Spread of type that is union of object types rejected by type checker

[Jessidhia]

TypeScript Version: 2.2.0-dev.20161127

Code

interface X {}
const x: {} | X = {}
const y = { ...x }

Actual behavior:

Error with "Spread types may only be created from object types".

Probably related to #12520.

[mhegazy]

this is another variation of #12520. both union and intersection should be allowed as targets of spread.