Having two cases in the same switch statement or branches in the same if structure with the same
implementation is at best duplicate code, and at worst a coding error. If the same logic is truly needed for both instances, then they should be
combined.
Noncompliant Code Example
switch i {
case 1:
doFirstThing()
doSomething()
case 2:
doSomethingDifferent()
case 3: // Noncompliant; duplicates case 1's implementation
doFirstThing()
doSomething()
default:
doTheRest()
}
if a >= 0 && a < 10 {
doFirstThing()
doTheThing()
} else if a >= 10 && a < 20 {
doTheOtherThing()
} else if a >= 20 && a < 50 {
doFirstThing() // Noncompliant; duplicates first condition
doTheThing()
} else {
doTheRest()
}
Exceptions
case labels that declare variables cannot have multiple patterns. Therefore this situation is ignored.
switch a {
case .STR_CASE(let x):
print(x)
case .INT_CASE(let x):
print(x)
default:
print("default")
}
Blocks in an if chain that contain a single line of code are ignored, as are blocks in a switch statement that contain a
single line of code with or without a following break.
if a >= 0 && a < 10 { //no issue, usually this is done on purpose to increase the readability
doTheThing()
} else if a >= 10 && a < 20 {
doTheThing()
} else if a >= 20 && a < 50 {
doFirstThing()
}
But this exception does not apply to if chains without else-s, or to switch-es without default clauses when
all branches have the same single line of code. In case of if chains with else-s, or of switch-es with default
clauses, rule {rule:swift:S3923} raises a bug.
if a >= 0 && a < 10 { //Noncompliant, this might have been done on purpose but probably not
doTheThing()
} else if a >= 10 && a < 20 {
doTheThing()
}
