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Date: Thu, 15 Oct 2015 17:00:31 +0100
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Subject: =?UTF-8?Q?Re:_[PHP-DEV]_[RFC]_Void_Return_Type_=28v0.2=2c_re=c3=b6p?=
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From: rowan.collins@gmail.com (Rowan Collins)

Andrea Faulds wrote on 15/10/2015 16:32:
> Hmm, this is an interesting case you've pointed out. Being able to do 
> `return some_other_void_function();` is something I've desired in 
> other languages.
>
> But what if that void function you're calling later adds a return 
> value? Now the calling function is returning a value other than null, 
> violating its type hint and producing a runtime error.

Well, fundamentally, this is true of anything short of full 
type-checking. The type safety below is self-evident:

function foo(): int { return 42; }
function wrapped_foo(): int { return foo(); }

But foo() could later be changed to this:

function foo(): string { return 'The Answer'; }

The wrapped_foo() typehint is now broken. That's not really any 
different from foo() starting off as void/returns-null and adding a 
return value.

In both cases, a static analyser could detect the discrepancy, but the 
Zend Engine will not, until the function is executed.


> It's a shame there's no "tail call this other function and discard its 
> result" construct. 

Yeah, I guess what you really want is for a void function to be able to 
"goto foo();"

Regards,
-- 
Rowan Collins
[IMSoP]