TypeScript Version: 2.8.0-dev.2018022 or 2.7.2

Search Terms: generic keyof object literal

Code

function foo<S>(state: S, key: keyof S) {
    let newState: { [P in keyof S]: S[P] } = {[key]: state[key]};
}

Expected behavior:
Expected to compile, since I just created a simple literal object.

Actual behavior:

test.ts(2,9): error TS2322: Type '{ [x: string]: S[keyof S]; }' is not assignable to type '{ [P in keyof S]: S[P]; }'.

Seems that type is removed from key and replaced with string. I'm aware that all object keys are strings, but how do I then create an instance of Pick<S, P>?

Possibly Related Issues: #22053