Indeed, source code availability of the compiler implementation and accompanying infrastructure doesn't really matter. It takes time but it could be re-implemen

Indeed, source code availability of the compiler implementation and accompanying infrastructure doesn't really matter. It takes time but it could be re-implemented from specs. The problem with C# and .NET is (was) that they are patent-encumbered and that's the real game stopper. It took quite a long time and a lot of debate on .NET suitability for a Free Software movement to settle that matters somehow (recent releases under Apache license seem to fix many issues, though, although that still needs a statement from FSF's lawyers). I'm unaware about Swift relationship to software patents. Does anyone know?