Address review comments

Author: bpintea

x-pack/plugin/esql-core/src/main/java/org/elasticsearch/xpack/esql/core/expression/FieldAttribute.java

@@ -243,14 +243,4 @@ protected String label() {
     public EsField field() {
         return field;
     }
-
-    /**
-     * If this field is unsupported this contains the underlying ES types. If there
-     * is a type conflict this will have many elements, some or all of which may
-     * be actually supported types.
-     */
-    @Nullable
-    public List<String> originalTypes() {
-        return null;
-    }
 }

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/UnsupportedAttribute.java

@@ -174,7 +174,10 @@ protected boolean innerEquals(Object o) {
         return super.innerEquals(other) && hasCustomMessage == other.hasCustomMessage && Objects.equals(message, other.message);
     }
 
-    @Override
+    /**
+     * This contains all the underlying ES types.
+     * On a type conflict this will have many elements, some or all of which may be actually supported types.
+     */
     public List<String> originalTypes() {
         return field().getOriginalTypes();
     }

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/plugin/TransportEsqlQueryAction.java

@@ -43,13 +43,13 @@
 import org.elasticsearch.xpack.esql.action.EsqlQueryResponse;
 import org.elasticsearch.xpack.esql.action.EsqlQueryTask;
 import org.elasticsearch.xpack.esql.core.async.AsyncTaskManagementService;
-import org.elasticsearch.xpack.esql.core.expression.FieldAttribute;
 import org.elasticsearch.xpack.esql.core.expression.FoldContext;
 import org.elasticsearch.xpack.esql.enrich.AbstractLookupService;
 import org.elasticsearch.xpack.esql.enrich.EnrichLookupService;
 import org.elasticsearch.xpack.esql.enrich.EnrichPolicyResolver;
 import org.elasticsearch.xpack.esql.enrich.LookupFromIndexService;
 import org.elasticsearch.xpack.esql.execution.PlanExecutor;
+import org.elasticsearch.xpack.esql.expression.function.UnsupportedAttribute;
 import org.elasticsearch.xpack.esql.inference.InferenceRunner;
 import org.elasticsearch.xpack.esql.session.Configuration;
 import org.elasticsearch.xpack.esql.session.EsqlSession.PlanRunner;
@@ -322,9 +322,9 @@ private EsqlExecutionInfo createEsqlExecutionInfo(EsqlQueryRequest request) {
     private EsqlQueryResponse toResponse(Task task, EsqlQueryRequest request, Configuration configuration, Result result) {
         List<ColumnInfoImpl> columns = result.schema().stream().map(c -> {
             List<String> originalTypes;
-            if (c instanceof FieldAttribute fa && (originalTypes = fa.originalTypes()) != null) {
+            if (c instanceof UnsupportedAttribute ua) {
                 // Sort the original types so they are easier to test against and prettier.
-                originalTypes = new ArrayList<>(originalTypes);
+                originalTypes = new ArrayList<>(ua.originalTypes());
                 Collections.sort(originalTypes);
             } else {
                 originalTypes = null;