Assertion failed when declaring bad Ltac2 Notation

[SkySkimmer]

Require Import Ltac2.Ltac2.

Ltac2 Notation y "boom" := ().
(*  Anomaly "File "plugins/ltac2/tac2entries.ml", line 1046, characters 7-13: Assertion failed." *)

this should be some error (maybe syntax error) not assert failed