jshint/jshint — pull request #409 by jugglinmike (2012-01-02 23:25:28+00:00)
Title: Subscripting null references

Currently, JSHint accepts any undefined references as operands to "typeof" and "delete". While the "typeof" and "delete" operators can operate on null references, a runtime error will be thrown if an undefined variable is de-referenced. With this commit, JSHint will continue to ignore undefined variables as operands _unless_ they are de-referenced (in which case, it will throw a "not defined" error).

Example (assuming `undef` is undefined):

```javascript
// should pass
typeof undef;

// currently passes, but should not
typeof undef.attr;
````