1 files changed, 24 insertions, 0 deletions
diff --git a/tests/untried/pos/t7944.scala b/tests/untried/pos/t7944.scala
new file mode 100644
index 000000000..2fe2c5866
--- /dev/null
+++ b/tests/untried/pos/t7944.scala
@@ -0,0 +1,24 @@
+class M[+A, +B]
+
+object Test {
+  implicit class EitherOps[A, B](self: Either[A, B]) {
+    def disjunction: M[A, B] = null
+  }
+
+  def foo = {
+    val l: Either[Int, Nothing] = Left[Int, Nothing](1)
+
+    var ok = EitherOps(l).disjunction
+
+    val runawayTypeVar = l.disjunction
+
+    // reported bug:
+    // found   : M[Int,B]; required: M[Int,Nothing]
+    val assign: M[Int, Nothing] = runawayTypeVar
+
+    // variations on the theme, all failed before similarly.
+    val assign1: M[Int, Nothing] = {val temp = runawayTypeVar; temp}
+    val assign2: M[Int, String] = runawayTypeVar
+    val assign3: M[Int, Nothing] = {val temp = Left(1).disjunction; temp}
+  }
+}