[swift-evolution] Lazy var and deinit

Vladimir.S svabox at gmail.com
Thu Apr 21 05:49:55 CDT 2016

For exactly this example, from my point of view, b.clean() is actually 
using of the "b" property. Compiler, and I, don't know what '.clean()' 
means and actually it is the same as

deinit {
   b.doSomethingCool() // << shouldn't "b" created here to process your 

But probably I understand the problem you are trying to solve.
How to check if lazy property/variable was actually initialized, so you can 
call its ".clean" only when it was really created and used. I.e. we just 
don't need to call b.clean if "b" was not even called and so was not created.

Right now I can't find a way to check this, probably I'm missing something..
So the question is : how to check if b was or was not actually "created" :
(something like)

deinit {
	if let b {


On 21.04.2016 13:27, Alexandr.moq via swift-evolution wrote:
> Should SWIFT initialize a variable in deinit method if it has not been initialized?
> For example:
> ```swift
> class A {
> 	lazy var b = B()
> 	deinit {
> 		b.clean()
> 	}
> }
> var a = A()
> a.b.doSomething() //1: variable was created
> a = A() //2: "clean" method was called for "b" variable
> a = A() //3: instance of A from step 2 should killed and "deinit" method is called. In this method "b" variable will be created, "clean" will be called and "b" will be killed. So, is it ok or better if swift doesn’t create lazy variables in deinit if variable is not created yet
> ```
> To be honest, I don’t know which topic I should use. Because I don’t know, it’s propose, bug or something else.
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