Fix gcc 7.3 compiler warnings.

sql/opt_range.cc

@@ -7307,7 +7307,8 @@ SEL_TREE *Item_bool_func::get_full_func_mm_tree(RANGE_OPT_PARAM *param,
 		          param->current_table);
 #ifdef HAVE_SPATIAL
   Field::geometry_type sav_geom_type;
-  if (field_item->field->type() == MYSQL_TYPE_GEOMETRY)
+  const bool geometry= field_item->field->type() == MYSQL_TYPE_GEOMETRY;
+  if (geometry)
   {
     sav_geom_type= ((Field_geom*) field_item->field)->geom_type;
     /* We have to be able to store all sorts of spatial features here */
@@ -7342,7 +7343,7 @@ SEL_TREE *Item_bool_func::get_full_func_mm_tree(RANGE_OPT_PARAM *param,
   }
 
 #ifdef HAVE_SPATIAL
-  if (field_item->field->type() == MYSQL_TYPE_GEOMETRY)
+  if (geometry)
   {
     ((Field_geom*) field_item->field)->geom_type= sav_geom_type;
   }

sql/opt_subselect.cc

@@ -2776,8 +2776,8 @@ void advance_sj_state(JOIN *join, table_map remaining_tables, uint idx,
     LooseScan detector in best_access_path)
   */
   remaining_tables &= ~new_join_tab->table->map;
-  table_map dups_producing_tables, prev_dups_producing_tables,
-            prev_sjm_lookup_tables;
+  table_map dups_producing_tables, prev_dups_producing_tables= 0,
+            prev_sjm_lookup_tables= 0;
 
   if (idx == join->const_tables)
     dups_producing_tables= 0;
@@ -2788,7 +2788,7 @@ void advance_sj_state(JOIN *join, table_map remaining_tables, uint idx,
   if ((emb_sj_nest= new_join_tab->emb_sj_nest))
     dups_producing_tables |= emb_sj_nest->sj_inner_tables;
 
-  Semi_join_strategy_picker **strategy, **prev_strategy;
+  Semi_join_strategy_picker **strategy, **prev_strategy= NULL;
   if (idx == join->const_tables)
   {
     /* First table, initialize pickers */

sql/sql_acl.cc

@@ -2891,7 +2891,8 @@ int acl_set_default_role(THD *thd, const char *host, const char *user,
   ulong query_length= 0;
   bool clear_role= FALSE;
   char buff[512];
-  enum_binlog_format save_binlog_format;
+  enum_binlog_format save_binlog_format=
+    thd->get_current_stmt_binlog_format();
   const CSET_STRING query_save __attribute__((unused)) = thd->query_string;
 
   DBUG_ENTER("acl_set_default_role");
@@ -2922,6 +2923,7 @@ int acl_set_default_role(THD *thd, const char *host, const char *user,
   if (WSREP(thd) && !IF_WSREP(thd->wsrep_applier, 0))
   {
     thd->set_query(buff, query_length, system_charset_info);
+    // Attention!!! here is implicit goto error;
     WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, (char*)"user", NULL);
   }
 

sql/sql_class.h

@@ -3562,6 +3562,10 @@ class THD :public Statement,
     *format= (enum_binlog_format) variables.binlog_format;
     *current_format= current_stmt_binlog_format;
   }
+  inline enum_binlog_format get_current_stmt_binlog_format()
+  {
+    return current_stmt_binlog_format;
+  }
   inline void set_binlog_format(enum_binlog_format format,
                                 enum_binlog_format current_format)
   {

sql/sql_explain.cc

@@ -895,7 +895,7 @@ void Explain_select::print_explain_json(Explain_query *query,
       {
         Sort_and_group_tracker::Iterator iter(&ops_tracker);
         enum_qep_action action;
-        Filesort_tracker *fs_tracker;
+        Filesort_tracker *fs_tracker= NULL;
 
         while ((action= iter.get_next(&fs_tracker)) != EXPL_ACTION_EOF)
         {

sql/sql_partition.cc

@@ -8313,6 +8313,12 @@ int create_partition_name(char *out, size_t outlen, const char *in1,
     end= strxnmov(out, outlen-1, in1, "#P#", transl_part, "#TMP#", NullS);
   else if (name_variant == RENAMED_PART_NAME)
     end= strxnmov(out, outlen-1, in1, "#P#", transl_part, "#REN#", NullS);
+  else
+  {
+    DBUG_ASSERT(0);
+    out[0]= 0;
+    end= out + (outlen-1);
+  }
   if (end - out == static_cast<ptrdiff_t>(outlen-1))
   {
     my_error(ER_PATH_LENGTH, MYF(0), longest_str(in1, transl_part));
@@ -8355,6 +8361,12 @@ int create_subpartition_name(char *out, size_t outlen,
   else if (name_variant == RENAMED_PART_NAME)
     end= strxnmov(out, outlen-1, in1, "#P#", transl_part_name,
                   "#SP#", transl_subpart_name, "#REN#", NullS);
+  else
+  {
+    DBUG_ASSERT(0);
+    out[0]= 0;
+    end= out + (outlen-1);
+  }
   if (end - out == static_cast<ptrdiff_t>(outlen-1))
   {
     my_error(ER_PATH_LENGTH, MYF(0),

sql/table.cc

@@ -1723,7 +1723,7 @@ int TABLE_SHARE::init_from_binary_frm_image(THD *thd, bool write,
     keyinfo= share->key_info;
     uint primary_key= my_strcasecmp(system_charset_info, share->keynames.type_names[0],
                                     primary_key_name) ? MAX_KEY : 0;
-    KEY* key_first_info;
+    KEY* key_first_info= NULL;
 
     if (primary_key >= MAX_KEY && keyinfo->flags & HA_NOSAME)
     {