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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/try-trait/try-as-monad.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/try-trait/try-as-monad.rs')
-rw-r--r-- | src/test/ui/try-trait/try-as-monad.rs | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/src/test/ui/try-trait/try-as-monad.rs b/src/test/ui/try-trait/try-as-monad.rs new file mode 100644 index 000000000..cf09838b3 --- /dev/null +++ b/src/test/ui/try-trait/try-as-monad.rs @@ -0,0 +1,24 @@ +// run-pass + +#![feature(try_trait_v2)] + +use std::ops::Try; + +fn monad_unit<T: Try>(x: <T as Try>::Output) -> T { + T::from_output(x) +} + +fn monad_bind<T1: Try<Residual = R>, T2: Try<Residual = R>, R>( + mx: T1, + f: impl FnOnce(<T1 as Try>::Output) -> T2) +-> T2 { + let x = mx?; + f(x) +} + +fn main() { + let mx: Option<i32> = monad_unit(1); + let my = monad_bind(mx, |x| Some(x + 1)); + let mz = monad_bind(my, |x| Some(-x)); + assert_eq!(mz, Some(-2)); +} |