Backtraces are sometimes shorter than expected

[svenha]

For some errors, the backtrace contains only one element, where a much longer backtrace would be helpful. Is there a way to achieve this?

Example:

*** ERROR:car:
Type "pair" expected, "bnil" provided -- ()
1 bigloo-type-error@__error, objs/obj_s/Llib/error.c:2997