patch 8.2.4418: crash when using special multi-byte character Commit: https://github.com/vim/vim/commit/5921aeb5741fc6e84c870d68c7c35b93ad0c9f87 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Feb 19 11:20:12 2022 +0000 patch 8.2.4418: crash when using special multi-byte character Problem: Crash when using special multi-byte character. Solution: Don't use isalpha() for an arbitrary character.

--- a/src/charset.c
+++ b/src/charset.c
@@ -1645,6 +1645,12 @@ vim_isupper(int c)
 }
 
     int
+vim_isalpha(int c)
+{
+    return vim_islower(c) || vim_isupper(c);
+}
+
+    int
 vim_toupper(int c)
 {
     if (c <= '@')