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switch-statementswift2
Matthieu Riegler
Matthieu Riegler

Reputation: 54559

Swift Switch case: Default will never be executed warning

On Xcode 7b2 with Swift 2 code, I have following:

In a switch case the compiler returns the following warning : 

Default will never be executed

The code : 

switch(type) {
  case .foo:
    return "foo"
  case .bar:
    return "bar"
  case .baz:
    return "baz"
  default:
    return "?"
}

Why would there be a warning ?

Upvotes: 23

Views: 14552

Answers (3)

Christian Aberger
Christian Aberger

Reputation: 335

I think this warning violates the open-closed principle. When you add an enum value later, the default will be missing, and you can't predict what your code will do. So you have to change also this place. Anyway, using switch() at all violates this principle.

Upvotes: 10

Qbyte
Qbyte

Reputation: 13243

This could be because type is a enum with 3 cases and the compiler knows that the switch statement is exhaustive so you don't need a default statement in order to handle all possible cases.

Upvotes: 4

Matthieu Riegler
Matthieu Riegler

Reputation: 54559

I just understood why :
The object I "switched" on is an enum and my enum only has 3 entries : .foo, .bar, baz.

The compiler gets that there is no need of a default because every possibility of the enum gets tested.

Upvotes: 61

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