CWE-563

Assignment to Variable without Use. [Bad-Coding-Practices, Improper-Adherence-To-Coding-Standards]

Required inputs: IR, StaticSemanticAnalysis

The variable's value is assigned but never used, making it a dead store. After the assignment, the variable is either assigned another value or goes out of scope. It is likely that the variable is simply vestigial, but it is also possible that the unused variable points out a bug.

Demonstrative Examples

Example 1

The following code excerpt assigns to the variable r and then overwrites the value without using it.

Example Language:C
    r = getName();
    r = getNewBuffer(buf);

Excerpts from CWE [https://cwe.mitre.org], Copyright (C) 2006-2026, the MITRE Corporation. See section 9.4. "3rd-Party Licenses" in the documentation for full details.

Possible Messages

Key	Text	Severity	Disabled
conditional_unused_def	Result of assignment is not used along some path(s)	None	True
init_used_in_other_isr	Initialization is not used except within code reached from an entry point that might be triggered by an interrupt	None	True
unused_catch_parameter	Unused implicit initialization of catch clause parameter (you can use an unnamed one instead)	None	False
unused_def	Result of assignment is not used	None	False
unused_init	Unused initialization	None	False
used_in_other_isr	Result of assignment is not used except within code reached from an entry point that might be triggered by an interrupt	None	True

Options

• This rule shares the following common options: exclude_in_macros, exclude_messages_in_system_headers, excludes, extend_exclude_to_macro_invocations, includes, justification_checker, languages, post_processing, provider, report_at, severity

• The following places define options that affect this rule: Stylechecks, Analysis-GlobalOptions

report_dead_initializations

report_dead_initializations : bool = True

Whether initializations may be reported as dead.