Merge pull request #331 from dotty-staging/fix/refined-subtyping

Fix/refined subtyping

14 files changed, 71 insertions, 67 deletions

diff --git a/tests/neg/moduleSubtyping.scala b/tests/neg/moduleSubtyping.scala
new file mode 100644
index 000000000..18e93d5ac
--- /dev/null
+++ b/tests/neg/moduleSubtyping.scala
@@ -0,0 +1,23 @@
+class C {
+
+  object o {
+
+    var a: C.this.o.type = ???
+    var b: this.type = ???
+    a = b   // OK
+    b = a   // OK
+
+    var c: Test.o.type = ???
+    a = c   // error
+    b = c   // error
+    c = a   // error
+    c = b   // error
+  }
+
+}
+
+object Test extends C {
+
+
+
+}
diff --git a/tests/pending/pos/channels.scala b/tests/pending/pos/channels.scala
index b2f0cdc32..77736305f 100644
--- a/tests/pending/pos/channels.scala
+++ b/tests/pending/pos/channels.scala
@@ -1,3 +1,5 @@
+// To compile this test, we need some more elaborate GADT capabilities.
+// Not sure yet we should invest to get them.
 class Channel[a]
 
 import collection.mutable.Set
@@ -16,7 +18,7 @@ object Test extends App {
   def f[b](x: ![b]): Int = x match {
     case send: ![c] =>
       send.chan match {
-        case IC => send.data
+        case IC => send.data  // Here, from the fact that `chan` is an IC, we need to conclude that `c` is Int.
       }
   }
 }
diff --git a/tests/pending/pos/subtypcycle.scala b/tests/pending/pos/subtypcycle.scala
new file mode 100644
index 000000000..76eb7ffec
--- /dev/null
+++ b/tests/pending/pos/subtypcycle.scala
@@ -0,0 +1,10 @@
+object subtypcycle {
+  trait Y {
+    type A <: { type T >: B }
+    type B >: { type T >: A }
+  }
+
+  val y: Y = ???
+  val a: y.A = ???
+  val b: y.B = a
+}
diff --git a/tests/pending/pos/t2624.scala b/tests/pending/pos/t2624.scala
deleted file mode 100644
index 76f0e3036..000000000
--- a/tests/pending/pos/t2624.scala
+++ /dev/null
@@ -1,4 +0,0 @@
-object Test {
-  List(1).map(identity(_))
-  List(1).map(identity) // this didn't typecheck before the fix
-}
diff --git a/tests/pending/pos/t267.scala b/tests/pending/pos/t267.scala
deleted file mode 100644
index 7e5876eae..000000000
--- a/tests/pending/pos/t267.scala
+++ /dev/null
@@ -1,55 +0,0 @@
-package expAbstractData
-
-/** A base class consisting of
- *   - a root trait (i.e. abstract class) `Exp' with an `eval' function
- *   - an abstract type `exp' bounded by `Exp'
- *   - a concrete instance class `Num' of `Exp' for numeric literals
- */
-trait Base {
-  type exp <: Exp
-
-  trait Exp {
-    def eval: Int
-  }
-  class Num(v: Int) extends Exp { self: exp =>
-    val value = v
-    def eval = value
-  }
-}
-
-object testBase extends App with Base {
-  type exp = Exp
-  val term = new Num(2);
-  Console.println(term.eval)
-}
-
-/** Data extension: An extension of `Base' with `Plus' expressions
- */
-trait BasePlus extends Base {
-  class Plus(l: exp, r: exp) extends Exp { self: exp =>
-    val left = l
-    val right = r
-    def eval = left.eval + right.eval
-  }
-}
-
-/** Operation extension: An extension of `Base' with 'show' methods.
- */
-trait Show extends Base {
-  type exp <: Exp1
-
-  trait Exp1 extends Exp {
-    def show: String
-  }
-  class Num1(v: Int) extends Num(v) with Exp1 { self: exp with Num1 =>
-    def show = value.toString()
-  }
-}
-
-/** Operation extension: An extension of `BasePlus' with 'show' methods.
- */
-trait ShowPlus extends BasePlus with Show {
-  class Plus1(l: exp, r: exp) extends Plus(l, r) with Exp1 { self: exp with Plus1 =>
-    def show = left.show + " + " + right.show
-  }
-}
diff --git a/tests/pos/Patterns.scala b/tests/pos/Patterns.scala
index 54c4d8ab2..e443c2ab5 100644
--- a/tests/pos/Patterns.scala
+++ b/tests/pos/Patterns.scala
@@ -6,7 +6,7 @@ object Patterns {
   private def rebase(tp: NamedType): Type = {
     def rebaseFrom(prefix: Type): Type = ???
     tp.prefix match {
-      case RefinedThis(rt) => rebaseFrom(rt)
+      case SkolemType(rt) => rebaseFrom(rt)
       case pre: ThisType => rebaseFrom(pre)
       case _ => tp
     }
diff --git a/tests/pending/pos/bounds.scala b/tests/pos/bounds.scala
index 26bc84a1b..26bc84a1b 100644
--- a/tests/pending/pos/bounds.scala
+++ b/tests/pos/bounds.scala
diff --git a/tests/pending/pos/caseClassInMethod.scala b/tests/pos/caseClassInMethod.scala
index 958e5dd47..2e6484792 100644
--- a/tests/pending/pos/caseClassInMethod.scala
+++ b/tests/pos/caseClassInMethod.scala
@@ -1,5 +1,5 @@
 object t {
   def f = { object C; case class C(); 1 }
-  // pending: def g = { case class D(x: Int); object D; 2 }
+  def g = { case class D(x: Int); object D; 2 }
   def h = { case class E(y: Int = 10); 3 }
 }
diff --git a/tests/pending/pos/class-dependent-extension-method.scala b/tests/pos/class-dependent-extension-method.scala
index b557dfa8f..b557dfa8f 100644
--- a/tests/pending/pos/class-dependent-extension-method.scala
+++ b/tests/pos/class-dependent-extension-method.scala
diff --git a/tests/pending/pos/compound.scala b/tests/pos/compound.scala
index 60890f910..24a936f13 100644
--- a/tests/pending/pos/compound.scala
+++ b/tests/pos/compound.scala
@@ -7,3 +7,8 @@ abstract class Test {
   var xx: A with B { type T; val xz: T } = null;
   xx = yy;
 }
+
+abstract class Test2 {
+  var yy: A with B { type T; val xz: T } = null;
+  val xx: A with B { type T; val xz: T } = yy
+}
diff --git a/tests/pos/refinedSubtyping.scala b/tests/pos/refinedSubtyping.scala
index a01be181d..e6a972e1c 100644
--- a/tests/pos/refinedSubtyping.scala
+++ b/tests/pos/refinedSubtyping.scala
@@ -60,3 +60,13 @@ class Test3 {
   y = x
 
