Wrong type inference with Array.map and explicit string type / union

[deftomat]

TypeScript Version: 2.9.0-rc

Search Terms: union string map

Code

interface Person {
  phoneNumbers: {
    __typename: 'PhoneNumber';
  }[];
}

function createPerson(): Person {
  return {
    phoneNumbers: [1].map(() => ({
      __typename: 'PhoneNumber'
    }))
  };
}

Expected behavior:
This code should pass with no errors.

Actual behavior:
Failed to compile with the following error.

Type '{ phoneNumbers: { __typename: string; }[]; }' is not assignable to type 'Person'.
  Types of property 'phoneNumbers' are incompatible.
    Type '{ __typename: string; }[]' is not assignable to type '{ __typename: "PhoneNumber"; }[]'.
      Type '{ __typename: string; }' is not assignable to type '{ __typename: "PhoneNumber"; }'.
        Types of property '__typename' are incompatible.
          Type 'string' is not assignable to type '"PhoneNumber"'.

Workaround

function createPerson(): Person {
  return {
    phoneNumbers: [1].map(() => ({
      __typename: 'PhoneNumber' as 'PhoneNumber'
    }))
  };
}

[mhegazy]

Looks like a duplicate of #11152

[typescript-bot]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.

[regisbsb]

This has not been fixed and I've just run into this today

[ruairiphackett]

Still seeing this issue in 4.5.2.