So, I’m working on a type, and would like to make it conform to
`ExpressibleByArrayLiteral`. The thing is, I don’t actually care what type
`Element` is as long as it conforms to `FixedWidthInteger` and
`UnsignedInteger`. I tried writing this:
public init <U: FixedWidthInteger & UnsignedInteger> (arrayLiteral elements:
U...) { … }
But Xcode says my type doesn’t conform to `ExpressibleByArrayLiteral` unless I
add an init that takes a concrete type:
public init(arrayLiteral elements: UInt...) { … }
Does anyone else think the generic init should to be able to satisfy
`ExpressibleByArrayLiteral` (especially since `UInt` meets the conformance
requirements)? I suspect that the compiler is complaining because the generic
init function implies that the `Element` associated type is a generic
constraint, rather than a concrete type (which maybe makes this related to
generic protocols?). I think that’s only an issue because of the current
ExpressibleBy*Literal protocols’ reliance on associated types to specify the
relevant init’s signature, though. If the protocols (or literal system) could
be re-architected so they don't need those associated types, it might make
implementing this easier. I don’t know how much work either approach would be.
Nor am I sure if it’d be better for this to be a use-case for another proposal
instead of its own thing.
- Dave Sweeris
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