Flow thinks conditional throwing leaves variables uninitialized

[sophiebits]

If I have code like the following

/* @flow */

function f(x: number): number {
    var y;
    if (x < 0) {
        throw new Error();
    } else {
        y = Math.sqrt(x);
    }
    return y;
}

then Flow complains that y (undefined) is incompatible with number because it doesn't get properly initialized. If you add y = 0; on the line after the throw then no errors are thrown – ideally Flow would recognize the semantics of the throw statement here and know that the return statement isn't reached in the case that an error is thrown.

[avikchaudhuri]

Agreed. Will fix.

[gabelevi]

This was fixed awhile ago, sorry that we neglected to close the issue!