From d576a9b241a21740226cd32dd0c7da06bf32b46a Mon Sep 17 00:00:00 2001
From: The 8472 <git@infinite-source.de>
Date: Tue, 22 Nov 2022 20:54:10 +0100
Subject: [PATCH] add test for issue 104726

---
 library/alloc/tests/str.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/library/alloc/tests/str.rs b/library/alloc/tests/str.rs
index 9689196ef21..4d182be02c9 100644
--- a/library/alloc/tests/str.rs
+++ b/library/alloc/tests/str.rs
@@ -1631,6 +1631,18 @@ fn strslice_issue_16878() {
     assert!(!"00abc01234567890123456789abc".contains("bcabc"));
 }
 
+#[test]
+fn strslice_issue_104726() {
+    // Edge-case in the simd_contains impl.
+    // The first and last byte are the same so it backtracks by one byte
+    // which aligns with the end of the string. Previously incorrect offset calculations
+    // lead to out-of-bounds slicing.
+    #[rustfmt::skip]
+    let needle =                        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaba";
+    let haystack = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaab";
+    assert!(!haystack.contains(needle));
+}
+
 #[test]
 #[cfg_attr(miri, ignore)] // Miri is too slow
 fn test_strslice_contains() {