Spread object type checking

[PavelPZ]

TypeScript Version: 2.1.4

Code

interface IPerson {
  name: string;
}

let person: IPerson = { name: 'John' };
let person2: IPerson;

person2 = { name: 'John', age:34 }; //error!!!!
person2 = { ...person, age: 34 }; //no error!!!!

Question
Is person2 = { ...person, age: 34 }; //no error!!!! expected behavior?

[aluanhaddad]

I think this is expected behavior. These are not object literals but rather expressions that produce a value that is a subtype of their constituents.

[PavelPZ]

OK, thanks, but is there any other solution how to avoid typing errors, e.g.:

person2 = { ...person, xname: 'Charles' };

[mhegazy]

Duplicate of #12717