I've downloaded and installed the Xcode version of the Swift 5.7 snapshot from June 13 and set the
TOOLCHAINS environment variable such that invoking
swift --version in a newly opened Terminal instance gives me this:
Apple Swift version 5.7-dev (LLVM fc0ab39bda0c879, Swift c6bb52ea2e91c0e) Target: arm64-apple-macosx12.0
I've also selected the snapshot toolchain in Xcode 13.4.1 (13F100) so that the About screen shows "Swift 5.7 Development Snapshot 2022-...".
However, when I create a Swift package in Xcode and try to set
// swift-tools-version: 5.7 in
Package.swift, I get an error:
package '[packagename]' is using Swift tools version 5.7.0 but the installed version is 5.6.0.
Am I missing a step or doing something incorrectly, or is the inability to work with these snapshots in current release versions of Xcode documented somewhere?