public boolean isDef() {
		if (parent instanceof Assign) {
			final DefExpr[] defs = ((Assign) parent).defs();

			if (defs != null) {
				for (int i = 0; i < defs.length; i++) {
					if (defs[i] == this) {
						return true;
					}
				}
			}
		}

		return false;
	}