Issue #4
.passive capturing a .raises result crashed hexer
Symptom
A .passive proc that captured a .raises, non-void result crashed hexer: assert n.kind == Symbol.
Root cause
The coroutine transform lifts the result local into the environment as (dot (deref env) fld) — a non-Symbol operand the assertion didn’t expect.
The fix
Copy the non-Symbol operand verbatim instead of asserting it is a Symbol. This removes the crash; full raise-across-await remains a deferred feature (see Known limits).
Files touched: hexer/constparams.nim
Verification
Covered by cps suite.