From 3c39dc2cba7434e88e580274d20e5d4ae0f8ab1c Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Thu, 3 Aug 2023 14:14:14 +0200
Subject: [PATCH] add test checking that overlapping assignments work

---
 src/tools/miri/tests/pass/ptr_raw.rs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/tools/miri/tests/pass/ptr_raw.rs b/src/tools/miri/tests/pass/ptr_raw.rs
index 3ba0fba9a94..2f184358907 100644
--- a/src/tools/miri/tests/pass/ptr_raw.rs
+++ b/src/tools/miri/tests/pass/ptr_raw.rs
@@ -20,6 +20,15 @@ fn basic_raw() {
     assert_eq!(*x, 23);
 }
 
+fn assign_overlapping() {
+    // Test an assignment where LHS and RHS alias.
+    // In Mir, that's UB (see `fail/overlapping_assignment.rs`), but in surface Rust this is allowed.
+    let mut mem = [0u32; 4];
+    let ptr = &mut mem as *mut [u32; 4];
+    unsafe { *ptr = *ptr };
+}
+
 fn main() {
     basic_raw();
+    assign_overlapping();
 }