How to use SE-0353 features? (Constrained Existential Types)

SE-0353 has supposedly been in main for a long time now. but i can’t figure out how to enable it in SwiftPM. i’ve tried:

swiftSettings: [.unsafeFlags(
["-Xfrontend", "-enable-experimental-bound-generic-extensions", 
"-Xfrontend", "-enable-parametrized-protocol-types"
])]),

and the alternative spelling

swiftSettings: [.unsafeFlags(
["-Xfrontend", "-enable-experimental-bound-generic-extensions", 
"-Xfrontend", "-enable-parameterized-protocol-types"
])]),
1 Like

Similar question here.

Constrained existential types are enabled by default now on main, so the enable-parameterized-protocol-types option doesn't exist anymore.

2 Likes

Sure, but it's still not usable om MacOS 12.4, Xcode 13.4.1 with both the 5.7 toolchain from 14 June and the main toolchain from 17 June.

As in the link I mentioned above I too get the build error:
"runtime support for parameterized protocol types is only available in macOS 99.99.0 or newer"

Maybe this requires a MacOS 12.5 beta?