Run compiled code with RUST_BACKTRACE=1

[jdm]

Getting output like

thread 'main' panicked at 'index out of bounds: the len is 0 but the index is 0', ../src/libcollections/vec.rs:1371
note: Run with `RUST_BACKTRACE=1` for a backtrace.

from the playground is frustrating, because there's no way to make the backtrace show up and many panics can occur in non-playground code.

[TimNN]

That is already possible today, in the settings (:gear: on the right) you can enable backtraces.

[jdm]

I feel like we should change the default, in that case.

[ghost]

Could set it to 'auto' as default, which would only show the backtrace if 'Debug' not when 'Stable'