Comment 1 Alex J Burke 2011-11-28 12:26:34 EST

Created attachment 207611 [details]
Minimal testcase to demonstrate bug

I think the bug comes about when the function is assigned to the global object. See the line:
GLOBAL_OBJ.foo = foo;

When it is present the variable 'read' will be incorrectly marked as never having been accessed, but commenting out the assignment above makes the warning
disappear.

Comment 2 Victor Homyakov 2011-11-29 06:02:47 EST

In your example variable "read" is actually never read :) - there is no invocation of bar(), so IMHO warning is absolutely correct, although there may be also some indication of dead code e.g. "bar() is never invoked directly".

On the other side, when I rewrite my example as

(function() {
  var pasteEventName = (Prototype.Browser.IE ? 'paste' : 'input'), storageKey = "mask_data";

  function setMask(element) {
    (function(element) {
      var input = element;
      if (!input.readAttribute("readonly")) {
        input.observe("mask:unmask", function() {
          input.store(storageKey, undefined).stopObserving(pasteEventName);
        });
      }
    })(element);
    return element;
  }

  setMask.storageKey = storageKey;
  window.setMask = setMask;
})();

there is assignment to global variable, setMask() is publicly accessible, and "pasteEventName" is definitely read when invoking setMask(). Commenting line

  window.setMask = setMask;

has no effect, but commenting/uncommenting line

  setMask.storageKey = storageKey;

toggles warning. Note also incorrect highlighting of "storageKey" - 1st and last appearances are highlighted separately from 2nd and 3rd.

Comment 3 Victor Homyakov 2012-02-10 09:57:56 EST

Another example:

(function() {
  var moveCaretTimer = -1;

  function setMask() {
    (function() {
      function focusEvent() {
        var moveCaret = function() {
          // empty
        };
        clearTimeout(moveCaretTimer);
        moveCaretTimer = setTimeout(moveCaret, 0);
      }
    })();
  }

  setMask.storageKey = storageKey;
})();

moveCaretTimer is marked as never read, its occurrences not highlighted.

Comment 4 Victor Homyakov 2012-06-29 05:49:28 EDT

Bug still present in Eclipse Java EE IDE for Web Developers.
Version: Juno Release
Build id: 20120322-1740

Comment 5 Alex Pogrebnyak 2013-07-12 11:50:49 EDT

Still present in Kepler

JavaScript Development Tools

Version: 1.5.0.v201301022000-7H7DFhZFC7sReqSz-frflXk
Build id: 20120820000423

Comment 6 Pieter Peeters 2014-06-24 03:56:53 EDT

Still present in Luna.

JavaScript Development Tools 1.6.0.v201405071612-7G7FFyXFBBoPc8Pvc8c0wn