When an arrow function appears as a lone call expression arg, params hug when arrow function body is a block statement, but don't otherwise

Prettier 1.9.1
Playground link

Input:

const superLongVariable = []

const test1 = [].filter(item => superLongVariable.includes(item.veryLongAttribute) && superLongVariable.includes(item.veryLongAttribute2))

const test2 = [].filter((item, index) => superLongVariable.includes(item.veryLongAttribute) && superLongVariable.includes(item.veryLongAttribute2))

const test3 = [].filter(item => { return superLongVariable.includes(item.veryLongAttribute) && superLongVariable.includes(item.veryLongAttribute2)})

Output:

const superLongVariable = [];

const test1 = [].filter(
  item =>
    superLongVariable.includes(item.veryLongAttribute) &&
    superLongVariable.includes(item.veryLongAttribute2)
);

const test2 = [].filter(
  (item, index) =>
    superLongVariable.includes(item.veryLongAttribute) &&
    superLongVariable.includes(item.veryLongAttribute2)
);

const test3 = [].filter(item => {
  return (
    superLongVariable.includes(item.veryLongAttribute) &&
    superLongVariable.includes(item.veryLongAttribute2)
  );
});

Expected behavior:

const superLongVariable = [];

const test1 = [].filter(item =>
  superLongVariable.includes(item.veryLongAttribute) &&
  superLongVariable.includes(item.veryLongAttribute2)
);

const test2 = [].filter((item, index) =>
  superLongVariable.includes(item.veryLongAttribute) &&
  superLongVariable.includes(item.veryLongAttribute2)
);

const test3 = [].filter(item => {
  return (
    superLongVariable.includes(item.veryLongAttribute) &&
    superLongVariable.includes(item.veryLongAttribute2)
  );
});

Reproduce the formatter behavior from the linked Prettier Playground using the three JSX inputs. Compare the current output with the expected output, then trace the relevant formatting behavior and verify that lone call-expression arguments format consistently for both arrow-function body forms.