array on LHS handled poorly

[mgerdts]

With this file:

#! /usr/bin/env node

function foo() {
    return ['a', 'b']
}

[v1, v2] = foo();
console.log([v1, v2])

jsl fails miserably

$ PYTHONPATH=.:build ./javascriptlint/jsl fail
JavaScript Lint
Developed by Matthias Miller (http://www.JavaScriptLint.com)
/home/mgerdts/javascriptlint/fail
/home/mgerdts/javascriptlint/fail(4): warning: missing semicolon
Traceback (most recent call last):
  File "./javascriptlint/jsl", line 14, in <module>
    javascriptlint.main()
  File "/home/mgerdts/javascriptlint/javascriptlint/jsl.py", line 142, in main
    profile_func(_lint, paths, conf_, options.printlisting)
  File "/home/mgerdts/javascriptlint/javascriptlint/jsl.py", line 66, in _profile_disabled
    func(*args, **kwargs)
  File "/home/mgerdts/javascriptlint/javascriptlint/jsl.py", line 32, in _lint
    lint.lint_files(paths, lint_error, conf=conf_, printpaths=printpaths)
  File "/home/mgerdts/javascriptlint/javascriptlint/lint.py", line 340, in lint_files
    lint_file(path, 'js', None)
  File "/home/mgerdts/javascriptlint/javascriptlint/lint.py", line 331, in lint_file
    _lint_script_parts(script_parts, lint_cache[normpath], _lint_error, conf, import_script)
  File "/home/mgerdts/javascriptlint/javascriptlint/lint.py", line 540, in _lint_script_parts
    report_native, report_lint, import_callback)
  File "/home/mgerdts/javascriptlint/javascriptlint/lint.py", line 495, in _lint_script_part
    _lint_node(root, visitors)
  File "/home/mgerdts/javascriptlint/javascriptlint/lint.py", line 639, in _lint_node
    _lint_node(child, visitors)
  File "/home/mgerdts/javascriptlint/javascriptlint/lint.py", line 639, in _lint_node
    _lint_node(child, visitors)
  File "/home/mgerdts/javascriptlint/javascriptlint/lint.py", line 639, in _lint_node
    _lint_node(child, visitors)
  File "/home/mgerdts/javascriptlint/javascriptlint/lint.py", line 639, in _lint_node
    _lint_node(child, visitors)
  File "/home/mgerdts/javascriptlint/javascriptlint/lint.py", line 635, in _lint_node
    visitor(node)
  File "/home/mgerdts/javascriptlint/javascriptlint/lint.py", line 569, in onpush
    ret = visitor(node)
  File "/home/mgerdts/javascriptlint/javascriptlint/warnings.py", line 417, in useless_assign
    if value and value.kind == tok.NAME and node.atom == value.atom:
UnboundLocalError: local variable 'value' referenced before assignment

From the error message, it is clear that value is used before assignment. The correct fix is dependent on node version. In older versions of node, it seems arrays on the LHS are not allowed. node v9.3.0 is fine with it.

$ node --version
v0.12.3
$ ./fail
/home/mgerdts/javascriptlint/fail:7
[v1, v2] = foo();
^
ReferenceError: Invalid left-hand side in assignment
    at exports.runInThisContext (vm.js:73:16)
    at Module._compile (module.js:443:25)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Function.Module.runMain (module.js:501:10)
    at startup (node.js:129:16)
    at node.js:814:3

# node --version
v9.3.0
[root@buglets ~]# ./fail
[ 'a', 'b' ]