<!DOCTYPE qhelp PUBLIC

"-//Semmle//qhelp//EN"

"qhelp.dtd">

<qhelp>

<overview>

<p>

A value is assigned to a location, but either that location is never read

later on, or its value is always overwritten before being read. This means

that the original assignment has no effect, and could indicate a logic error or

incomplete code.

</p>

</overview>

<recommendation>

<p>

Ensure that you check the control and data flow in the method carefully.

If a value is really not needed, consider omitting the assignment. Be careful,

though: if the right-hand side has a side-effect (like performing a method call),

it is important to keep this to preserve the overall behavior.

</p>

</recommendation>

<example>

<p>

In the following example, the return value of the call to <code>send</code> on line 2

is assigned to the local variable <code>result</code>, but then never used.

</p>

<sample src="examples/DeadStoreOfLocal.js" />

<p>

Assuming that <code>send</code> returns a status code indicating whether the operation

succeeded or not, the value of <code>result</code> should be checked, perhaps like this:

</p>

<sample src="examples/DeadStoreOfLocalGood.js" />

</example>

<references>

<li>Wikipedia: <a href="http://en.wikipedia.org/wiki/Dead_store">Dead store</a>.</li>

</references>

</qhelp>