```
show functions | rename synopsis AS foo | stats bar = count(*) by foo | drop foo
```

```
{
    "error": {
        "root_cause": [
            {
                "type": "null_pointer_exception",
                "reason": "Cannot invoke \"org.elasticsearch.xpack.ql.expression.Attribute.id()\" because \"sourceAttribute\" is null"
            }
        ],
        "type": "null_pointer_exception",
        "reason": "Cannot invoke \"org.elasticsearch.xpack.ql.expression.Attribute.id()\" because \"sourceAttribute\" is null"
    },
    "status": 500
}
```

```
[2023-11-14T09:49:51,479][WARN ][r.suppressed             ] [runTask-0] path: /_query, params: {format=txt}, status: 500 java.lang.NullPointerException: Cannot invoke "org.elasticsearch.xpack.ql.expression.Attribute.id()" because "sourceAttribute" is null
        at org.elasticsearch.xpack.esql.planner.EsPhysicalOperationProviders.ordinalGroupingOperatorFactory(EsPhysicalOperationProviders.java:172)
        at org.elasticsearch.xpack.esql.planner.AbstractPhysicalOperationProviders.groupingPhysicalOperation(AbstractPhysicalOperationProviders.java:148)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planAggregation(LocalExecutionPlanner.java:234)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:182)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planAggregation(LocalExecutionPlanner.java:233)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:182)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planProject(LocalExecutionPlanner.java:571)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:196)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planLimit(LocalExecutionPlanner.java:610)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:200)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planOutput(LocalExecutionPlanner.java:310)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:224)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:168)
        at org.elasticsearch.xpack.esql.plugin.ComputeService.runCompute(ComputeService.java:260)
```
x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/optimizer/LogicalPlanOptimizerTests.java
LogicalPlan plan = optimizedPlan("""
            from test
            | eval y = emp_no + 1
            | rename y as x
            | where x > 10""");
        var keep = as(plan, Project.class);
        var limit = as(keep.child(), Limit.class);
        var filter = as(limit.child(), Filter.class);
        var attr = filter.condition().collect(Attribute.class::isInstance).stream().findFirst().get();
        assertThat(as(attr, ReferenceAttribute.class).name(), is("y"));
        var eval = as(filter.child(), Eval.class);
        as(eval.child(), EsRelation.class);
    }
    public void testPushDownFilterPastProjectUsingDissect() {
        LogicalPlan plan = optimizedPlan("""
            from test
            | dissect first_name "%{y}"
            | rename y as x
            | keep x
            | where x == "foo"
            """);
        var keep = as(plan, Project.class);
        var limit = as(keep.child(), Limit.class);
        var filter = as(limit.child(), Filter.class);
        var attr = filter.condition().collect(Attribute.class::isInstance).stream().findFirst().get();
        assertThat(as(attr, ReferenceAttribute.class).name(), is("y"));
        var dissect = as(filter.child(), Dissect.class);
        as(dissect.child(), EsRelation.class);
    }
    public void testPushDownFilterPastProjectUsingGrok() {