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authorAlbert Larsan <74931857+albertlarsan68@users.noreply.github.com>2023-01-05 09:13:28 +0100
committerAlbert Larsan <74931857+albertlarsan68@users.noreply.github.com>2023-01-11 09:32:08 +0000
commitcf2dff2b1e3fa55fa5415d524200070d0d7aacfe (patch)
tree40a88d9a46aaf3e8870676eb2538378b75a263eb /tests/ui/nll/rc-loop.rs
parentca855e6e42787ecd062d81d53336fe6788ef51a9 (diff)
downloadrust-cf2dff2b1e3fa55fa5415d524200070d0d7aacfe.tar.gz
rust-cf2dff2b1e3fa55fa5415d524200070d0d7aacfe.zip
Move /src/test to /tests
Diffstat (limited to 'tests/ui/nll/rc-loop.rs')
-rw-r--r--tests/ui/nll/rc-loop.rs28
1 files changed, 28 insertions, 0 deletions
diff --git a/tests/ui/nll/rc-loop.rs b/tests/ui/nll/rc-loop.rs
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index 00000000000..e59303d1f78
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+++ b/tests/ui/nll/rc-loop.rs
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+// 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));
+}