Contains over First not Nil

Prefer contains over first(where:) != nil and firstIndex(where:) != nil.

• Identifier: contains_over_first_not_nil
• Enabled by default: No
• Supports autocorrection: No
• Kind: performance
• Analyzer rule: No
• Minimum Swift compiler version: 5.0.0
• Default configuration:

  Key	Value
  severity	warning

Non Triggering Examples

let first = myList.first(where: { $0 % 2 == 0 })

let first = myList.first { $0 % 2 == 0 }

let firstIndex = myList.firstIndex(where: { $0 % 2 == 0 })

let firstIndex = myList.firstIndex { $0 % 2 == 0 }

Triggering Examples

↓myList.first { $0 % 2 == 0 } != nil

↓myList.first(where: { $0 % 2 == 0 }) != nil

↓myList.map { $0 + 1 }.first(where: { $0 % 2 == 0 }) != nil

↓myList.first(where: someFunction) != nil

↓myList.map { $0 + 1 }.first { $0 % 2 == 0 } != nil

(↓myList.first { $0 % 2 == 0 }) != nil

↓myList.first { $0 % 2 == 0 } == nil

↓myList.first(where: { $0 % 2 == 0 }) == nil

↓myList.map { $0 + 1 }.first(where: { $0 % 2 == 0 }) == nil

↓myList.first(where: someFunction) == nil

↓myList.map { $0 + 1 }.first { $0 % 2 == 0 } == nil

(↓myList.first { $0 % 2 == 0 }) == nil

↓myList.firstIndex { $0 % 2 == 0 } != nil

↓myList.firstIndex(where: { $0 % 2 == 0 }) != nil

↓myList.map { $0 + 1 }.firstIndex(where: { $0 % 2 == 0 }) != nil

↓myList.firstIndex(where: someFunction) != nil

↓myList.map { $0 + 1 }.firstIndex { $0 % 2 == 0 } != nil

(↓myList.firstIndex { $0 % 2 == 0 }) != nil

↓myList.firstIndex { $0 % 2 == 0 } == nil

↓myList.firstIndex(where: { $0 % 2 == 0 }) == nil

↓myList.map { $0 + 1 }.firstIndex(where: { $0 % 2 == 0 }) == nil

↓myList.firstIndex(where: someFunction) == nil

↓myList.map { $0 + 1 }.firstIndex { $0 % 2 == 0 } == nil

(↓myList.firstIndex { $0 % 2 == 0 }) == nil