Don't assume types in & are sorted

Author: OlivierBlanvillain

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

@@ -2005,10 +2005,15 @@ class TypeComparer(initctx: Context) extends ConstraintHandling[AbsentContext] {
         intersecting(tp1.tp1, tp2) || intersecting(tp1.tp2, tp2)
       case (_, tp2: OrType)  =>
         intersecting(tp1, tp2.tp1) || intersecting(tp1, tp2.tp2)
+      case (tp1: AndType, tp2: AndType) =>
+        intersecting(tp1.tp1, tp2.tp1) && intersecting(tp1.tp2, tp2.tp2) ||
+        intersecting(tp1.tp1, tp2.tp2) && intersecting(tp1.tp2, tp2.tp1)
       case (tp1: AndType, _) =>
-        intersecting(tp1.tp1, tp2) && intersecting(tp1.tp2, tp2) && intersecting(tp1.tp1, tp1.tp2)
+        intersecting(tp1.tp1, tp2) && intersecting(tp1.tp2, tp2) ||
+        intersecting(tp1.tp2, tp2) && intersecting(tp1.tp1, tp2)
       case (_, tp2: AndType) =>
-        intersecting(tp1, tp2.tp1) && intersecting(tp1, tp2.tp2) && intersecting(tp2.tp1, tp2.tp2)
+        intersecting(tp1, tp2.tp1) && intersecting(tp1, tp2.tp2) ||
+        intersecting(tp1, tp2.tp2) && intersecting(tp1, tp2.tp1)
       case (tp1: TypeProxy, tp2: TypeProxy) =>
         intersecting(tp1.underlying, tp2) && intersecting(tp1, tp2.underlying)
       case (tp1: TypeProxy, _) =>

tests/neg/6314.scala

@@ -0,0 +1,14 @@
+object G {
+  final class X
+  final class Y
+
+  trait Test {
+    type Type
+    val i: Bar[Y & Type] = 1 // error
+  }
+
+  type Bar[A] = A match {
+    case X & Y => String
+    case Y => Int
+  }
+}