'InlineArray' is only available in macOS 26.0 or newer

[vanvoorden (Rick van Voorden)]

@ibex

I would understand the requirement if it were to do with the concurrency system which might have a dependency on Apple silicon cores, but for a data structure I am baffled by this requirement.

I don't actually think there is a lot of precedent here that new data structures should — or can — be backdeployed.

@Jumhyn

The normal course of events, IIUC, is that new functions and methods can be freely back-deployed if they depend only on other earlier-available entrypoints, but types, protocols, and conformances cannot be back-deployed. Substantial efforts and design decisions were put in to make such back-deployment possible for the Concurrency library.

The Span types are backdeployable but AFAIK it was a lot of effort to get that working.