```
from employees | keep * | mv_expand first_name
```

throws UnresolvedException:

```
org.elasticsearch.xpack.ql.capabilities.UnresolvedException: Invalid call to attribute on an unresolved object ?*
        at org.elasticsearch.xpack.ql.expression.UnresolvedNamedExpression.toAttribute(UnresolvedNamedExpression.java:44)
        at org.elasticsearch.xpack.ql.expression.Expressions.asAttributes(Expressions.java:40)
        at org.elasticsearch.xpack.ql.plan.logical.Project.output(Project.java:62)
        at org.elasticsearch.xpack.esql.plan.logical.MvExpand.<init>(MvExpand.java:31)
        at org.elasticsearch.xpack.esql.parser.LogicalPlanBuilder.lambda$visitMvExpandCommand$3(LogicalPlanBuilder.java:154)
        at org.elasticsearch.xpack.esql.parser.LogicalPlanBuilder.visitCompositeQuery(LogicalPlanBuilder.java:89)
        at org.elasticsearch.xpack.esql.parser.LogicalPlanBuilder.visitCompositeQuery(LogicalPlanBuilder.java:66)
        at org.elasticsearch.xpack.esql.parser.EsqlBaseParser$CompositeQueryContext.accept(EsqlBaseParser.java:232)
        at org.elasticsearch.xpack.ql.parser.ParserUtils.typedParsing(ParserUtils.java:51)
        at org.elasticsearch.xpack.esql.parser.LogicalPlanBuilder.plan(LogicalPlanBuilder.java:73)
        at org.elasticsearch.xpack.esql.parser.LogicalPlanBuilder.visitSingleStatement(LogicalPlanBuilder.java:82)
        at org.elasticsearch.xpack.esql.parser.LogicalPlanBuilder.visitSingleStatement(LogicalPlanBuilder.java:66)
        at org.elasticsearch.xpack.esql.parser.EsqlBaseParser$SingleStatementContext.accept(EsqlBaseParser.java:169)
```

The problem is that MV_EXPAND tries to pre-calculate the output too early, when the resolution did not happen yet.
x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/parser/StatementParserTests.java
assertThat(where, instanceOf(Filter.class));
        Filter w = (Filter) where;
        assertThat(w.child(), equalTo(PROCESSING_CMD_INPUT));
        assertThat(Expressions.name(w.condition()), equalTo("a.b.1m.4321"));
    }
    public void testFieldQualifiedName() {
        LogicalPlan where = processingCommand("where a.b.`1m`.`4321`");
        assertThat(where, instanceOf(Filter.class));
        Filter w = (Filter) where;
        assertThat(w.child(), equalTo(PROCESSING_CMD_INPUT));
        assertThat(Expressions.name(w.condition()), equalTo("a.b.1m.4321"));
    }
    public void testQuotedName() {
        
        LogicalPlan plan = processingCommand("stats count(`my-field`) |  keep `count(``my-field``)`");
        var project = as(plan, Project.class);
        assertThat(Expressions.names(project.projections()), contains("count(`my-field`)"));
    }
    private void assertIdentifierAsIndexPattern(String identifier, String statement) {
        LogicalPlan from = statement(statement);
        assertThat(from, instanceOf(EsqlUnresolvedRelation.class));
        EsqlUnresolvedRelation table = (EsqlUnresolvedRelation) from;
        assertThat(table.table().index(), is(identifier));
    }
    private LogicalPlan statement(String e) {
        return statement(e, List.of());
    }
    private LogicalPlan statement(String e, List<TypedParamValue> params) {
        return parser.createStatement(e, params);
    }