If there is a path without a return, undefined should be included in the return type.

[dimvar]

In this example, we should get a warning that the first operand to minus could be number or undefined.

function f(x) {
  if (x > 1) {
    return 42;
  }
}
f(0) - 123;

[mroch]

Fixed in 0.4.0 (c6457eb#diff-c600001e37d25814dbc857496fecd26dL4060)

thanks!