> On Mar 16, 2016, at 5:02 PM, Chris Lattner <[email protected]> wrote:
>
> On Mar 16, 2016, at 4:56 PM, Joe Groff <[email protected]
> <mailto:[email protected]>> wrote:
>>> We shouldn’t infer it the requirement.
>>>
>>> Rationale: I see this as analogous (in two ways) to why we don’t infer
>>> hashability of T in:
>>>
>>> func f<T>(…) {
>>> let x : Dictionary<T, String>
>>> }
>>
>> However, we do infer the `T: Hashable` in a case like this:
>>
>> func foo<T>(x: Dictionary<T, String>) {}
>>
>> `typealias` feels similar to that to me. It doesn't have to be a global
>> analysis, just an analysis of the RHS of the typealias.
>
> I consider the RHS of the typealias to be the “body” of the type alias, and
> parameters to be part of the “signature” of the funcdecl.
I'm OK starting with the base design that constraints have to be explicit. My
gut tells me though that `typealias` is close enough syntactically to `var`
that many people will expect the inference to occur, but we can always add it
later.
-Joe
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