scala> object test { type ::[A, B]; def a: Int :: Int = ???; def b: Int = a }
-- [E007] Type Mismatch Error: -------------------------------------------------
1 |object test { type ::[A, B]; def a: Int :: Int = ???; def b: Int = a }
  |                                                                   ^
  |                                                      Found:    Int :: Int
  |                                                      Required: Int
  |
  | longer explanation available when compiling with `-explain`
1 error found
