When a JIT-compiled function failed on first call, the function name
was added to _jit_warned but this was never checked before recompiling.
Closures like parse-loop create new lambda instances on each call,
each with l_compiled=None, triggering fresh compilation + failure
in an infinite loop.
Fix: check _jit_warned before attempting compilation, and mark the
lambda with jit_failed_sentinel on first-call failure so the same
instance also stops retrying.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
giles
4dde8ba684