Function eval_unwinding 

pub(crate) unsafe fn eval_unwinding(expr: SEXP, env: SEXP) -> SEXP

Evaluate expr in env with Rf_eval, in the caller’s R context: the condition handlers and restarts established around the .Call() stay in place, unlike under R_tryEval, whose R_ToplevelExec empties the handler and restart stacks for the duration. An R exit leaves as RUnwind (call_unwinding).

Safety

As call_unwinding; expr and env are rooted for the call, env an environment. The result is unprotected.