V3055. Suspicious assignment inside the condition expression of 'if/while/for' operator.


The analyzer detected an issue that has to do with using the assignment operator '=' with boolean operands inside the conditions of statements if/while/do while/for. It is very likely that the '==' operator was meant to be used instead.

Consider the following example:

void foo(bool b1, bool b2)
{
  if (b1 = b2)
  ....

There is a typo in this code. It will result in changing the value of variable b1 instead of comparing variables b1 and b2. The fixed version of this code should look like this:

if (b1 == b2)

If you want to do assignment inside an 'if' statement to save on code size, it is recommended that you parenthesize the assignment statement: it is a common programming technique described in books and recognized by different compilers and code analyzers.

A condition with additional parentheses tells programmers and code analyzers that there is no error:

if ((b1 = b2))

Furthermore, not only do additional parentheses make code easier to read, but they also prevent mistakes related to operation precedence, as in the following example:

if ((a = b) || a == c)
{ }

Without parentheses, the part 'b || a == c' would be evaluated first, according to operation precedence, and then the result of this expression would be assigned to variable 'a'. This behavior may be different from what the programmer expected.

According to Common Weakness Enumeration, potential errors found by using this diagnostic are classified as CWE-481.


Bugs Found

Checked Projects
344
Collected Errors
12 970