CodeQL documentation

Unreachable statement

ID: js/unreachable-statement
Kind: problem
Severity: warning
Precision: very-high
Tags:
   - maintainability
   - correctness
   - external/cwe/cwe-561
Query suites:
   - javascript-security-and-quality.qls

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An unreachable statement almost always indicates missing code or a latent bug and should be examined carefully.

Recommendation

Examine the surrounding code to determine why the statement has become unreachable. If it is no longer needed, remove the statement.

Example

In the following example, a spurious semicolon after the if condition at line 2 makes the return statement on line 4 unreachable: the function will always execute the return statement on line 3 first, so it will never reach line 4.

function f() {
	if (someCond());
		return 23;
	return 42;
}

To correct this issue, remove the spurious semicolon:

function f() {
	if (someCond())
		return 23;
	return 42;
}

References