Apple is open sourcing Swift Build

Swift is a really cool language.

But one thing that blows my mind is that if you ever encounter an "index out of range" error, the (massive) error message that you get doesn't tell you anything about where this error occurred... no line number... no nothing...

    let a = [1]
    print(a[1])

Is all you have to do to reproduce the error.

The error looks something like that https://pastebin.com/MQV82SaR

And gives you no useful information as to how it happened or how to fix it.

compare that with Golang which tells you, it happened in main.go at line 4.

    panic: runtime error: index out of range [1] with length 1
    
    goroutine 1 [running]:
    main.main()
     /Users/username/main.go:4 +0x15
    exit status 2

EDIT: with the LLVM_SYMBOLIZER_PATH set https://pastebin.com/8M9Dbrgj this doesn't provide anything useful either.

You have a stack dump, which means you will get all the information if you symbolicate your crash report. Xcode can do it for you automatically, but some manual methods also exist.

Indeed the error report being complained about explains this and tells you how to fix it.

Maybe the friendly default would be to have the symbolicated reports on, but perhaps this has performance impact so it’s off.

> Maybe the friendly default would be to have the symbolicated reports on

As a comment just below says, the solution is quite simple:

> ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it