diff --git a/src/errors.h b/src/errors.h
index 0c61340..fc815ee 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -3262,4 +3262,6 @@
 #ifdef FEAT_EVAL
 EXTERN char e_string_or_function_required_for_arrow_parens_expr[]
 	INIT(= N_("E1275: String or function required for ->(expr)"));
+EXTERN char e_illegal_map_mode_string_str[]
+	INIT(= N_("E1276: Illegal map mode string: '%s'"));
 #endif