Just to be circumspect, Apple's main business isn't building compilers. Their business unit which does so appears to derive some of its mandate from management's aversion to copyleft licensing. The business case for the Swift compiler is not to be the best alternative in a diverse market place but to provide tooling better than objective-C for bespoke iOS and OSX development. It falls somewhere between an inhouse application and a product for the open market.

I'm not saying there is anything wrong with that. I am only extending the line of reasoning in the comment up an abstraction layer.

I love how it's either a frustrated hack from a sleep-derived developer or a paid team. How about a patch from someone who's better at building compilers than the core team, even though he doesn't work for that company? Or how about the frustrated hack that's reviewed by the core team and still gets the feature out faster?

Oh, so that's why all open source software is terrible?

I would wager that most of the people that put the time to put these test cases together also get paid to handle these problems and build solutions. It's a giant misconception that open source is written by a bunch of hobbyists in their spare time on the weekends.

Most open source gets written by professionals employed to build something, and the open source work is part and parcel to their day job. I send patches upstream to the open source libraries and tools I use all the time. This is all happening while my employer is paying me to be on the job, and in fact is heavily supported by my employer.