Getting started in the book should state how to get a backtrace

[mdinger]

This is the most annoying and most useless error message ever if you don't know how to get a backtrace. The docs should state how to get one. Without a backtrace it's only helpful if you already know where the error isn't always the case.

This:

vec![1, 2][7];

Returns:

thread '<main>' panicked at 'index out of bounds: the len is 2 but the index is 7', /home/rustbuild/src/rust-buildbot/slave/stable-dist-rustc-linux/build/src/libcollections/vec.rs:1359
playpen: application terminated with error code 101

[kstep]

A better option may be not the full traceback by default, but just make panic point to user's code, not code from std, as Perl's Carp does, by unwinding stack trace up to the point where it goes out of "trusted" std code.

[kstep]

I know all the problems with unwinding, but it's already there when you print traceback anyway, why not make another step to users?

[mdinger]

Nice! Now it's at least documented.