testsuite: Assert that testsuite ways are known
[ghc.git] / testsuite / tests / typecheck / should_compile / T4284.hs
1 {-# LANGUAGE RankNTypes #-}
2 module Test where
3
4 foo :: () -> forall b. b
5 foo = undefined
6
7 works = id foo
8
9 fails = (id) foo
10
11 -- works type checks, but fails fails with the following error
12 -- message:
13 --
14 -- Cannot match a monotype with `() -> forall b. b'
15 -- Probable cause: `foo' is applied to too few arguments
16 -- In the first argument of `(id)', namely `foo'
17 -- In the expression: (id) foo