Comparison where assignment was intended¶

ID: cpp/compare-where-assign-meant
Kind: problem
Security severity: 
Severity: error
Precision: high
Tags:
   - reliability
   - correctness
   - external/cwe/cwe-482
Query suites:
   - cpp-security-and-quality.qls

Click to see the query in the CodeQL repository

This rule finds uses of the equality operator == in places where the assignment operator = would make more sense. This is a common mistake in C and C++, because of the similarity of the = and the == operator, and the fact that expressions are valid as top-level statements.

The rule flags every occurrence of an equality operator in a position where its result is discarded.

int x;
x == 4; // most likely = was intended. Otherwise this statement has no effect.
...