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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:19:13 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:19:13 +0000
commit218caa410aa38c29984be31a5229b9fa717560ee (patch)
treec54bd55eeb6e4c508940a30e94c0032fbd45d677 /tests/ui/impl-trait/multiple-lifetimes/ordinary-bounds-pick-original.rs
parentReleasing progress-linux version 1.67.1+dfsg1-1~progress7.99u1. (diff)
downloadrustc-218caa410aa38c29984be31a5229b9fa717560ee.tar.xz
rustc-218caa410aa38c29984be31a5229b9fa717560ee.zip
Merging upstream version 1.68.2+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tests/ui/impl-trait/multiple-lifetimes/ordinary-bounds-pick-original.rs')
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diff --git a/tests/ui/impl-trait/multiple-lifetimes/ordinary-bounds-pick-original.rs b/tests/ui/impl-trait/multiple-lifetimes/ordinary-bounds-pick-original.rs
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+++ b/tests/ui/impl-trait/multiple-lifetimes/ordinary-bounds-pick-original.rs
@@ -0,0 +1,25 @@
+// edition:2018
+// build-pass (FIXME(62277): could be check-pass?)
+
+trait Trait<'a, 'b> {}
+impl<T> Trait<'_, '_> for T {}
+
+// Here we wind up selecting `'a` and `'b` in the hidden type because
+// those are the types that appear in the original values.
+
+fn upper_bounds<'a, 'b>(a: &'a u8, b: &'b u8) -> impl Trait<'a, 'b> {
+ // In this simple case, you have a hidden type `(&'0 u8, &'1 u8)` and constraints like
+ //
+ // ```
+ // 'a: '0
+ // 'b: '1
+ // '0 in ['a, 'b]
+ // '1 in ['a, 'b]
+ // ```
+ //
+ // We use the fact that `'a: 0'` must hold (combined with the in
+ // constraint) to determine that `'0 = 'a` must be the answer.
+ (a, b)
+}
+
+fn main() {}