<!DOCTYPE qhelp PUBLIC

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

"qhelp.dtd">

<qhelp>

<overview>

<p>

Many arithmetic or logical operators yield a trivial result when applied to

identical operands: for instance, <code>x-x</code> is zero if <code>x</code>

is a number, and <code>NaN</code> otherwise; <code>x&amp;x</code> is always

equal to <code>x</code>. Code like this is often the result of a typo, such as

misspelling a variable name.

</p>

</overview>

<recommendation>

<p>

Carefully inspect the expression to ensure it is not a symptom of a bug.

</p>

</recommendation>

<example>

<p>

In the example below, the function <code>avg</code> is intended to compute the

average of two numbers <code>x</code> and <code>y</code>. However, the programmer

accidentally used <code>x</code> twice, so the function just returns

<code>x</code>:

</p>

<sample src="RedundantExpr.go" />

<p>

This problem can be fixed by correcting the typo:

</p>

<sample src="RedundantExprGood.go" />

</example>

</qhelp>