Enhancement: Kind of type parameter on hover

[langston-barrett]

Enhancement: Kind of type parameter on hover

[alexwl]

HCE does show kinds of type variables, but unfortunately, not always.

For example, here https://haskell-code-explorer.mfix.io/package/base-4.11.1.0/show/Data/Functor/Sum.hs#L33 kinds of type variables are shown:

data Sum f g a = InL (f a) | InR (g a)

f :: k -> *
g :: k -> *
a :: k

haskell-code-indexer gets kinds of type constructors and type variables from the type environment (a map from Name to TyThing created by the GHC) of a module. Type constructors are always in the type environment, type variables, however, sometimes are omitted from the type environment. As far as I understand, it depends on whether the value constructor, e.g., MkFoo, is used (not just declared) somewhere in the current module.