src/test/ui/try-block.rs

   1 // run-pass
   2
   3 #![allow(non_camel_case_types)]
   4 #![allow(dead_code)]
   5 // compile-flags: --edition 2018
   6
   7 #![feature(try_blocks)]
   8
   9 struct catch {}
  10
  11 pub fn main() {
  12     let catch_result: Option<_> = try {
  13         let x = 5;
  14         x
  15     };
  16     assert_eq!(catch_result, Some(5));
  17
  18     let mut catch = true;
  19     while catch { catch = false; }
  20     assert_eq!(catch, false);
  21
  22     catch = if catch { false } else { true };
  23     assert_eq!(catch, true);
  24
  25     match catch {
  26         _ => {}
  27     };
  28
  29     let catch_err: Result<_, i32> = try {
  30         Err(22)?;
  31         1
  32     };
  33     assert_eq!(catch_err, Err(22));
  34
  35     let catch_okay: Result<i32, i32> = try {
  36         if false { Err(25)?; }
  37         Ok::<(), i32>(())?;
  38         28
  39     };
  40     assert_eq!(catch_okay, Ok(28));
  41
  42     let catch_from_loop: Result<i32, i32> = try {
  43         for i in 0..10 {
  44             if i < 5 { Ok::<i32, i32>(i)?; } else { Err(i)?; }
  45         }
  46         22
  47     };
  48     assert_eq!(catch_from_loop, Err(5));
  49
  50     let cfg_init;
  51     let _res: Result<(), ()> = try {
  52         cfg_init = 5;
  53     };
  54     assert_eq!(cfg_init, 5);
  55
  56     let cfg_init_2;
  57     let _res: Result<(), ()> = try {
  58         cfg_init_2 = 6;
  59         Err(())?;
  60     };
  61     assert_eq!(cfg_init_2, 6);
  62
  63     let my_string = "test".to_string();
  64     let res: Result<&str, ()> = try {
  65         // Unfortunately, deref doesn't fire here (#49356)
  66         &my_string[..]
  67     };
  68     assert_eq!(res, Ok("test"));
  69
  70     let my_opt: Option<_> = try { () };
  71     assert_eq!(my_opt, Some(()));
  72
  73     let my_opt: Option<_> = try { };
  74     assert_eq!(my_opt, Some(()));
  75 }