```
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
TRUE
            ),
            statement("row a = 1 | where true | where false | where true")
        );
    }
    public void testEval() {
        assertEquals(
            new Eval(EMPTY, PROCESSING_CMD_INPUT, List.of(new Alias(EMPTY, "b", attribute("a")))),
            processingCommand("eval b = a")
        );
        assertEquals(
            new Eval(
                EMPTY,
                PROCESSING_CMD_INPUT,
                List.of(new Alias(EMPTY, "b", attribute("a")), new Alias(EMPTY, "c", new Add(EMPTY, attribute("a"), integer(1))))
            ),
            processingCommand("eval b = a, c = a + 1")
        );
    }
    public void testEvalImplicitNames() {
        assertEquals(new Eval(EMPTY, PROCESSING_CMD_INPUT, List.of(new Alias(EMPTY, "a", attribute("a")))), processingCommand("eval a"));
        assertEquals(
            new Eval(
                EMPTY,
                PROCESSING_CMD_INPUT,
                List.of(
                    new Alias(
                        EMPTY,
                        "fn(a+1)",
                        new UnresolvedFunction(EMPTY, "fn", DEFAULT, List.of(new Add(EMPTY, attribute("a"), integer(1))))