def t = 4; def f(a:T) = true }
 
-  def h(x: { def f[T](a: T): Int }) = x.f[Int](4) // error: polymorphic refinement method ... no longer allowed
+  def h(x: { def f[T](a: T): Int }) = x.f[Int](4) // error: polymorphic refinement method ... no longer allowed // error: Structural access not allowed
 
   type A = { def foo(x: Int): Unit; def foo(x: String): Unit } // error: overloaded definition // error: overloaded definition
   type B = { val foo: Int; def foo: Int } // error: duplicate foo