Only final lazy vals can be paths.

Reason: They might be overridden by other lazy vals
that are not realizable, and therefore risk creating
bad bounds.

2 files changed, 31 insertions, 2 deletions

diff --git a/tests/neg/i1050.scala b/tests/neg/i1050.scala
index bc906f4f4..99d81c317 100644
--- a/tests/neg/i1050.scala
+++ b/tests/neg/i1050.scala
@@ -39,7 +39,7 @@ object Tiark1 {
     trait A { type L <: Nothing }
     trait B { type L >: Any}
     trait U {
-      val p: B
+      lazy val p: B
       def brand(x: Any): p.L = x // error: not final
     }
     trait V extends U {
@@ -53,7 +53,7 @@ object Tiark2 {
     trait B { type L >: Any}
     trait U {
       type X <: B
-      val p: X
+      lazy val p: X
       def brand(x: Any): p.L = x // error: not final
     }
     trait V extends U {
diff --git a/tests/neg/i1050a.scala b/tests/neg/i1050a.scala
new file mode 100644
index 000000000..47e2f0c59
--- /dev/null
+++ b/tests/neg/i1050a.scala
@@ -0,0 +1,29 @@
+object Tiark1 {
+    trait A { type L <: Nothing }
+    trait B { type L >: Any}
+    trait U {
+      val p: B
+      def brand(x: Any): p.L = x // error: not final
+    }
+    trait V extends U {
+      lazy val p: A & B = ???
+    }
+    val v = new V {}
+    v.brand("boom!")
+}
+object Tiark2 {
+    trait A { type L <: Nothing }
+    trait B { type L >: Any}
+    trait U {
+      type X <: B
+      val p: X
+      def brand(x: Any): p.L = x // error: not final
+    }
+    trait V extends U {
+      type X = B & A
+      lazy val p: X = ???
+    }
+    val v = new V {}
+    v.brand("boom!"): Nothing
+}
+