src/test/ui/reachable/unreachable-try-pattern.rs

   1 // check-pass
   2 #![feature(never_type, exhaustive_patterns)]
   3 #![warn(unreachable_code)]
   4 #![warn(unreachable_patterns)]
   5
   6 enum Void {}
   7
   8 impl From<Void> for i32 {
   9     fn from(v: Void) -> i32 {
  10         match v {}
  11     }
  12 }
  13
  14 fn bar(x: Result<!, i32>) -> Result<u32, i32> {
  15     x?
  16 }
  17
  18 fn foo(x: Result<!, i32>) -> Result<u32, i32> {
  19     let y = (match x { Ok(n) => Ok(n as u32), Err(e) => Err(e) })?;
  20     //~^ WARN unreachable pattern
  21     //~| WARN unreachable expression
  22     Ok(y)
  23 }
  24
  25 fn qux(x: Result<u32, Void>) -> Result<u32, i32> {
  26     Ok(x?)
  27 }
  28
  29 fn vom(x: Result<u32, Void>) -> Result<u32, i32> {
  30     let y = (match x { Ok(n) => Ok(n), Err(e) => Err(e) })?;
  31     //~^ WARN unreachable pattern
  32     Ok(y)
  33 }
  34
  35
  36 fn main() {
  37     let _ = bar(Err(123));
  38     let _ = foo(Err(123));
  39     let _ = qux(Ok(123));
  40     let _ = vom(Ok(123));
  41 }