Names used in nested functions should not be flagged as unsued

[mhegazy]

function f(a) {
    function b() {
        a++;
    }
    b();
}

a should not be marked us unused

[zpdDG4gta8XKpMCd]

how is this going to work with

fiction third(x:any, y: any, z: T) : T { return z; }

[speigg]

This does not seem to be fixed yet. I'm seeing the same problem with nested (arrow) functions.

This works:

const x = 1;
setTimeout(function() { console.log(x) })

This marks x as unused (incorrectly):

const x = 1;
setTimeout(() => console.log(x))