Support bindngs of polymorphic methods

Make Bindings Any-kinded and convert PolyTypes to HKTypes as part of (toFunctionType)

Author: nicolasstucki

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

@@ -1978,8 +1978,11 @@ class Typer extends Namer
           if (ddef.symbol.annotations.exists(_.symbol == defn.InternalQuoted_patternBindHoleAnnot)) {
             val tpe = ddef.symbol.info match {
               case t: ExprType => t.resType
-              case t: PolyType => t.resultType.toFunctionType()
               case t: MethodType => t.toFunctionType()
+              case t: PolyType =>
+                HKTypeLambda(t.paramNames)(
+                    x => t.paramInfos.mapConserve(_.subst(t, x).asInstanceOf[TypeBounds]),
+                    x => t.resType.subst(t, x).toFunctionType())
               case t => t
             }
             val exprTpe = AppliedType(defn.QuotedMatchingBindingType, tpe :: Nil)

library/src/scala/quoted/matching/Binding.scala renamed to library/src-bootstrapped/scala/quoted/matching/Binding.scala

@@ -8,7 +8,7 @@ import scala.tasty.Reflection // TODO do not depend on reflection directly
  *  @param name string name of this binding
  *  @param id unique id used for equality
  */
-class Binding[+T] private[scala](val name: String, private[Binding] val id: Object) { self =>
+class Binding[T <: AnyKind] private[scala](val name: String, private[Binding] val id: Object) { self =>
 
   override def equals(obj: Any): Boolean = obj match {
     case obj: Binding[_] => obj.id == id

library/src-non-bootstrapped/scala/quoted/matching/Binding.scala

@@ -0,0 +1,34 @@
+package scala.quoted
+package matching
+
+import scala.tasty.Reflection // TODO do not depend on reflection directly
+
+/** Binding of an Expr[T] used to know if some Expr[T] is a reference to the binding
+ *
+ *  @param name string name of this binding
+ *  @param id unique id used for equality
+ */
+class Binding[T /*<: AnyKind*/] private[scala](val name: String, private[Binding] val id: Object) { self =>
+
+  override def equals(obj: Any): Boolean = obj match {
+    case obj: Binding[_] => obj.id == id
+    case _ => false
+  }
+
+  override def hashCode(): Int = id.hashCode()
+
+}
+
+object Binding {
+
+  def unapply[T](expr: Expr[T])(implicit reflect: Reflection): Option[Binding[T]] = {
+    import reflect._
+    expr.unseal match {
+      case IsIdent(ref) =>
+        val sym = ref.symbol
+        Some(new Binding[T](sym.name, sym))
+      case _ => None
+    }
+  }
+
+}

tests/pos/quotedPatterns.scala

@@ -31,10 +31,9 @@ object Test {
     case '{ def $ff(i: Int)(j: Int): Int = $z; 2 } =>
       val a: quoted.matching.Binding[Int => Int => Int] = ff
       z
-    // FIXME
-//    case '{ def `$ff`[T](i: T): Int = $z; 2 } =>
-//      val a: quoted.matching.Binding[[T] => T => Int] = ff // TODO make Binding any-kinded
-//      z
+    case '{ def $ff[T](i: T): Int = $z; 2 } =>
+      val a: quoted.matching.Binding[[T] => T => Int] = ff
+      z
     case _ => '{1}
   }
 }