[Fix](Lateral View) The Error expr type when exploding a function res…

…ult of inline view (apache#8851)

Fixed apache#8850

The column in inline view maybe a function instead of slotRef.
So when this column is used as the input of explode function,
it can't be converted to slotRef.

The correct way is to treat it as an Expr and extract the required slotRef for materialization.
For example:
```
with d as (select k1+k1 as k1_plus from table)
select k1_plus from d explode_split(k1_plus, ",")
```
FnExp: SlorRef<k1_plus>
SubstituteFnExpr: functionCallExpr<k1+k1>
originSlotRefList: SlotRef<k1>

fe/fe-core/src/main/java/org/apache/doris/analysis/LateralViewRef.java

@@ -26,7 +26,6 @@
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Lists;
 
-import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -42,7 +41,7 @@ public class LateralViewRef extends TableRef {
 
     // after analyzed
     private FunctionCallExpr fnExpr;
-    private ArrayList<Expr> originSlotRefList = Lists.newArrayList();
+    private List<SlotRef> originSlotRefList = Lists.newArrayList();
     private InlineView view;
     private SlotRef explodeSlotRef;
 
@@ -98,7 +97,6 @@ private void analyzeFunctionExpr(Analyzer analyzer) throws AnalysisException {
         for (Expr expr : fnExpr.getChildren()) {
             checkScalarFunction(expr);
         }
-        fnExpr.collect(SlotRef.class, originSlotRefList);
     }
 
     @Override
@@ -116,11 +114,13 @@ public TupleDescriptor createTupleDescriptor(Analyzer analyzer) throws AnalysisE
     }
 
     public void materializeRequiredSlots(ExprSubstitutionMap baseTblSmap, Analyzer analyzer) throws AnalysisException {
+        Expr substituteFnExpr = fnExpr;
         if (relatedTableRef instanceof InlineViewRef) {
-            originSlotRefList = Expr.trySubstituteList(originSlotRefList, baseTblSmap, analyzer, false);
+            substituteFnExpr = fnExpr.trySubstitute(baseTblSmap, analyzer, false);
         }
-        for (Expr originSlotRef : originSlotRefList) {
-            ((SlotRef) originSlotRef).getDesc().setIsMaterialized(true);
+        substituteFnExpr.collect(SlotRef.class, originSlotRefList);
+        for (SlotRef originSlotRef : originSlotRefList) {
+            originSlotRef.getDesc().setIsMaterialized(true);
         }
         explodeSlotRef.getDesc().setIsMaterialized(true);
     }

fe/fe-core/src/test/java/org/apache/doris/planner/TableFunctionPlanTest.java

@@ -527,4 +527,15 @@ public void testLateralViewUnknownColumnBug() throws Exception {
         String explainString = UtFrameUtils.getSQLPlanOrErrorMsg(ctx, sql, true);
         Assert.assertTrue(!explainString.contains("Unknown column 'e1' in 'table list'"));
     }
+
+
+    // The 'k1' column in 'd' view should be materialized
+    // Fix #8850
+    @Test
+    public void testLateralViewWithInlineViewBug() throws Exception {
+        String sql = "with d as (select k1+k1 as k1 from db1.table_for_view ) "
+                + "select k1 from d lateral view explode_split(k1,',') tmp as e1;";
+        String explainString = UtFrameUtils.getSQLPlanOrErrorMsg(ctx, sql, true);
+        Assert.assertTrue(!explainString.contains("Unexpected exception: org.apache.doris.analysis.FunctionCallExpr cannot be cast to org.apache.doris.analysis.SlotRef"));
+    }
 }