//@flow

var call_me: () => void = () => {};

function g(x: ?number) {
  var var_x = x;
  if (var_x) {
    // error: var_x might no longer be truthy when call_me is called
    call_me = () => {
      var y: number = var_x;
    }; // error
  }
  var_x = null;
}

function havoc_uninitialized() {
  var x: void | number;

  function havoc() {
    x = undefined;
  }
  havoc();
  x as void; // should error
}

function havoc_annotated() {
  var x: number | string = 42;
  function havoc() {
    x = 'hello';
  }
  if (typeof x === 'number') {
    havoc();
    x as number; // should fail
  }
}

function test_unsealed() {
  // unsealed objects are unsound
  let x = {};

  function f(g: {b: string}) {
    return {...g, ...x}; // no error here
  }

  function g() {
    x = {a: 42} as {a: number, ...}; // error here
  }
}

function param(cf: ?number) {
  cf = cf; // no error, ofc
}

function branch_error() {
  const f1 = (y: empty) => 42; // error, x has number as LB
  const f2 = (y: empty) => 42; // error, x has number as LB

  declare const f: typeof f1 & typeof f2;

  function fn() {
    let fn = (x: number) => 42;
    function havoc() {
      fn = f;
    }
    fn(52);
  }
}
