$ swiftlint    
Linting Swift files in current working directory
Linting 'a.swift' (1/1)
~/Desktop/a.swift:7:68: warning: Redundant Self Violation: Explicit use of 'self' is not required (redundant_self)
Done linting! Found 1 violation, 0 serious in 1 file.

$ swift a.swift
a.swift:7:68: error: reference to property 'test' in closure requires explicit use of 'self' to make capture semantics explicit
 5 | 
 6 |     func testLog() {
 7 |         Logger(subsystem: "sub", category: "cat").warning("test: \(test, privacy: .private(mask: .hash))")
   |                                                                    |- error: reference to property 'test' in closure requires explicit use of 'self' to make capture semantics explicit
   |                                                                    `- note: reference 'self.' explicitly
 8 |     }
 9 | }