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Redundant null check due to previous dereference

ID: cpp/redundant-null-check-simple Kind: path-problem Security severity: 7.5 Severity: error Precision: high Tags: - reliability - correctness - security - external/cwe/cwe-476 Query suites: - cpp-code-scanning.qls - cpp-security-extended.qls - cpp-security-and-quality.qls

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This rule finds comparisons of a pointer to null that occur after a reference of that pointer. It’s likely either the check is not required and can be removed, or it should be moved to before the dereference so that a null pointer dereference does not occur.

Recommendation

The check should be moved to before the dereference, in a way that prevents a null pointer value from being dereferenced. If it’s clear that the pointer cannot be null, consider removing the check instead.

Example

int f(MyList *list) { list->append(1); // ... if (list != NULL) { list->append(2); } }

References