From da421f55850b5f7ef7e560ec8e52b41c39ff03be Mon Sep 17 00:00:00 2001
From: Pavel Grigorenko <GrigorenkoPV@ya.ru>
Date: Tue, 27 Jan 2026 23:54:24 +0300
Subject: [PATCH] =?UTF-8?q?`const=20{=20'=CE=A3'.len=5Futf8()=20}`?=
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---
 library/alloc/src/str.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/library/alloc/src/str.rs b/library/alloc/src/str.rs
index e772ac25a95c2..8a3326c7d76a7 100644
--- a/library/alloc/src/str.rs
+++ b/library/alloc/src/str.rs
@@ -411,9 +411,8 @@ impl str {
         fn map_uppercase_sigma(from: &str, i: usize) -> char {
             // See https://www.unicode.org/versions/Unicode7.0.0/ch03.pdf#G33992
             // for the definition of `Final_Sigma`.
-            debug_assert!('Σ'.len_utf8() == 2);
             let is_word_final = case_ignorable_then_cased(from[..i].chars().rev())
-                && !case_ignorable_then_cased(from[i + 2..].chars());
+                && !case_ignorable_then_cased(from[i + const { 'Σ'.len_utf8() }..].chars());
             if is_word_final { 'ς' } else { 'σ' }
         }