After updating react-dom to version 17 the build now includes Array.fill() which isn't supported by ie11 without polyfilling. Coming from this line. Tested with just the default cra production build to make sure it wasn't a problem with my webpack config and the same issue.

https://github.com/facebook/react/blob/96ac799eace5d989de3b4f80e6414e94a08ff77a/packages/react-reconciler/src/ReactFiberLane.js#L671

Tested using CRA on version 16.9.8 of react and react-dom which works with the production build for ie11. 


export const NoLanes: Lanes =  0b0000000000000000000000000000000;
export const NoLane: Lane =  0b0000000000000000000000000000000;
export const SyncLane: Lane =  0b0000000000000000000000000000001;
export const SyncBatchedLane: Lane =  0b0000000000000000000000000000010;
export const InputDiscreteHydrationLane: Lane =  0b0000000000000000000000000000100;
const InputDiscreteLanes: Lanes =  0b0000000000000000000000000011000;
const InputContinuousHydrationLane: Lane =  0b0000000000000000000000000100000;
const InputContinuousLanes: Lanes =  0b0000000000000000000000011000000;
export const DefaultHydrationLane: Lane =  0b0000000000000000000000100000000;
export const DefaultLanes: Lanes =  0b0000000000000000000111000000000;
const TransitionHydrationLane: Lane =  0b0000000000000000001000000000000;
const TransitionLanes: Lanes =  0b0000000001111111110000000000000;
const RetryLanes: Lanes =  0b0000011110000000000000000000000;
export const SomeRetryLane: Lanes =  0b0000010000000000000000000000000;
export const SelectiveHydrationLane: Lane =  0b0000100000000000000000000000000;
const NonIdleLanes =  0b0000111111111111111111111111111;
export const IdleHydrationLane: Lane =  0b0001000000000000000000000000000;
const IdleLanes: Lanes =  0b0110000000000000000000000000000;
export const OffscreenLane: Lane =  0b1000000000000000000000000000000;
export const NoTimestamp = -1;
let currentUpdateLanePriority: LanePriority = NoLanePriority;
export function getCurrentUpdateLanePriority(): LanePriority {
  return currentUpdateLanePriority;
}
export function setCurrentUpdateLanePriority(newLanePriority: LanePriority) {
  currentUpdateLanePriority = newLanePriority;
}
let return_highestLanePriority: LanePriority = DefaultLanePriority;
function getHighestPriorityLanes(lanes: Lanes | Lane): Lanes {
  if ((SyncLane & lanes) !== NoLanes) {