PureScript Compiler error

Main.purs

module Main where

import Prelude
  
import Effect (Effect)
import Signal (Signal) as S
import Signal.DOM (Touch, touch) as S.DOM

type Touch = S.DOM.Touch
type Signal = S.Signal
type State = {
    touchs :: Array Touch
}
type DerivatedState = {
    input ::State
}

initState :: State
initState = { touchs: [] }

touch :: Effect ( Signal (Array Touch) )
touch = S.DOM.touch

initDerivatedState :: Effect DerivatedState
initDerivatedState = do
    input <- initState
    pure { input }