Provide documentation for various Swift internals
Swift is a very successful combination of a compiled language with numerous high-level features. This means that, on the one hand, the behaviour of the code is very predictable, as there’s only one widely used Swift compiler. On the other hand, many such high-level features don’t directly translate to the present hardware’s instructions and as such require substantial language runtime and compiler magic to be able to work.
Unfortunately, there is currently little to no way for a typical language user — that is, anybody who isn’t familiar with the compiler’s implementation — to get acquainted with various implications of using most of the features of Swift. One either needs to familiarise themselves with different compilation stages and representations (SIL, LLVM IR) or rely on scarce, topical information present on the Swift forums or in videos from the WWDC or the LLVM conferences. This not only contributes to users having a harder time debu