Rollup merge of #88507 - atsuzaki:slice-fill-maybeuninit-test, r=Ralf…

…Jung Add test case for using `slice::fill` with MaybeUninit Adds test for #87891 Looks alright? `@RalfJung` Fixes #87891
rust-lang · Sep 3, 2021 · 80b572b · 80b572b
2 parents 3ce205a + 5390ea4
commit 80b572b
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/library/core/tests/slice.rs b/library/core/tests/slice.rs
@@ -1,5 +1,6 @@
 use core::cell::Cell;
 use core::cmp::Ordering;
+use core::mem::MaybeUninit;
 use core::result::Result::{Err, Ok};
 
 #[test]
@@ -2144,3 +2145,10 @@ fn test_slice_run_destructors() {
 
     assert_eq!(x.get(), 1);
 }
+
+#[test]
+fn test_slice_fill_with_uninit() {
+    // This should not UB. See #87891
+    let mut a = [MaybeUninit::<u8>::uninit(); 10];
+    a.fill(MaybeUninit::uninit());
+}