No Fallthrough only

Fallthroughs can only be used if the case contains at least one other statement

• Identifier: no_fallthrough_only
• Enabled by default: Yes
• Supports autocorrection: No
• Kind: idiomatic
• Analyzer rule: No
• Minimum Swift compiler version: 5.0.0
• Default configuration:

  Key	Value
  severity	warning

Non Triggering Examples

switch myvar {
case 1:
    var a = 1
    fallthrough
case 2:
    var a = 2
}

switch myvar {
case "a":
    var one = 1
    var two = 2
    fallthrough
case "b": /* comment */
    var three = 3
}

switch myvar {
case 1:
    let one = 1
case 2:
    // comment
    var two = 2
}

switch myvar {
case MyFunc(x: [1, 2, YourFunc(a: 23)], y: 2):
    var three = 3
    fallthrough
default:
    var three = 4
}

switch myvar {
case .alpha:
    var one = 1
case .beta:
    var three = 3
    fallthrough
default:
    var four = 4
}

let aPoint = (1, -1)
switch aPoint {
case let (x, y) where x == y:
    let A = "A"
case let (x, y) where x == -y:
    let B = "B"
    fallthrough
default:
    let C = "C"
}

switch myvar {
case MyFun(with: { $1 }):
    let one = 1
    fallthrough
case "abc":
    let two = 2
}

switch enumInstance {
case .caseA:
    print("it's a")
case .caseB:
    fallthrough
@unknown default:
    print("it's not a")
}

Triggering Examples

switch myvar {
case 1:
    ↓fallthrough
case 2:
    var a = 1
}

switch myvar {
case 1:
    var a = 2
case 2:
    ↓fallthrough
case 3:
    var a = 3
}

switch myvar {
case 1: // comment
    ↓fallthrough
}

switch myvar {
case 1: /* multi
    line
    comment */
    ↓fallthrough
case 2:
    var a = 2
}

switch myvar {
case MyFunc(x: [1, 2, YourFunc(a: 23)], y: 2):
    ↓fallthrough
default:
    var three = 4
}

switch myvar {
case .alpha:
    var one = 1
case .beta:
    ↓fallthrough
case .gamma:
    var three = 3
default:
    var four = 4
}

let aPoint = (1, -1)
switch aPoint {
case let (x, y) where x == y:
    let A = "A"
case let (x, y) where x == -y:
    ↓fallthrough
default:
    let B = "B"
}

switch myvar {
case MyFun(with: { $1 }):
    ↓fallthrough
case "abc":
    let two = 2
}