// edition:2021 //check-pass #![warn(unused)] #![feature(rustc_attrs)] #![feature(btree_extract_if)] use std::collections::BTreeMap; use std::panic::{catch_unwind, AssertUnwindSafe}; fn main() { let mut map = BTreeMap::new(); map.insert("a", ()); map.insert("b", ()); map.insert("c", ()); { let mut it = map.extract_if(|_, _| true); catch_unwind(AssertUnwindSafe(|| while it.next().is_some() {})).unwrap_err(); let result = catch_unwind(AssertUnwindSafe(|| it.next())); assert!(matches!(result, Ok(None))); } { let mut it = map.extract_if(|_, _| true); catch_unwind(AssertUnwindSafe(|| while let Some(_) = it.next() {})).unwrap_err(); let result = catch_unwind(AssertUnwindSafe(|| it.next())); assert!(matches!(result, Ok(None))); } }