Attachment: Download

is blocked by:

• SR-15507 Compiler crashes with "SIL verification failed: external declaration of internal SILFunction not allowed: F->isAvailableExternally()"

Issue Description:

Compiler crashes when building the SwiftKMeans target of the attached Swift package.

Build log from Xcode 13.1 toolchain: https://gist.github.com/WowbaggersLiquidLunch/6046d9783d25d83e72a31ebc7c4f1390

When building using 2021-10-27 development snapshot toolchain on Xcode, the build log produces the same error for swift-algorithm’s Intersperse.swift, Joined.swift, FlattenCollection.swift, and Indexed.swift.

Update: I reduced it to a much smaller code that reproduces the bug:

import Algorithms

public struct Foo {
    public private(set) var foos: [Int]
}

extension Foo {
    func chunkedFoos() -> [[Int]] {
        foos.chunks(ofCount: 100)
            .map { foosChunk in
                foosChunk.map { $0 }
            }
    }
}

This smaller code is also attached in the form of a Swift package "Chunking".

A copy of diagnostic messages can be found here: https://gist.github.com/WowbaggersLiquidLunch/b677ce40b3f89c5f381fb966ee0b6e5e