Union discrimination breaks when destructuring parameters #38020

type Action = | {type: 'add', payload: {toAdd: number}}  | {type: 'remove', payload: {toRemove: number}}

const reducerBroken = (state: number, {type, payload}: Action) => {
    switch (type) {
        case 'add':
            return state + payload.toAdd
        case 'remove':
            return state - payload.toRemove
    }
}


const reducerWorking = (state: number, action: Action) => {
    switch (action.type) {
        case 'add':
            return state + action.payload.toAdd
        case 'remove':
            return state - action.payload.toRemove
    }
}