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  1.  
  2. #[derive(Debug)]
  3. struct Hoge {
  4.     id: usize,
  5.     ok: bool,
  6. }
  7.  
  8. impl Drop for Hoge {
  9.     fn drop(&mut self) {
  10.         assert!(self.ok, "must call .ok() (id: {})", self.id);
  11.     }
  12. }
  13.  
  14. impl Hoge {
  15.     fn new(id: usize) -> Self {
  16.         Self{ id, ok: false }
  17.     }
  18.     fn next(mut self, check: i32) -> Result<Self,()> {
  19.         self.ok = true;
  20.         if check < 10 {
  21.             Ok(Self{id: self.id, ok: false})
  22.         } else {
  23.             Err(())
  24.         }
  25.     }
  26.     fn ok(mut self, check: i32) -> Result<(),()> {
  27.         self.ok = true;
  28.         if check < 10 {
  29.             Ok(())
  30.         } else {
  31.             Err(())
  32.         }
  33.     }
  34. }
  35.  
  36. fn main() {
  37.     run().unwrap();
  38. }
  39.  
  40. fn run() -> Result<(),()> {
  41.     Hoge::new(1).next(5)?.next(8)?.next(4)?.ok(3)?;
  42.     Hoge::new(2).next(1)?.next(2)?;
  43.     Hoge::new(3).next(1)?.next(2)?.ok(3)?;
  44.     Hoge::new(4).next(1)?.next(2)?.ok(5)
  45. }
Runtime error #stdin #stdout #stderr 0s 5640KB
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Standard input is empty
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Standard output is empty
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thread 'main' panicked at 'must call .ok() (id: 2)', prog.rs:10:9
note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
https://ideone.com/3McKAo
language:
Rust (rust 1.56)
created:
2 years ago
visibility:
public

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