Merge pull request #2919 from retronym/ticket/7815

SI-7815 Dealias before deeming method type as dependent

1 files changed, 30 insertions, 0 deletions

diff --git a/test/files/pos/t7815.scala b/test/files/pos/t7815.scala
new file mode 100644
index 0000000000..12a434c5b0
--- /dev/null
+++ b/test/files/pos/t7815.scala
@@ -0,0 +1,30 @@
+import language.higherKinds
+
+trait Foo[A <: AnyRef] {
+  type Repr
+  def f(a: A): Repr
+  def g(a: A): Option[Repr]
+
+  type M[X]
+  def m(a: A): M[a.type]
+
+  type Id[X] = X
+  def n(a: A): Id[(Repr, M[a.type])]
+
+}
+
+object Foo {
+  type Aux[A <: AnyRef, B] = Foo[A] { type Repr = B; type M[X] = Int }
+
+}
+
+object Main extends App {
+  def mapWithFoo[A <: AnyRef, B](as: List[A])(implicit foo: Foo.Aux[A, B]) = {
+    // Should be Eta expandable because the result type of `f` is not
+    // dependant on the value, it is just `B`.
+    as map foo.f
+    as map foo.g
+    as map foo.m
+    as map foo.n
+  }
+}