From 64d98f8ee037282c35007b64c2649055c56af1db Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:19:03 +0200
Subject: Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../projection-two-region-trait-bound-closure.rs   | 112 +++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 tests/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs

(limited to 'tests/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs')

diff --git a/tests/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs b/tests/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs
new file mode 100644
index 000000000..7b4a3c03a
--- /dev/null
+++ b/tests/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs
@@ -0,0 +1,112 @@
+// Test cases where we constrain `<T as Anything<'a, 'b>>::AssocType`
+// to outlive `'a` and there are two bounds in the trait definition of
+// `Anything` -- i.e., we know that `AssocType` outlives `'a` and
+// `'b`. In this case, it's not clear what is the best way to satisfy
+// the trait bound, and hence we propagate it to the caller as a type
+// test.
+
+// compile-flags:-Zverbose
+
+#![allow(warnings)]
+#![feature(rustc_attrs)]
+
+use std::cell::Cell;
+
+trait Anything<'a, 'b> {
+    type AssocType: 'a + 'b;
+}
+
+fn with_signature<'a, T, F>(cell: Cell<&'a ()>, t: T, op: F)
+where
+    F: FnOnce(Cell<&'a ()>, T),
+{
+    op(cell, t)
+}
+
+fn require<'a, 'b, 'c, T>(_cell: Cell<&'a ()>, _t: T)
+where
+    T: Anything<'b, 'c>,
+    T::AssocType: 'a,
+{
+}
+
+#[rustc_regions]
+fn no_relationships_late<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T)
+where
+    T: Anything<'b, 'c>,
+{
+    with_signature(cell, t, |cell, t| require(cell, t));
+    //~^ ERROR may not live long enough
+}
+
+#[rustc_regions]
+fn no_relationships_early<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T)
+where
+    T: Anything<'b, 'c>,
+    'a: 'a,
+{
+    with_signature(cell, t, |cell, t| require(cell, t));
+    //~^ ERROR may not live long enough
+}
+
+#[rustc_regions]
+fn projection_outlives<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T)
+where
+    T: Anything<'b, 'c>,
+    T::AssocType: 'a,
+{
+    // We are projecting `<T as Anything<'b>>::AssocType`, and we know
+    // that this outlives `'a` because of the where-clause.
+
+    with_signature(cell, t, |cell, t| require(cell, t));
+}
+
+#[rustc_regions]
+fn elements_outlive1<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T)
+where
+    T: Anything<'b, 'c>,
+    'b: 'a,
+{
+    with_signature(cell, t, |cell, t| require(cell, t));
+}
+
+#[rustc_regions]
+fn elements_outlive2<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T)
+where
+    T: Anything<'b, 'c>,
+    'c: 'a,
+{
+    with_signature(cell, t, |cell, t| require(cell, t));
+}
+
+#[rustc_regions]
+fn two_regions<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
+where
+    T: Anything<'b, 'b>,
+{
+    with_signature(cell, t, |cell, t| require(cell, t));
+    //~^ ERROR lifetime may not live long enough
+}
+
+#[rustc_regions]
+fn two_regions_outlive<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
+where
+    T: Anything<'b, 'b>,
+    'b: 'a,
+{
+    with_signature(cell, t, |cell, t| require(cell, t));
+}
+
+#[rustc_regions]
+fn one_region<'a, T>(cell: Cell<&'a ()>, t: T)
+where
+    T: Anything<'a, 'a>,
+{
+    // Note that in this case the closure still propagates an external
+    // requirement between two variables in its signature, but the
+    // creator maps both those two region variables to `'a` on its
+    // side.
+    with_signature(cell, t, |cell, t| require(cell, t));
+}
+
+fn main() {}
-- 
cgit v1.2.3