```
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
RLike rlike = (RLike) filter.condition();
        assertEquals(".*bar.*", rlike.pattern().asJavaRegex());
        expectError("from a | where foo like 12", "mismatched input '12'");
        expectError("from a | where foo rlike 12", "mismatched input '12'");
    }
    public void testEnrich() {
        assertEquals(
            new Enrich(EMPTY, PROCESSING_CMD_INPUT, new Literal(EMPTY, "countries", KEYWORD), new EmptyAttribute(EMPTY), null, List.of()),
            processingCommand("enrich countries")
        );
        assertEquals(
            new Enrich(
                EMPTY,
                PROCESSING_CMD_INPUT,
                new Literal(EMPTY, "countries", KEYWORD),
                new UnresolvedAttribute(EMPTY, "country_code"),
                null,
                List.of()
            ),
            processingCommand("enrich countries ON country_code")
        );
        expectError("from a | enrich countries on foo* ", "Using wildcards (*) in ENRICH WITH projections is not allowed [foo*]");
        expectError("from a | enrich countries on foo with bar*", "Using wildcards (*) in ENRICH WITH projections is not allowed [bar*]");
        expectError(
            "from a | enrich countries on foo with x = bar* ",
            "Using wildcards (*) in ENRICH WITH projections is not allowed [bar*]"
        );
        expectError(
            "from a | enrich countries on foo with x* = bar ",
            "Using wildcards (*) in ENRICH WITH projections is not allowed [x*]"