Root cause: when perform fires inside a VM closure chain (call_closure_reuse),
the caller frames are saved to reuse_stack on the ACTIVE VM. But the
_cek_io_suspend_hook and _cek_eval_lambda_ref create a NEW stub VM for the
VmSuspended exception. On resume, resume_vm runs on the STUB VM which has
an empty reuse_stack — the caller frames are orphaned on the original VM.
Fix: transfer reuse_stack from _active_vm to the stub VM before raising
VmSuspended. This ensures resume_vm -> restore_reuse can find and restore
the caller's frames after async resume via _driveAsync/setTimeout.
Also restore step_limit/step_count refs dropped by bootstrap.py regeneration.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
giles
c0b001d3c2