This exposes the optimization level for a few reasons.
First, Local value numbering exposed some bad codegen. Playing with
optimiaztion level exposes this more easily.
When compiling dead code in a known unused scope, we
would generate code that tried to load invalid slots.
Make sure that unused code will still pass `janet_verify()` as
invalid code could trigger bad behavior in our optimizer or garbage
collector.
Since the code was proven dead, this would not trigger any runtime
behavior issues though.
Second, even trivial optimizations tend to break debug information. For
example, constant propogation will eliminated symbol mappings which can
be useful for debugging. By default, don't eliminate any symbol map
debug info.
Calvin Rose
6e79ac9f62