Merge pull request #268 from ktopley-apple/dispatch-sync-fixup-overlay

Fix warnings in DispatchQueue.sync() implementation when using a comp…
diff --git a/src/swift/Queue.swift b/src/swift/Queue.swift
index b946a80..bff1bc3 100644
--- a/src/swift/Queue.swift
+++ b/src/swift/Queue.swift
@@ -216,11 +216,13 @@
 	{
 		var result: T?
 		var error: Swift.Error?
-		fn {
-			do {
-				result = try work()
-			} catch let e {
-				error = e
+		withoutActuallyEscaping(work) { _work in
+			fn {
+				do {
+					result = try _work()
+				} catch let e {
+					error = e
+				}
 			}
 		}
 		if let e = error {