Key can't be number in Proxy

[Jack-Works]

TypeScript Version: 3.7.x-dev.201xxxxx

Search Terms:

Code

new Proxy({}, { get(target, key) {
    // key is type number | string | symbol which is impossible.
})

Expected behavior:

key be string | symbol

Actual behavior:

key be number | string | symbol

[rbuckton]

Fixed in #35594