diff --git a/src/eval.c b/src/eval.c
index bf65082..2b145e1 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -4050,16 +4050,21 @@
 	if (**arg != '(' && alias == NULL
 				    && (paren = vim_strchr(*arg, '(')) != NULL)
 	{
+	    char_u *deref;
+
 	    *arg = name;
 	    *paren = NUL;
-	    name = deref_function_name(arg, &tofree, evalarg, verbose);
-	    if (name == NULL)
+	    deref = deref_function_name(arg, &tofree, evalarg, verbose);
+	    if (deref == NULL)
 	    {
 		*arg = name + len;
 		ret = FAIL;
 	    }
 	    else
+	    {
+		name = deref;
 		len = STRLEN(name);
+	    }
 	    *paren = '(';
 	}
 
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index a644e17..6428e63 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -3214,6 +3214,14 @@
   END
   CheckScriptSuccess(lines)
 
+  lines =<< trim END
+      vim9script
+      import './Xsquare.vim'
+
+      echo range(5)->Xsquare.NoSuchFunc()
+  END
+  CheckScriptFailure(lines, 'E1048: Item not found in script: NoSuchFunc')
+
   delete('Xsquare.vim')
 enddef
 
diff --git a/src/version.c b/src/version.c
index cff3cb8..af851d3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4128,
+/**/
     4127,
 /**/
     4126,