ES|QL: Project optimized incorrectly due to missing references

[luigidellaquila]

LogicalVerifier fails on the following query

row  a = "foo"  | stats  b = count(a), c = count(a) by a |  dissect a "%{b}"

{
    "error": {
        "root_cause": [
            {
                "type": "illegal_state_exception",
                "reason": "Found 1 problem\nline 1:19: Plan [Project[[b{r}#1055 AS c, a{r}#1052, b{r}#1060]]] optimized incorrectly due to missing references [b{r}#1055]"
            }
        ],
        "type": "illegal_state_exception",
        "reason": "Found 1 problem\nline 1:19: Plan [Project[[b{r}#1055 AS c, a{r}#1052, b{r}#1060]]] optimized incorrectly due to missing references [b{r}#1055]"
    },
    "status": 500
}

Interestingly, disabling the LogicalVerifier the query works fine.

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[alex-spies]

Same problem with

from employees  | stats  b = count(first_name), c = count(first_name) by first_name | eval b = first_name

I suspect a problem with PushDownEval and PushDownRegexExtract.