20 Apr
2018
20 Apr
'18
2:39 p.m.
On Fri, Apr 20, 2018 at 08:33:10PM +0200, Marc Busqué wrote:
Not adding a type signature to `list` produces following compilation error:
[...]
(Use FlexibleContexts to permit this)
Why is that it works with concrete types but not with a type variable that takes the same concrete type in its both placeholders?
Did you try applying the suggested fix? Explicitly, add {-# LANGUAGE FlexibleContexts #-} at the top of your file to permit this.