[joshstaiger]

1000 times this. I've been really enthusiastic about the idea of a modern, compiled, type safe, systems language, backed by a major tech juggernaut.

But the compiler crashes and sourcekit instability are just breathtaking (even in 3.0+). I'm surprised I haven't seen this get more attention.

I'd (somewhat) expected something like this for the first few releases, but two years in I'm starting to think the team bit off more than they can chew with the type system.

[dolguldur]

SourceKit is unbelievable! When using Xcode for most of the time (as in >50%) it causes very high CPU load and it's not uncommon for it to use >3GB of RAM.

[bendeming]

SourceKit issues fall into two categories. The source causes the compiler itself to crash (due to one of those compiler defects mentioned elsewhere in the thread), or some issue with the build configuration.

The latter category is especially nasty, and SourceKit won't inform you of this, except perhaps to crash. Oh, and that dumb bar in Xcode.

You can compile all the Swift source in your target successfully but have SourceKit choke on your build configuration. Accidentally introduce a duplicate set of headers in HEADER_SEARCH_PATHS? Degraded performance, and at worse, the compiler crashes everytime you edit text and SourceKit invokes the compiler. In cases like this the SOURCEKIT_LOGGING environment variable is your friend. Have fun combing through those logs to tease out what build option you set is causing your issue.

I spent the better part of two days sifting through SourceKit logs to figure out why a project's autocomplete wouldn't work. Yet, I wouldn't want to go back to writing Objective-C primarily. Because Swift as a language rocks.