disable agg function in unwind clause

src/graph/validator/MatchValidator.cpp

@@ -503,6 +503,10 @@ Status MatchValidator::validateUnwind(const UnwindClause *unwindClause,
   }
   unwindCtx.alias = unwindClause->alias();
   unwindCtx.unwindExpr = unwindClause->expr()->clone();
+  if (ExpressionUtils::hasAny(unwindCtx.unwindExpr, {Expression::Kind::kAggregate})) {
+    return Status::SemanticError("Can't use aggregating expressions in unwind clause, `%s'",
+                                 unwindCtx.unwindExpr->toString().c_str());
+  }
 
   auto labelExprs = ExpressionUtils::collectAll(unwindCtx.unwindExpr, {Expression::Kind::kLabel});
   for (auto *labelExpr : labelExprs) {

tests/tck/features/match/Unwind.feature

@@ -131,3 +131,26 @@ Feature: Unwind clause
       | <("Tim Duncan" :bachelor{name: "Tim Duncan", speciality: "psychology"} :player{age: 42, name: "Tim Duncan"})-[:like@0 {likeness: 95}]->("Manu Ginobili" :player{age: 41, name: "Manu Ginobili"})>                                                                                         |
       | <("Tim Duncan" :bachelor{name: "Tim Duncan", speciality: "psychology"} :player{age: 42, name: "Tim Duncan"})-[:like@0 {likeness: 95}]->("Tony Parker" :player{age: 36, name: "Tony Parker"})-[:like@0 {likeness: 95}]->("Manu Ginobili" :player{age: 41, name: "Manu Ginobili"})>         |
       | <("Tim Duncan" :bachelor{name: "Tim Duncan", speciality: "psychology"} :player{age: 42, name: "Tim Duncan"})-[:like@0 {likeness: 95}]->("Tony Parker" :player{age: 36, name: "Tony Parker"})-[:like@0 {likeness: 90}]->("LaMarcus Aldridge" :player{age: 33, name: "LaMarcus Aldridge"})> |
+
+  Scenario: unwind invalid expression
+    When executing query:
+      """
+      UNWIND collect([1,2,3]) as n return n
+      """
+    Then a SemanticError should be raised at runtime: Can't use aggregating expressions in unwind clause, `collect([1,2,3])'
+    When executing query:
+      """
+      LOOKUP on player YIELD id(vertex) as id |
+      GO 1 TO 3 STEPS FROM $-.id OVER * BIDIRECT YIELD DISTINCT src(edge) as src_id, dst(edge) as dst_id |
+      UNWIND collect($-.src_id) + collect($-.dst_id) as vid
+      WITH DISTINCT vid
+      RETURN collect(vid) as vids
+      """
+    Then a SemanticError should be raised at runtime: Can't use aggregating expressions in unwind clause, `(collect($-.src_id)+collect($-.dst_id))'
+    When executing query:
+      """
+      MATCH (a:player {name:"Tim Duncan"}) - [e:like] -> (b)
+      UNWIND count(b) as num
+      RETURN  num
+      """
+    Then a SemanticError should be raised at runtime: Can't use aggregating expressions in unwind clause, `count(b)'