Adding the `override` keyword into all classes in the Type_handler hierarchy, for consistency.

sql/sql_type_geom.h

@@ -346,9 +346,12 @@ class Field_geom :public Field_blob
   { srid= field_srid; }
   enum_conv_type rpl_conv_type_from(const Conv_source &source,
                                     const Relay_log_info *rli,
-                                    const Conv_param &param) const;
-  enum ha_base_keytype key_type() const { return HA_KEYTYPE_VARBINARY2; }
-  const Type_handler *type_handler() const
+                                    const Conv_param &param) const override;
+  enum ha_base_keytype key_type() const  override
+  {
+    return HA_KEYTYPE_VARBINARY2;
+  }
+  const Type_handler *type_handler() const override
   {
     return m_type_handler;
   }
@@ -360,28 +363,28 @@ class Field_geom :public Field_blob
   {
     m_type_handler= th;
   }
-  enum_field_types type() const
+  enum_field_types type() const override
   {
     return MYSQL_TYPE_GEOMETRY;
   }
-  enum_field_types real_type() const
+  enum_field_types real_type() const override
   {
     return MYSQL_TYPE_GEOMETRY;
   }
   Information_schema_character_attributes
-    information_schema_character_attributes() const
+    information_schema_character_attributes() const override
   {
     return Information_schema_character_attributes();
   }
-  void make_send_field(Send_field *to)
+  void make_send_field(Send_field *to) override
   {
     Field_longstr::make_send_field(to);
   }
   bool can_optimize_range(const Item_bool_func *cond,
                                   const Item *item,
-                                  bool is_eq_func) const;
-  void sql_type(String &str) const;
-  Copy_func *get_copy_func(const Field *from) const
+                                  bool is_eq_func) const override;
+  void sql_type(String &str) const override;
+  Copy_func *get_copy_func(const Field *from) const override
   {
     const Type_handler_geometry *fth=
       dynamic_cast<const Type_handler_geometry*>(from->type_handler());
@@ -389,7 +392,7 @@ class Field_geom :public Field_blob
       return get_identical_copy_func();
     return do_conv_blob;
   }
-  bool memcpy_field_possible(const Field *from) const
+  bool memcpy_field_possible(const Field *from) const override
   {
     const Type_handler_geometry *fth=
       dynamic_cast<const Type_handler_geometry*>(from->type_handler());
@@ -397,17 +400,18 @@ class Field_geom :public Field_blob
            m_type_handler->is_binary_compatible_geom_super_type_for(fth) &&
            !table->copy_blobs;
   }
-  bool is_equal(const Column_definition &new_field) const;
-  bool can_be_converted_by_engine(const Column_definition &new_type) const
+  bool is_equal(const Column_definition &new_field) const override;
+  bool can_be_converted_by_engine(const Column_definition &new_type)
+                                  const override
   {
     return false; // Override the Field_blob behavior
   }
 
-  int  store(const char *to, size_t length, CHARSET_INFO *charset);
-  int  store(double nr);
-  int  store(longlong nr, bool unsigned_val);
-  int  store_decimal(const my_decimal *);
-  uint size_of() const { return sizeof(*this); }
+  int  store(const char *to, size_t length, CHARSET_INFO *charset) override;
+  int  store(double nr) override;
+  int  store(longlong nr, bool unsigned_val) override;
+  int  store_decimal(const my_decimal *) override;
+  uint size_of() const  override{ return sizeof(*this); }
   /**
    Key length is provided only to support hash joins. (compared byte for byte)
    Ex: SELECT .. FROM t1,t2 WHERE t1.field_geom1=t2.field_geom2.
@@ -415,19 +419,19 @@ class Field_geom :public Field_blob
    The comparison is not very relevant, as identical geometry might be
    represented differently, but we need to support it either way.
   */
-  uint32 key_length() const { return packlength; }
-  uint get_key_image(uchar *buff,uint length, imagetype type_arg);
+  uint32 key_length() const  override{ return packlength; }
+  uint get_key_image(uchar *buff,uint length, imagetype type_arg) override;
 
   /**
     Non-nullable GEOMETRY types cannot have defaults,
     but the underlying blob must still be reset.
    */
-  int reset(void) { return Field_blob::reset() || !maybe_null(); }
-  bool load_data_set_null(THD *thd);
-  bool load_data_set_no_data(THD *thd, bool fixed_format);
+  int reset(void)  override{ return Field_blob::reset() || !maybe_null(); }
+  bool load_data_set_null(THD *thd) override;
+  bool load_data_set_no_data(THD *thd, bool fixed_format) override;
 
   uint get_srid() const { return srid; }
-  void print_key_value(String *out, uint32 length)
+  void print_key_value(String *out, uint32 length) override
   {
     out->append(STRING_WITH_LEN("unprintable_geometry_value"));
   }