Inconsistent unicode display for kinds
With :set -fprint-unicode-syntax
, the kind *
should always be printed as ★
. However the output is extremely inconsistent. Here are a few examples from ghci, and I will add more as I run across them.
:t fmap
fmap ∷ ∀ {f ∷ ★ → ★} {a} {b}. Functor f ⇒ (a → b) → f a → f b
:i fmap
class Functor (f ∷ * → *) where
fmap ∷ forall a b. (a → b) → f a → f b
-- (note that forall is also not displayed properly as ∀ here)
:k Functor
Functor ∷ (★ → ★) → Constraint
:m + GHC.Generics
:i Functor
-- (among other output)
instance ∀ (f ∷ * → ★). Functor f ⇒ Functor (Rec1 f)
-- Defined in ‘GHC.Generics’
instance Functor Par1 -- Defined in ‘GHC.Generics’
instance ∀ i (c ∷ Meta) (f ∷ * → ★). Functor f ⇒ Functor (M1 i c f)
-- Defined in ‘GHC.Generics’
instance ∀ i c. Functor (K1 i c) -- Defined in ‘GHC.Generics’
instance ∀ (f ∷ * → ★) (g ∷ * → *).
(Functor f, Functor g) ⇒
Functor (f :.: g)
-- Defined in ‘GHC.Generics’
instance ∀ (f ∷ * → ★) (g ∷ * → ★).
(Functor f, Functor g) ⇒
Functor (f :+: g)
-- Defined in ‘GHC.Generics’
instance ∀ (f ∷ * → ★) (g ∷ * → ★).
(Functor f, Functor g) ⇒
Functor (f :*: g)
-- Defined in ‘GHC.Generics’
:t datatypeName
datatypeName
∷ ∀ {d} {t ∷ ★ → (* → *) → ★ → ★} {f ∷ * → *} {a}.
Datatype ★ d ⇒
t d f a → [Char]
:i datatypeName
class Datatype k (d ∷ k) where
datatypeName ∷ forall {k1} (t ∷ k → (* → *) → k1 → *) (f ∷ *
→ *) (a ∷ k1).
t d f a → [Char]
...
-- Defined in ‘GHC.Generics’
:t (:*:)
(:*:) ∷ ∀ {g ∷ ★ → *} {p} {f ∷ ★ → *}. f p → g p → (:*:) ★ f g p
-- Note that ★ and * are reversed from what :i displays!
Note that :t datatypeName
causes a panic in 8.1; I have filed a separate bug https://ghc.haskell.org/trac/ghc/ticket/12549