[swift-evolution] Making capturing semantics of local

[Taylor Swift]

i use a lot of local @inline(__always) functions as a sort of weird macro so this change would be hugely source breaking. Also can you even annotate a function object as force-inlineable?

> On Oct 26, 2017, at 6:45 PM, Howard Lovatt via swift-evolution <swift-evolution at swift.org> wrote:
> 
> The issues raised about local capture by local (inner) functions are valid, likewise the discussion about the @nonescaping annotation are also valid.
> 
> Rather than expand local function syntax why not deprecate local functions completely and add the @nonescaping annotation to local closures following the argument syntax, e.g. the running example:
> 
>     
>     class A {
>         func foo() {
>             let local: @nonescaping () -> void = {
>                 bar() // Capture of self does not need to be explicit in the closure because it is non-escaping.
>             }
>             local()
>         }
>         func bar() { ... }
>     }
> 
> This is a simpler and more powerful solution (I think others have pretty much suggested the same thing in this forum but have not explicitly said get rid of local functions).
> 
>   -- Howard.
> 
>> On 27 October 2017 at 08:16, Mike Kluev via swift-evolution <swift-evolution at swift.org> wrote:
>>> On 26 October 2017 at 20:24, David Hart <david at hartbit.com> wrote:
>> 
>>> I don’t see how this makes any sense or be possible:
>>> 
>>> * It doesn’t make sense for me because local is not a member function of A.
>>> * It would cause ambiguity when trying to call another member function with the same name as the local function.
>> 
>> in the escaping contexts, "self." is currently required before the instance members (**). 
>> the idea is to require it before some local functions as well, recursively analysing what these local functions do (at the compile time).
>> 
>> /* local */ foo() {
>>     bar()
>>     variable = 1
>> }
>> 
>> ...
>> self.foo()
>> 
>> // self is required because the compiler knows what's inside, and if it were to put the content inline that would be:
>> 
>> // inlining foo pseudo code:
>>      self.bar()
>>      self.variable = 1
>> 
>> hence the compiler can figure out that in this case "self" is required before foo()
>> 
>> on the other hand:
>> 
>> /* local */ poo() {
>>     print("doesnt not capture anything")
>> }
>> 
>> here, if compiler were to use poo in the escaping context it would not require "self." before it.
>> 
>> this decision (whether to require "self." on not) can be on the use side.
>> 
>> (**) FTM, the normal instance methods that do not capture anything may as well not require "self." before them in escaping contexts:
>> 
>> /* non local */ baz() {
>>     print("doesn't capture anything")
>> }
>> 
>> Mike
>> 
>> 
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> 
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