[SR-7432] Can't see through boxed _SwiftValue when casting from @objc Type

[tkrajacic]

Previous ID	SR-7432
Radar	rdar://problem/39415812
Original Reporter	@tkrajacic
Type	Bug
Status	Reopened
Resolution

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, Runtime
Assignee	None
Priority	Medium

md5: be79066c5a2ee131780c4b6bfd8678cb

Issue Description:

When conforming to an @objc protocol, the check using `is` can't get the original type information.

In the Playground, uncomment the @objc in front of the protocol and suddenly the check at the end doesn't pick up on the fact that the passed type is in fact a `User.Type`

import Foundation

//@objc(Exporter)
protocol Exporter: NSObjectProtocol {
var type: Any { get }
func export(item: Any)
}

struct User { var name: String }

final class UserExporter: NSObject, Exporter {
var type: Any { return User.self }
func export(item: Any) {
guard let u = item as? User else {
return print("That's not a user")
}
print("Got user: \(u.name)")
}
}

let user = User(name: "Kermit")
let exporter: Exporter = UserExporter()

if exporter.type is User.Type {
print("Correct exporter")
}
exporter.export(item: user)

[belkadan]

@swift-ci create

[tkrajacic]

Tested in Xcode 10 and Swift 4.2 and this problem still exists.

[tkrajacic]

This problem is still present in Xcode 10.2 and Swift 5!

[AnthonyLatsis]

Fixed by #33561 (test here).