Type inference corner case in combination of object spread with destructuring

[Jessidhia]

TypeScript Version: 2.2.0-dev.20161127

Code

declare var keyPrototype: any
declare function getKeyData(): Promise<{ key: any }>

async function getKey () {
 const { key } = {
 key: {
 ...keyPrototype
 },
 ...await getKeyData()
 }
 return key
}

Expected behavior:

Code to typecheck. The resulting key const should be a shallow copy of keyPrototype, with certain keys overridden by the result of getKeyData.

Actual behavior:

Error on the key declaration inside const { key }: "Initializer provides no value for this binding element and the binding element has no default value", despite the RHS being guaranteed to always have a key key.

[DarylCantrell]

This is probably a duplicate. In TSX file, this works fine:

const { children, ...rest} = this.props; // OK

When I try to do this, I get the same error you're seeing:

const { children, ...rest} = { // Error
 ...this.props,
 someProp: forcedValue,
}

Works if I supply a default value, but I don't think it should require one:

const { children = null, ...rest} = {
 ...this.props,
 prop: forcedValue,
}

[robyoder]

I'm having this issue as well.

[robyoder]

This appears to be fixed in version 2.7.0-dev.20171230. Perhaps by #19513? Recommend for closing.

[sandersn]

Yep, original repro works now.