patch 8.2.3743: ":sign" can add a highlight group without a name Commit: https://github.com/vim/vim/commit/5e18ccc60bdddc4aa39ab039f1a7c918f29e67ce Author: Bram Moolenaar <Bram@vim.org> Date: Sun Dec 5 13:02:50 2021 +0000 patch 8.2.3743: ":sign" can add a highlight group without a name Problem: ":sign" can add a highlight group without a name. Solution: Give an error if the group name is missing. (closes https://github.com/vim/vim/issues/9280)

--- a/src/errors.h
+++ b/src/errors.h
@@ -694,3 +694,5 @@ EXTERN char e_line_number_out_of_range[]
 	INIT(= N_("E1247: Line number out of range"));
 EXTERN char e_closure_called_from_invalid_context[]
 	INIT(= N_("E1248: Closure called from invalid context"));
+EXTERN char e_group_name_missing_for_str[]
+	INIT(= N_("E1249: Group name missing for %s"));