I've uploaded the source to https://gist.github.com/troughton/9fdecf4dc09b0406c444c28f40f80d43. It works correctly in debug mode but crashes in release mode; it's hitting an
internalInvariant on line 31 of ArrayBody.swift. (As a side note, this is a Swift 2-era program that's been lightly modified, so the code style is very out of date).
From the looks of things, it does seem like the generic parameter to
Builtin.allocWithTailElems_1 is invalid somehow, so that allocation is getting corrupted. I haven't investigated too thoroughly, though.
I'll note that I ran into an issue in the build process -
SwiftPrivatePthreadExtras can't be built because the definition of
_beginthreadex isn't found (perhaps because it's only building against the single-threaded CRT?). I disabled that target to get past the error.