Merge pull request #3567 from dotty-staging/fix-#3467

Fix #3467: Don't pre-check kinds in TypeAssigner

Author: odersky

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

@@ -13,7 +13,7 @@ import NameOps._
 import collection.mutable
 import reporting.diagnostic.Message
 import reporting.diagnostic.messages._
-import Checking.{preCheckKind, preCheckKinds, checkNoPrivateLeaks}
+import Checking.checkNoPrivateLeaks
 
 trait TypeAssigner {
   import tpd._
@@ -375,7 +375,7 @@ trait TypeAssigner {
             else if (!paramNames.contains(name))
               ctx.error(UndefinedNamedTypeParameter(name, paramNames), arg.pos)
             else
-              namedArgMap(name) = preCheckKind(arg, paramBoundsByName(name.asTypeName)).tpe
+              namedArgMap(name) = arg.tpe
 
           // Holds indexes of non-named typed arguments in paramNames
           val gapBuf = new mutable.ListBuffer[Int]
@@ -408,7 +408,7 @@ trait TypeAssigner {
           }
         }
         else {
-          val argTypes = preCheckKinds(args, pt.paramInfos).tpes
+          val argTypes = args.tpes
           if (sameLength(argTypes, paramNames)) pt.instantiate(argTypes)
           else wrongNumberOfTypeArgs(fn.tpe, pt.typeParams, args, tree.pos)
         }

tests/neg/i2771.scala

@@ -4,21 +4,16 @@ trait C { type M <: A }
 trait D { type M >: B }
 
 object Test {
-  def test(x: C with D): Unit = {
-    def f(y: x.M)(z: y.L[y.L]) = z      // error: y.L has wrong kind
-    f(new B { type L[F[_]] = F[F] })(1) // error: F has wrong kind
-  }
-
   type LB[F[_]]
 
   type LL[F[_]] <: LB[F] // ok
 
   def foo[X[_] <: Any]() = ()
-  foo[Int]()  // error: Int has wrong kind
+  foo[Int]()  // error: Type argument Int does not conform to upper bound
 
   def bar[X, Y]() = ()
-  bar[List, Int]()   // error: List has wrong kind
+  bar[List, Int]()   // error: missing type parameter(s) for List
 
-  bar[Y = List, X = Int]()  // error: List has wrong kind
+  bar[Y = List, X = Int]()  // error: missing type parameter(s) for List
 
 }

tests/neg/i2771a.scala

@@ -0,0 +1,11 @@
+trait A { type L[X] }
+trait B { type L }
+trait C { type M <: A }
+trait D { type M >: B }
+
+object Test {
+  def test(x: C with D): Unit = {
+    def f(y: x.M)(z: y.L[y.L]) = z      // error: y.L has wrong kind
+    f(new B { type L[F[_]] = F[F] })(1) // error: F has wrong kind
+  }
+}

tests/neg/kinds1.scala

@@ -0,0 +1,16 @@
+object Test {
+
+  class C[T]
+  class C2[T[X]]
+
+  class B
+
+  val x: C[C] = ??? // error: Type argument has not the same kind as its bound
+  val y: C2[C] = ???
+
+  def f[T] = ???
+
+  def f2[T[X]] = ???
+
+  f2[C]
+}

tests/neg/kinds.scala renamed to tests/neg/kinds2.scala

@@ -5,7 +5,6 @@ object Test {
 
   class B
 
-  val x: C[C] = ??? // error: missing type parameter(s)
   val y: C2[C] = ???
 
   def f[T] = ???

tests/neg/tcpoly_overloaded.scala

@@ -21,5 +21,5 @@ trait Test {
     def flatMap[S]
             (f: T => List[S], foo: Int): List[S]  = sys.error("foo")
   }
-  val l: MList[String] = moo.flatMap[String, List, Any, MList]((x: Int) => new MList("String")) // error: wrong kind
+  val l: MList[String] = moo.flatMap[String, List, Any, MList]((x: Int) => new MList("String"))
 }

tests/pos/i3467/Test_2.scala

@@ -0,0 +1,7 @@
+package collection
+
+class Test {
+  def test(xs: Array[Int]): Unit = {
+    new ArrayOps(xs)
+  }
+}

tests/pos/i3467/collection_1.scala

@@ -0,0 +1,21 @@
+package collection
+
+abstract class WithFilter[+A, +CC[_]]
+
+trait IndexedSeq[+A] extends Any with IndexedSeqOps[A, IndexedSeq, IndexedSeq[A]]
+
+trait IndexedSeqOps[+A, +CC[X] <: IndexedSeq[X], +C] extends Any {
+  def withFilter(p: A => Boolean): WithFilter[A, CC] = ???
+}
+
+package immutable {
+  trait IndexedSeq[+A] extends collection.IndexedSeq[A] with collection.IndexedSeqOps[A, IndexedSeq, IndexedSeq[A]]
+}
+
+object ArrayOps {
+  abstract class WithFilter[A] extends collection.WithFilter[A, immutable.IndexedSeq]
+}
+
+class ArrayOps[A](val xs: Array[A]) extends AnyVal with IndexedSeqOps[A, immutable.IndexedSeq, Array[A]] {
+  override def withFilter(p: A => Boolean): ArrayOps.WithFilter[A] = ???
+}