It would be useful to report file:line in WT_ERR macros, because when you look at backtrace sometimes it's hard to see which line got us to err:

Given a backtrace / core, or a reported failure, how do we know what was the initial failure point in the code. We use WT_ERR macros to unwind the stack on a failure, but we do not track the failure point as such. Given a failure, or a core we should make it easier to debug the original point of failure that started the WT_ERR unwinding.

This ticket will brainstorm ideas around solving this problem.