From 64d98f8ee037282c35007b64c2649055c56af1db Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:19:03 +0200 Subject: Merging upstream version 1.68.2+dfsg1. Signed-off-by: Daniel Baumann --- tests/ui/nll/rc-loop.rs | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 tests/ui/nll/rc-loop.rs (limited to 'tests/ui/nll/rc-loop.rs') 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), +} + +fn find_base(mut x: Rc) -> Rc { + 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)); +} -- cgit v1.2.3