Details
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Type:
Bug
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Status: Resolved
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Priority:
Medium
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Resolution: Done
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Component/s: Compiler
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Labels:
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Environment:
Linux TrustySwift 4.2.0-27-generic #32~14.04.1-Ubuntu SMP Fri Jan 22 15:32:26 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
Welcome to Swift version 3.0.1 (swift-3.0.1-PREVIEW-2). Type :help for assistance.
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Radar URL:
Description
Swift 3.0.1 Preview 2 Regression
The compiler throws an error when arrays or varargs of closures are marked as @escaping:
helge@TrustySwift:~/dev/Swift/tmp$ swift TestIt.swift
TestIt.swift:8:28: error: @escaping attribute may only be used in function parameter position
func add(callbacks cbs: @escaping Callback...) {
~^~~~~~~~~~~~~~~~
Example which works with Swift 3.0.0:
public typealias Middleware =
( IncomingMessage, ServerResponse, @escaping Next ) -> Void
public func connect(middleware: @escaping Middleware...) -> Connect {
let app = Connect()
for m in middleware { _ = app.use(m) }
return app
}
I can remove the @escaping and it compiles just fine with 3.0.1p2, which I think is wrong. And as a matter of fact it breaks compilation with Swift 3.0.0:
/Users/helge/dev/Swift/Noze.io/Sources/connect/Module.swift:21:17: error: invalid conversion from non-escaping function of type '(IncomingMessage, ServerResponse, @escaping (Any...) -> ()) -> ()' to potentially escaping function type 'Middleware' (aka '(IncomingMessage, ServerResponse, @escaping (Any...) -> ()) -> ()')
_ = app.use(m)
^
as! Middleware
Summary: @escaping needs to be allowed again on array parameters or vararg parameters.
P.S.: This is made worse by the fact that you can't even workaround it via:
#if swift(>=3.0.1)
but that may be another bug...
