diff --git a/src/errors.h b/src/errors.h
index 3fd265f..e632d5b 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -3209,7 +3209,8 @@
 	INIT(= N_("E1261: Cannot import .vim without using \"as\""));
 EXTERN char e_cannot_import_same_script_twice_str[]
 	INIT(= N_("E1262: Cannot import the same script twice: %s"));
-// E1263 unused
+EXTERN char e_using_autoload_name_in_non_autoload_script_str[]
+	INIT(= N_("E1263: Using autoload name in a non-autoload script: %s"));
 EXTERN char e_autoload_import_cannot_use_absolute_or_relative_path[]
 	INIT(= N_("E1264: Autoload import cannot use absolute or relative path: %s"));
 EXTERN char e_cannot_use_partial_here[]
diff --git a/src/testdir/test_vim9_import.vim b/src/testdir/test_vim9_import.vim
index 6ecea56..3734709 100644
--- a/src/testdir/test_vim9_import.vim
+++ b/src/testdir/test_vim9_import.vim
@@ -1622,6 +1622,18 @@
   delete('Xdir', 'rf')
 enddef
 
+def Test_autoload_name_wring()
+  var lines =<< trim END
+     vim9script
+     def Xscriptname#Func()
+     enddef
+  END
+  writefile(lines, 'Xscriptname.vim')
+  CheckScriptFailure(lines, 'E1263:')
+
+  delete('Xscriptname')
+enddef
+
 def Test_import_autoload_postponed()
   mkdir('Xdir/autoload', 'p')
   var save_rtp = &rtp
diff --git a/src/userfunc.c b/src/userfunc.c
index 7341878..650dfc9 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -4495,6 +4495,12 @@
 		    }
 		}
 	    }
+	    else if (vim9script && vim_strchr(name, AUTOLOAD_CHAR) != NULL)
+	    {
+		semsg(_(e_using_autoload_name_in_non_autoload_script_str),
+									 name);
+		goto erret;
+	    }
 	}
 	if (var_conflict)
 	{
diff --git a/src/version.c b/src/version.c
index a9a8323..edf26ed 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4174,
+/**/
     4173,
 /**/
     4172,