Moving fix_length_and_dec() from Item_result_field to Item_func_or_sum,

as the other decendants of Item_result_field (Item_avg_field,
Item_variance_field, Item_cache_wrapper) don't need fix_length_and_dec().

sql/item.h

@@ -3254,7 +3254,6 @@ public:
   Field *get_tmp_table_field() { return result_field; }
   Field *tmp_table_field(TABLE *t_arg) { return result_field; }
   table_map used_tables() const { return 1; }
-  virtual void fix_length_and_dec()=0;
   void set_result_field(Field *field) { result_field= field; }
   bool is_result_field() { return 1; }
   void save_in_result_field(bool no_conversions)
@@ -3367,6 +3366,7 @@ public:
     also to make printing of items inherited from Item_sum uniform.
   */
   virtual const char *func_name() const= 0;
+  virtual void fix_length_and_dec()= 0;
 };
 
 
@@ -3652,7 +3652,6 @@ public:
   bool set_cache(THD *thd);
 
   bool fix_fields(THD *thd, Item **it);
-  void fix_length_and_dec() {}
   void cleanup();
 
   /* Methods of getting value which should be cached in the cache */

sql/item_func.cc

@@ -3482,7 +3482,7 @@ void udf_handler::cleanup()
 
 
 bool
-udf_handler::fix_fields(THD *thd, Item_result_field *func,
+udf_handler::fix_fields(THD *thd, Item_func_or_sum *func,
 			uint arg_count, Item **arguments)
 {
   uchar buff[STACK_BUFF_ALLOC];			// Max argument in function

sql/item_sum.h

@@ -829,7 +829,6 @@ public:
     return hybrid_type == DECIMAL_RESULT ?
       MYSQL_TYPE_NEWDECIMAL : MYSQL_TYPE_DOUBLE;
   }
-  void fix_length_and_dec() {}
   enum Item_result result_type () const { return hybrid_type; }
   bool check_vcol_func_processor(uchar *int_arg) 
   {
@@ -909,7 +908,6 @@ public:
     return hybrid_type == DECIMAL_RESULT ?
       MYSQL_TYPE_NEWDECIMAL : MYSQL_TYPE_DOUBLE;
   }
-  void fix_length_and_dec() {}
   enum Item_result result_type () const { return hybrid_type; }
   bool check_vcol_func_processor(uchar *int_arg) 
   {

sql/sql_udf.h

@@ -76,7 +76,7 @@ class udf_handler :public Sql_alloc
   Item_result result_type () const
   { return u_d	? u_d->returns : STRING_RESULT;}
   bool get_arguments();
-  bool fix_fields(THD *thd, Item_result_field *item,
+  bool fix_fields(THD *thd, Item_func_or_sum *item,
 		  uint arg_count, Item **args);
   void cleanup();
   double val(my_bool *null_value)