src/test/run-pass/generator/issue-44197.rs

   1 // Copyright 2017 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 #![feature(generators, generator_trait)]
  12
  13 use std::ops::{ Generator, GeneratorState };
  14
  15 fn foo(_: &str) -> String {
  16     String::new()
  17 }
  18
  19 fn bar(baz: String) -> impl Generator<Yield = String, Return = ()> {
  20     move || {
  21         yield foo(&baz);
  22     }
  23 }
  24
  25 fn foo2(_: &str) -> Result<String, ()> {
  26     Err(())
  27 }
  28
  29 fn bar2(baz: String) -> impl Generator<Yield = String, Return = ()> {
  30     move || {
  31         if let Ok(quux) = foo2(&baz) {
  32             yield quux;
  33         }
  34     }
  35 }
  36
  37 fn main() {
  38     unsafe {
  39         assert_eq!(bar(String::new()).resume(), GeneratorState::Yielded(String::new()));
  40         assert_eq!(bar2(String::new()).resume(), GeneratorState::Complete(()));
  41     }
  42 }