Function capture 

pub fn capture<T>(f: impl FnOnce() -> T) -> (T, Vec<RCondition>)

Run f and return the conditions it queued, oldest first, instead of signalling them when the guarded call returns.

For code that queues diagnostics a caller already has: replaying the steps that built a saved object repeats warnings the object recorded. capture(f).0 discards them; each RCondition can also be inspected, queued again with RCondition::defer or raised with RCondition::raise.

use miniextendr_api::deferred_condition::capture;

let (rebuilt, warnings) = capture(|| rebuild(&snapshot));
debug_assert_eq!(warnings.len(), snapshot.warnings.len());

• Conditions queued before the block, or by enclosing calls, stay queued.
• Conditions a nested #[miniextendr] call queued were signalled when that call returned, as always.
• If f unwinds (error!, Err through a nested raise, an R error), the block’s conditions stay queued and follow the usual rules: a Rust failure signals them, an R-origin error discards them. To keep them on failure too, catch the failure inside the block: capture(|| catch_condition(|| rebuild(&snapshot))) (see catch_condition).
• Where deferred conditions are suppressed (finalizers, see the module docs), nothing is queued and the vector is empty.