Another "Cannot read property 'end' of null" error

[zamb3zi]

Input

function foo(arg) {
    const { y } = arg, { z, x = null } = y;
    return z ? z : null;
}

Output

TypeError: test3.js: Cannot read property 'end' of null
    at _evaluate (C:\Users\John\Documents\GitHub\babili\packages\babili\node_modules\babel-traverse\lib\path\evaluation.js:159:57)
    at evaluate (C:\Users\John\Documents\GitHub\babili\packages\babili\node_modules\babel-traverse\lib\path\evaluation.js:65:17)
    ...

REPL

The following version does not produce an exception but generates incorrect output:

Input

function foo(arg) {
    const { y } = arg, { z, x = null } = y;
    return z;
}

Output

function foo(a){const{y:b}=a;return z}

REPL

Note: removing , x = null produces correct output. Alternatively returning x + z produces correct output (REPL)

[boopathi]

#622 fixes this