Unexpected new line before the body of a concise arrow function

Prettier 1.15.3 Playground link

--parser babylon

Input:

expect(
  () => new GraphQLObjectType({
      field1: 'foo',
      field2: 'bar'
  })
);

Output:

expect(
  () =>
    new GraphQLObjectType({
      field1: "foo",
      field2: "bar"
    })
);

Expected behavior:

expect(
  () => new GraphQLObjectType({
      field1: 'foo',
      field2: 'bar'
  })
);

[hawkrives]

FWIW, this isn’t a result of the expect() special-casing

[ShinJustinHolly3317]

anyone working on this bug?