src/test/mir-opt/simplify_try_if_let.rs

   1 // compile-flags: -Zmir-opt-level=1 -Zunsound-mir-opts
   2 // ignore-test
   3 // FIXME: the pass is unsound and causes ICEs in the MIR validator
   4
   5 // EMIT_MIR simplify_try_if_let.{impl#0}-append.SimplifyArmIdentity.diff
   6
   7 use std::ptr::NonNull;
   8
   9 pub struct LinkedList {
  10     head: Option<NonNull<Node>>,
  11     tail: Option<NonNull<Node>>,
  12 }
  13
  14 pub struct Node {
  15     next: Option<NonNull<Node>>,
  16 }
  17
  18 impl LinkedList {
  19     pub fn new() -> Self {
  20         Self { head: None, tail: None }
  21     }
  22
  23     pub fn append(&mut self, other: &mut Self) {
  24         match self.tail {
  25             None => {}
  26             Some(mut tail) => {
  27                 // `as_mut` is okay here because we have exclusive access to the entirety
  28                 // of both lists.
  29                 if let Some(other_head) = other.head.take() {
  30                     unsafe {
  31                         tail.as_mut().next = Some(other_head);
  32                     }
  33                 }
  34             }
  35         }
  36     }
  37 }
  38
  39 fn main() {
  40     let mut one = LinkedList::new();
  41     let mut two = LinkedList::new();
  42     one.append(&mut two);
  43 }