How to use pattern match for overloaded enum?

[ensan-hcl (ensan)]

It compiles fine.

enum EnumOverload {
    case value(int: Int)
    case value(string: String)
    case value(bool: Bool)
}

I can use EnumOverload.value(int: 42) and the similar with no problem, but on the pattern match it cannot used.

This is the code Xcode generated for swiftch, but it causes error.

extension EnumOverload: CustomStringConvertible {
    var description: String {
        switch self {
        case .value(int: let int): return "\(int)"
        case .value(string: let string): return "\(string)"
        case .value(bool: let bool): return "\(bool)"
        }
    }
}

As far as I know, there is no way to use label on pattern match. Is it possible to use pattern match for this enum? And if it is impossible, for what this overload is allowed?

[xAlien95 (Stefano De Carolis)]

It's a known bug. SE-0155, Expired Proposal contained a detailed description of what should've happened in case of same base-name cases,

If there are no unlabeled associated values and there are multiple labeled associated values with the same arity, then an unlabeled pattern is ambiguous. Explicit labels can be used to disambiguate:

enum Buffalo {
    case buffalo(bill: String)
    case buffalo(buffalo: String)
}

switch buffalo {
case .buffalo(_): // Error, ambiguous
case .buffalo(bill: _): // Favors `buffalo(bill:)`
case .buffalo(buffalo: _): // Favors `buffalo(buffalo:)`
}

but due to the new expiration policies and the fact that SE-0155 hasn't been fully implemented in an year from its acceptance, that section has been removed. You can read more in Addressing unimplemented evolution proposals.

@Ben_Cohen

• SE-0155 is partly implemented. The portion relating to changes to pattern matching behavior will be removed. There are also some bugs in the implementation (SR-12206 and SR-12229 ) which should be treated as existing bugs in the language.

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Side note: are you able to access bugs.swift.org? For me, the website is unavailable (it's giving me a 503 error since Saturday).

[ensan-hcl (ensan)]

Thank you for reply, I didn't know how that happened. I'll read proposals and threads!

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@xAlien95

Side note: are you able to access bugs.swift.org? For me, the website is unavailable (it's giving me a 503 error since Saturday).

I can't access it either

[typesanitizer (Varun Gandhi)]

As Stefano pointed out, this feature hasn't been fully implemented. I've created [SR-14638] ☂️ Full support for overloaded enum cases (SE-0155) · Issue #56990 · apple/swift · GitHub to collect bugs related to this.