Rollup merge of #143046 - RalfJung:zst-unsafe-cell, r=lcnr,oli-obk

const validation: properly ignore zero-sized UnsafeCell

Fixes https://github.com/rust-lang/rust/issues/142948
r? `@oli-obk`

1 files changed, 15 insertions, 0 deletions

diff --git a/tests/ui/consts/unsafe_cell_in_const.rs b/tests/ui/consts/unsafe_cell_in_const.rs
new file mode 100644
index 00000000000..b867ae1ba9f
--- /dev/null
+++ b/tests/ui/consts/unsafe_cell_in_const.rs
@@ -0,0 +1,15 @@
+//! Ensure we do not complain about zero-sized `UnsafeCell` in a const in any form.
+//! See <https://github.com/rust-lang/rust/issues/142948>.
+
+//@ check-pass
+use std::cell::UnsafeCell;
+
+const X1: &mut UnsafeCell<[i32; 0]> = UnsafeCell::from_mut(&mut []);
+
+const X2: &mut UnsafeCell<[i32]> = UnsafeCell::from_mut(&mut []);
+
+trait Trait {}
+impl Trait for [i32; 0] {}
+const X3: &mut UnsafeCell<dyn Trait> = UnsafeCell::from_mut(&mut []);
+
+fn main() {}