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Diffstat (limited to 'src/test/ui/async-await/generator-not-future.rs')
-rw-r--r-- | src/test/ui/async-await/generator-not-future.rs | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/src/test/ui/async-await/generator-not-future.rs b/src/test/ui/async-await/generator-not-future.rs new file mode 100644 index 000000000..37d7cfa6f --- /dev/null +++ b/src/test/ui/async-await/generator-not-future.rs @@ -0,0 +1,45 @@ +// edition:2018 +#![feature(generators, generator_trait)] + +use std::future::Future; +use std::ops::Generator; + +async fn async_fn() {} +fn returns_async_block() -> impl Future<Output = ()> { + async {} +} +fn returns_generator() -> impl Generator<(), Yield = (), Return = ()> { + || { + let _: () = yield (); + } +} + +fn takes_future(_f: impl Future<Output = ()>) {} +fn takes_generator<ResumeTy>(_g: impl Generator<ResumeTy, Yield = (), Return = ()>) {} + +fn main() { + // okay: + takes_future(async_fn()); + takes_future(returns_async_block()); + takes_future(async {}); + takes_generator(returns_generator()); + takes_generator(|| { + let _: () = yield (); + }); + + // async futures are not generators: + takes_generator(async_fn()); + //~^ ERROR the trait bound + takes_generator(returns_async_block()); + //~^ ERROR the trait bound + takes_generator(async {}); + //~^ ERROR the trait bound + + // generators are not futures: + takes_future(returns_generator()); + //~^ ERROR is not a future + takes_future(|ctx| { + //~^ ERROR is not a future + ctx = yield (); + }); +} |