[swift-users] unowned self in closure in a playground

[Zhao Xin]

I think you are right on ` lifetime guaranteed to be around until the
method call completes`. But`[unowned self]` released the retain manually in
your code. Just removing `[unowned self]` part, you code will work.

Zhaoxin

On Wed, Feb 22, 2017 at 3:18 AM, Marco S Hyman via swift-users <
swift-users at swift.org> wrote:

> > The following code crashes:
> >
> > class Demo {
> >   var value = 0
> >   lazy var increment: (Int) -> Void = { [unowned self] by in
> >     self.value += by
> >     print(self.value)
> >   }
> >  }
> >
> > Demo().increment(3)
> > error: Playground execution aborted: error: Execution was interrupted,
> reason: EXC_BREAKPOINT (code=EXC_I386_BPT, subcode=0x0).
>
> value is not a static/class variable.   Without an instance of Demo it
> does not exist.  This seems to work.
>
> class Demo {
>   static var value = 0
>   lazy var increment: (Int) -> Void = { [unowned self] by in
>     value += by
>     print(value)
>   }
> }
>
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