Polysemy.Internal.CustomErrors

Documentation

type WhenStuck expr b = IfStuck expr b NoErrorFcf

Like IfStuck, but specialized to the case when you don't want to do anything if expr isn't stuck.

type FirstOrder (e :: Effect) fn = UnlessStuck e (FirstOrderErrorFcf e fn)

This constraint gives helpful error messages if you attempt to use a first-order combinator with a higher-order type.

type family (l :: k1) <> (r :: k2) :: ErrorMessage where ... infixl 5

Equations

l <> r = ToErrorMessage l :<>: ToErrorMessage r

type family (t :: k1) % (b :: k2) :: ErrorMessage where ... infixr 4

Equations

t % b = ToErrorMessage t :$$: ToErrorMessage b