 }
+class Test4 {
+
+  abstract class A { type T; val xz: Any }
+
+  val yy: A { val xz: T } = null;
+//  val xx: A { val xz: T } = null;
+  val zz: A { val xz: T } = yy;
+
+}
+
diff --git a/tests/pos/subtyping.scala b/tests/pos/subtyping.scala
index 95e813bdd..29d830dd2 100644
--- a/tests/pos/subtyping.scala
+++ b/tests/pos/subtyping.scala
@@ -16,4 +16,17 @@ object test {
 
 }
 
+object test2 {
+
+  class A
+  class B
+
+  val x: A | B = ???
+  val y: B | A = x
+
+  val a: A & B = ???
+  val b: B & A = a
+
+}
+
 
diff --git a/tests/pos/t0674.scala b/tests/pos/t0674.scala
index 589eeec9f..a734091da 100644
--- a/tests/pos/t0674.scala
+++ b/tests/pos/t0674.scala
@@ -39,10 +39,10 @@ for(a <- Some(1);
     l <- Some(12);
     m <- Some(13);
     n <- Some(14);
-    o <- Some(15)
-//    p <- Some(16);
-//    q <- Some(17)
-//    r <- Some(18);
-//    s <- Some(19)
+    o <- Some(15);
+    p <- Some(16);
+    q <- Some(17);
+    r <- Some(18);
+    s <- Some(19)
    ) yield a)
 }
diff --git a/tests/pending/pos/t1208.scala b/tests/pos/t1208.scala
index 7b14aadca..7b14aadca 100644
--- a/tests/pending/pos/t1208.scala
+++ b/tests/pos/t1208.scala