Boolean Prefix (ARCH9007)

Key swift.naming.boolean-prefix · Severity info · Category naming

Flags Bool properties and functions whose name lacks an interrogative prefix (is/has/can/should/was/will/needs/contains/allows/supports). Cocoa delegate methods, which take their sender unlabelled and are named after it, and @discardableResult actions are excepted.

Incorrect

var active: Bool = true
func premium() -> Bool { false }

Correct

var isActive: Bool = true
func hasPremium() -> Bool { false }

Fix

Prefix Bool members with is/has/can/should so conditions read as questions.