Bad Query Plan with Incorrect WHERE Clause and Missing Bind Variable in Sharded Query

[systay]

The following SQL query:

select 42 
from user u 
  join user_extra ue on u.id = ue.user_id
  join music m on       m.user_id = u.id
where                   u.foo or m.foo or ue.foo

produces a bad query plan when the join predicates allow merging all three tables into the same shard query. The generated query plan includes an incorrect WHERE clause, using :m_foo without providing its value, leading to the error:

ERROR 1105 (HY000): target: foobar.replica: vttablet: rpc error: code = InvalidArgument desc = missing bind var m_foo (CallerID: x0k6a3rvhckxsk2age3k)

Query plan:

{
  "OperatorType": "Route",
  "Variant": "Scatter",
  "Keyspace": {
    "Name": "user",
    "Sharded": true
  },
  "FieldQuery": "select 42 from `user` as u, user_extra as ue, music as m where 1 != 1",
  "Query": "select 42 from `user` as u, user_extra as ue, music as m where u.id = ue.user_id and (u.foo or :m_foo or ue.foo) and m.user_id = u.id and (u.foo or m.foo or ue.foo)",
  "Table": "`user`, music, user_extra"
}