diff --git a/src/errors.h b/src/errors.h
index 109d9e8..43a1c9b 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -3300,3 +3300,7 @@
 EXTERN char e_could_not_check_for_pending_sigalrm_str[]
 	INIT(= N_("E1289: Could not check for pending SIGALRM: %s"));
 #endif
+#ifdef FEAT_EVAL
+EXTERN char e_substitute_nesting_too_deep[]
+	INIT(= N_("E1290: substitute nesting too deep"));
+#endif