patch 9.0.1271: using sizeof() and subtract array size is tricky Commit: https://github.com/vim/vim/commit/1b438a8228a415720efb5ca1c0503f5467292e8e Author: zeertzjq <zeertzjq@outlook.com> Date: Wed Feb 1 13:11:15 2023 +0000 patch 9.0.1271: using sizeof() and subtract array size is tricky Problem: Using sizeof() and subtract array size is tricky. Solution: Use offsetof() instead. (closes https://github.com/vim/vim/issues/11926)

--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -3960,7 +3960,7 @@ set_var_const(
 			|| STRNCMP(name, "g:", 2) == 0 || var_in_autoload))
 	    goto failed;
 
-	di = alloc(sizeof(dictitem_T) + STRLEN(varname));
+	di = alloc(offsetof(dictitem_T, di_key) + STRLEN(varname) + 1);
 	if (di == NULL)
 	    goto failed;
 	STRCPY(di->di_key, varname);