### Description

`FROM test | eval x1 = pow(emp_no, 1), x2 = pow(x1, 1), x3 = pow(x2, 2)`

or

`FROM test | eval x1 = substring(ip1, 3), x2 = substring(x1, 2), x3 = substring(x2, 2)`

or

`FROM test | eval x1 = concat(ip1, ip2), x2 = concat(x1, "--"), x3 = concat(x2, "**")`

will fail with 

```
                "type": "verification_exception",
                "reason": "Found 1 problem\nline 1:65: Unknown column [x2], did you mean [x1]?"
```

Spawned from https://github.com/elastic/elasticsearch/issues/99472
x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/analysis/AnalyzerTests.java
| keep unsigned_long, date, date_nanos, unsupported, point, version
            """, "mapping-multi-field-variation.json", "unsigned_long", "date", "date_nanos", "unsupported", "point", "version");
    }
    public void testUnsupportedDottedFieldUsedExplicitly() {
        assertProjectionWithMapping("""
            from test
            | keep some.string
            """, "mapping-multi-field-variation.json", "some.string");
    }
    public void testUnsupportedParentField() {
        verifyUnsupported(
            """
                from test
                | keep text, text.keyword
                """,
            "Found 1 problem\n" + "line 2:14: Unknown column [text.keyword], did you mean any of [text.wildcard, text.raw]?",
            "mapping-multi-field.json"
        );
    }
    public void testUnsupportedParentFieldAndItsSubField() {
        assertProjectionWithMapping("""
            from test
            | keep text, text.english
            """, "mapping-multi-field.json", "text", "text.english");
    }
    public void testUnsupportedDeepHierarchy() {
        assertProjectionWithMapping("""
            from test
            | keep x.y.z.w, x.y.z, x.y, x
            """, "mapping-multi-field-with-nested.json", "x.y.z.w", "x.y.z", "x.y", "x");