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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:03 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:03 +0000 |
commit | 64d98f8ee037282c35007b64c2649055c56af1db (patch) | |
tree | 5492bcf97fce41ee1c0b1cc2add283f3e66cdab0 /tests/ui/nll/rc-loop.rs | |
parent | Adding debian version 1.67.1+dfsg1-1. (diff) | |
download | rustc-64d98f8ee037282c35007b64c2649055c56af1db.tar.xz rustc-64d98f8ee037282c35007b64c2649055c56af1db.zip |
Merging upstream version 1.68.2+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tests/ui/nll/rc-loop.rs')
-rw-r--r-- | tests/ui/nll/rc-loop.rs | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/tests/ui/nll/rc-loop.rs b/tests/ui/nll/rc-loop.rs new file mode 100644 index 000000000..e59303d1f --- /dev/null +++ b/tests/ui/nll/rc-loop.rs @@ -0,0 +1,28 @@ +// run-pass + +// A test for something that NLL enables. It sometimes happens that +// the `while let` pattern makes some borrows from a variable (in this +// case, `x`) that you need in order to compute the next value for +// `x`. The lexical checker makes this very painful. The NLL checker +// does not. + +use std::rc::Rc; + +#[derive(Debug, PartialEq, Eq)] +enum Foo { + Base(usize), + Next(Rc<Foo>), +} + +fn find_base(mut x: Rc<Foo>) -> Rc<Foo> { + while let Foo::Next(n) = &*x { + x = n.clone(); + } + x +} + +fn main() { + let chain = Rc::new(Foo::Next(Rc::new(Foo::Base(44)))); + let base = find_base(chain); + assert_eq!(&*base, &Foo::Base(44)); +} |