1 files changed, 15 insertions, 10 deletions

diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index c8576722c69..273e996a6a0 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -564,6 +564,11 @@ Item *Item_sum::set_arg(uint i, THD *thd, Item *new_val)
 
 int Item_sum::set_aggregator(Aggregator::Aggregator_type aggregator)
 {
+  if (aggr)
+  {
+    DBUG_ASSERT(aggregator == aggr->Aggrtype());
+    return FALSE;
+  }
   switch (aggregator)
   {
   case Aggregator::DISTINCT_AGGREGATOR:
@@ -736,12 +741,12 @@ bool Aggregator_distinct::setup(THD *thd)
       if (list.push_back(item))
         return TRUE;                              // End of memory
       if (item->const_item() && item->is_null())
-        always_null=1;
+        always_null= true;
     }
     if (always_null)
       return FALSE;
-    count_field_types(select_lex,tmp_table_param,list,0);
-    tmp_table_param->force_copy_fields= item_sum->force_copy_fields;
+    count_field_types(select_lex, tmp_table_param, list, 0);
+    tmp_table_param->force_copy_fields= item_sum->has_force_copy_fields();
     DBUG_ASSERT(table == 0);
     /*
       Make create_tmp_table() convert BIT columns to BIGINT.
@@ -844,10 +849,10 @@ bool Aggregator_distinct::setup(THD *thd)
     List<Create_field> field_list;
     Create_field field_def;                              /* field definition */
     Item *arg;
-    DBUG_ENTER("Item_sum_distinct::setup");
+    DBUG_ENTER("Aggregator_distinct::setup");
     /* It's legal to call setup() more than once when in a subquery */
     if (tree)
-      return FALSE;
+      DBUG_RETURN(FALSE);
 
     /*
       Virtual table and the tree are created anew on each re-execution of
@@ -855,23 +860,23 @@ bool Aggregator_distinct::setup(THD *thd)
       mem_root.
     */
     if (field_list.push_back(&field_def))
-      return TRUE;
+      DBUG_RETURN(TRUE);
 
     item_sum->null_value= item_sum->maybe_null= 1;
     item_sum->quick_group= 0;
 
     DBUG_ASSERT(item_sum->get_arg(0)->fixed);
 
-    arg = item_sum->get_arg(0);
+    arg= item_sum->get_arg(0);
     if (arg->const_item())
     {
       (void) arg->val_int();
       if (arg->null_value)
-        always_null=1;
+        always_null= true;
     }
 
     if (always_null)
-      return FALSE;
+      DBUG_RETURN(FALSE);
 
     enum enum_field_types field_type;
 
@@ -884,7 +889,7 @@ bool Aggregator_distinct::setup(THD *thd)
                                  arg->unsigned_flag);
 
     if (! (table= create_virtual_tmp_table(thd, field_list)))
-      return TRUE;
+      DBUG_RETURN(TRUE);
 
     /* XXX: check that the case of CHAR(0) works OK */
     tree_key_length= table->s->reclength - table->s->null_bytes;