expand

Main.purs

module Main where

import Prelude
import Unsafe.Coerce

data FOO
data BAR
data BAZ
data Run (x :: # Type) a

type LessRows r = (foo :: FOO | r)
type MoreRows = (foo :: FOO, bar :: BAR, baz :: BAZ)

foo :: forall r.  Run (LessRows r) Unit
foo = unsafeCoerce unit

foo' :: Run MoreRows Unit
foo' = expand foo

expand :: forall r1 r2 rx a. Union r1 rx r2 => Run r1 a -> Run r2 a
expand = unsafeCoerce