Yilei_He
(Yilei He)
1
Hi,
I found a very rare situation that closure can’t infer the type of its parameter. See the code below:
func withReference<T, Result>(_ value: inout T, _ execute: (inout T) throws -> Result) rethrows -> Result {
return try execute(&value)
}
struct Person {
var name: String
}
var p = Person(name: "a")
withReference(&p) { (v) in
v.name = "1"
}
print(p)
The code can be compiled and produce correct result in Swift 3(Xcode 8) playground, but it can’t be compiled in Swift 4(Xcode 9 beta2).
The error says:
error: bug.playground:11:7: error: type of expression is ambiguous without more context
v.name = "1"
~~^~~~
Is this related to exclusive access rule introduced to Swift 4?
Regards,
Yilei He