[swift-evolution] [Pitch] Remove type-inference for stored property

[Daniel Duan]

Neither of these works btw.

func bar(myString = “hello”)
class Baz {
  let myString = { return “hello” }()
}

> On Apr 9, 2017, at 11:26 PM, Jean-Daniel <mailing at xenonium.com> wrote:
> 
> I’m full -1 on this one. It will make the language inconsistent. How do you explain a new comer that type inference work in some case, but not in other cases, while in both the compiler is completely capable to define the type.
> 
> Why 
> 
> let myString = "hello" 
> 
> would be accepted but not 
> 
> class Foo {
> 	let myString = "hello" 
> }
> 
> 
> 
>> Le 10 avr. 2017 à 04:05, Daniel Duan via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> a écrit :
>> 
>> I’m still not sure whether *I* want this. But here’s a proposal anyways: https://gist.github.com/dduan/5017a0b0f0880d014f4ce14c4ca7fb55 <https://gist.github.com/dduan/5017a0b0f0880d014f4ce14c4ca7fb55>
>> 
>>> On Apr 7, 2017, at 12:21 AM, Daniel Duan via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>>> 
>>> Hi all,
>>> 
>>> In a discussion about inferring parameter types from default value, Slava brought up some performance problems caused by type inference for stored properties in side types:
>>> 
>>> https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170313/033882.html <https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170313/033882.html>
>>> 
>>> Towards the end, the post mentioned that some Swift team members contemplated requiring types for stored properties in type declarations. I think this idea deserves some more attention. Hence this last minute idea-floating.
>>> 
>>> In addition to solving a performance headache in implementation, there're always the general benefit of making type declartion more explicit and readable (clarity for reader should out-weigh pleasure of the author). Making the
>>> language slightly more consistent (we are not inferring types for default parameter values in function anyways).
>>> 
>>> The cons for doing this are obvious too: the inference makes the language feels more friendly and is, undoubtedly, a beloved feature for many. This would be a source breaking change.
>>> 
>>> Just thought I'd float the idea to gather some quick reaction. What do y'all think?
>>> 
>>> Daniel Duan
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>> 
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