[SR-740] dispatch_semaphore_t is not convertible to AnyObject

[drewcrawford]

Previous ID	SR-740
Radar	None
Original Reporter	@drewcrawford
Type	Bug
Status	Resolved
Resolution	Won't Do

Environment

Linux x64
swift-DEVELOPMENT-SNAPSHOT-2016-02-08-a

Additional Detail from JIRA

Votes	0
Component/s	libdispatch
Labels	Bug, Linux
Assignee	dgrove-oss (JIRA)
Priority	Medium

md5: 12999cfe1773782d3e3be803c7f86303

Issue Description:

in Darwin, the following program is legal:

import Dispatch
let a: AnyObject = dispatch_semaphore_create(0)

On Linux, it produces the error:

error: value of type 'dispatch_semaphore_t' (aka 'COpaquePointer') does not conform to specified type 'AnyObject'

[belkadan]

Hm, this could be a problem: on Linux they aren't objects.

[drewcrawford]

For background, the code motivating this bug is an Array extension:

extension RangeReplaceableCollectionType where Generator.Element : AnyObject {
    /// Remove first colleciton element that matches the given reference
    mutating func removeItemMatchingReference(object : Generator.Element) {
        if let index = self.indexOf({$0 === object}) {
            self.removeAtIndex(index)
        }
    }
}

This code can be used to remove a semaphore from an array.

It is actually quite nonintuitive to fix this code to compile on Linux (although I did), chiefly because there is nothing obvious one can replace the where Generator.Element : AnyObject with that works for dispatch_sempahore_t.

Are we not going to bridge the dispatch objects to AnyObject (e.g. not necessarily NSObject) on the Swift runtime? I know NSObject bridging isn't available, but I think AnyObject would be appropriate to bridge...

[swift-ci]

Comment by David Grove (JIRA)

I submitted #61 which fixes this issue.

[swift-ci]

Comment by David Grove (JIRA)

made obsolete by Swift 3 dispatch overlay changes.