[swift-corelibs-dev] Closure fail to infer parameter type in a rare situation

[Yilei He]

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
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