4.1 Array.isArray breaking change review

[RyanCavanaugh]

Categorizing breaks we've seen from this

#41658, #41714

type Comparable = string | undefined | Array<string>;
export function check<T extends Comparable>(a: T) {
	if (Array.isArray(a)) {
		// 4.0: m: string
		// 4.1: Error, cannot index
		const m = a[0];
	}
}

#41610

const aggregatedResults: (number[] | null | 'loading')[] = [[1, 2], null, [3, 4], 'loading', [5, 6]]
// 4.0: onlyTheArrays: number[][]
// 4:1 Error, no overload matches this
const onlyTheArrays = aggregatedResults.filter<number[]>(Array.isArray) // number[][]

[jameswilddev]

Hello! Can I just confirm this is fixed in 4.1.3 (released two days ago) as hinted above? I'm having difficulty upgrading from 4.1.2 to 4.1.3 as Array.isArray guard behaviour has changed and want to make sure that any changes I'm making are correct and not mitigations for a (temporary) tool bug.

[RyanCavanaugh]

Correct, 4.1.3 contains the revert