File: src/com/google/javascript/jscomp/NodeUtil.java
Issue: side-effects analysis incorrectly removing function calls with side effects
Sample Code:
---
/** @constructor */
function Foo() {
  var self = this;
  window.setTimeout(function() {
    window.location = self.location;
  }, 0);
}

Foo.prototype.setLocation = function(loc) {
  this.location = loc;
};

(new Foo()).setLocation('http://www.google.com/');
---

The setLocation call will get removed in advanced mode.

Buggy code:
static boolean evaluatesToLocalValue(Node value, Predicate<Node> locals) {
  switch (value.getType()) {
    case Token.ASSIGN:
      // A result that is aliased by a non-local name, is the effectively the
      // same as returning a non-local name, but this doesn't matter if the
      // value is immutable.
      return NodeUtil.isImmutableValue(value.getLastChild())
          || (locals.apply(value)
              && evaluatesToLocalValue(value.getLastChild(), locals));
    case Token.COMMA:
      return evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.AND:
    case Token.OR:
      return evaluatesToLocalValue(value.getFirstChild(), locals)
         && evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.HOOK:
      return evaluatesToLocalValue(value.getFirstChild().getNext(), locals)
         && evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.INC:
    case Token.DEC:
      if (value.getBooleanProp(Node.INCRDECR_PROP)) {
        return evaluatesToLocalValue(value.getFirstChild(), locals);
      } else {
        return true;
      }
    case Token.THIS:
      return locals.apply(value);
    case Token.NAME:
      return isImmutableValue(value) || locals.apply(value);
    case Token.GETELEM:
    case Token.GETPROP:
      // There is no information about the locality of object properties.
      return locals.apply(value);
    case Token.CALL:
      return callHasLocalResult(value)
          || isToStringMethodCall(value)
          || locals.apply(value);
    case Token.NEW:
      // TODO(nicksantos): This needs to be changed so that it
      // returns true iff we're sure the value was never aliased from inside
      // the constructor (similar to callHasLocalResult)
      return true;
    case Token.FUNCTION:
    case Token.REGEXP:
    case Token.ARRAYLIT:
    case Token.OBJECTLIT:
      // Literals objects with non-literal children are allowed.
      return true;
    case Token.IN:
      // TODO(johnlenz): should IN operator be included in #isSimpleOperator?
      return true;
    default:
      // Other op force a local value:
      //  x = '' + g (x is now an local string)
      //  x -= g (x is now an local number)
      if (isAssignmentOp(value)
          || isSimpleOperator(value)
          || isImmutableValue(value)) {
        return true;
      }

      throw new IllegalStateException(
          "Unexpected expression node" + value +
          "\n parent:" + value.getParent());
  }
}

Fixed code:
static boolean evaluatesToLocalValue(Node value, Predicate<Node> locals) {
  switch (value.getType()) {
    case Token.ASSIGN:
      // A result that is aliased by a non-local name, is the effectively the
      // same as returning a non-local name, but this doesn't matter if the
      // value is immutable.
      return NodeUtil.isImmutableValue(value.getLastChild())
          || (locals.apply(value)
              && evaluatesToLocalValue(value.getLastChild(), locals));
    case Token.COMMA:
      return evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.AND:
    case Token.OR:
      return evaluatesToLocalValue(value.getFirstChild(), locals)
         && evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.HOOK:
      return evaluatesToLocalValue(value.getFirstChild().getNext(), locals)
         && evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.INC:
    case Token.DEC:
      if (value.getBooleanProp(Node.INCRDECR_PROP)) {
        return evaluatesToLocalValue(value.getFirstChild(), locals);
      } else {
        return true;
      }
    case Token.THIS:
      return locals.apply(value);
    case Token.NAME:
      return isImmutableValue(value) || locals.apply(value);
    case Token.GETELEM:
    case Token.GETPROP:
      // There is no information about the locality of object properties.
      return locals.apply(value);
    case Token.CALL:
      return callHasLocalResult(value)
          || isToStringMethodCall(value)
          || locals.apply(value);
    case Token.NEW:
      // TODO(nicksantos): This needs to be changed so that it
      // returns true iff we're sure the value was never aliased from inside
      // the constructor (similar to callHasLocalResult)
      return false;
    case Token.FUNCTION:
    case Token.REGEXP:
    case Token.ARRAYLIT:
    case Token.OBJECTLIT:
      // Literals objects with non-literal children are allowed.
      return true;
    case Token.IN:
      // TODO(johnlenz): should IN operator be included in #isSimpleOperator?
      return true;
    default:
      // Other op force a local value:
      //  x = '' + g (x is now an local string)
      //  x -= g (x is now an local number)
      if (isAssignmentOp(value)
          || isSimpleOperator(value)
          || isImmutableValue(value)) {
        return true;
      }

      throw new IllegalStateException(
          "Unexpected expression node" + value +
          "\n parent:" + value.getParent());
  }
}