File: issue-82612-return-mutable-reference.rs

package info (click to toggle)
rustc 1.85.0%2Bdfsg3-1
  • links: PTS, VCS
  • area: main
  • in suites: experimental, forky, sid, trixie
  • size: 893,396 kB
  • sloc: xml: 158,127; python: 35,830; javascript: 19,497; cpp: 19,002; sh: 17,245; ansic: 13,127; asm: 4,376; makefile: 1,051; perl: 29; lisp: 29; ruby: 19; sql: 11
file content (24 lines) | stat: -rw-r--r-- 697 bytes parent folder | download | duplicates (12)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
// Regression test for #82612.

use std::marker::PhantomData;

pub trait SparseSetIndex {
    fn sparse_set_index(&self) -> usize;
}
pub struct SparseArray<I, V = I> {
    values: Vec<Option<V>>,
    marker: PhantomData<I>,
}

impl<I: SparseSetIndex, V> SparseArray<I, V> {
    pub fn get_or_insert_with(&mut self, index: I, func: impl FnOnce() -> V) -> &mut V {
        let index = index.sparse_set_index();
        if index < self.values.len() {
            let value = unsafe { self.values.get_unchecked_mut(index) };
            value.get_or_insert_with(func) //~ ERROR mismatched types
        }
        unsafe { self.values.get_unchecked_mut(index).as_mut().unwrap() }
    }
}

fn main() {}