The debug experiece of destructuring patterns in lambdas is different
across the two backends due to the IR backend moving local variables
to fields.
However, since the destructuring variable is never actually visible in
the debugger (no linenumbers in the live range of the variable), and
the variable is never used for anything other than hiding it from the
debugger, we propose that it is not actually necessary to include it
in the LVT (and in fact, could be left out of the LVT on the old
backend).
Kristoffer Andersen
18612c1ef0