rust/example/gen_block_iterate.rs
2023-12-14 15:22:37 +01:00

37 lines
977 B
Rust

// Copied from https://github.com/rust-lang/rust/blob/46455dc65069387f2dc46612f13fd45452ab301a/tests/ui/coroutine/gen_block_iterate.rs
// revisions: next old
//compile-flags: --edition 2024 -Zunstable-options
//[next] compile-flags: -Znext-solver
// run-pass
#![feature(gen_blocks)]
fn foo() -> impl Iterator<Item = u32> {
gen { yield 42; for x in 3..6 { yield x } }
}
fn moved() -> impl Iterator<Item = u32> {
let mut x = "foo".to_string();
gen move {
yield 42;
if x == "foo" { return }
x.clear();
for x in 3..6 { yield x }
}
}
fn main() {
let mut iter = foo();
assert_eq!(iter.next(), Some(42));
assert_eq!(iter.next(), Some(3));
assert_eq!(iter.next(), Some(4));
assert_eq!(iter.next(), Some(5));
assert_eq!(iter.next(), None);
// `gen` blocks are fused
assert_eq!(iter.next(), None);
let mut iter = moved();
assert_eq!(iter.next(), Some(42));
assert_eq!(iter.next(), None);
}