diff --git a/extra/mariabackup/encryption_plugin.cc b/extra/mariabackup/encryption_plugin.cc
index ab87ce0b7bd..04e8ae83957 100644
--- a/extra/mariabackup/encryption_plugin.cc
+++ b/extra/mariabackup/encryption_plugin.cc
@@ -194,7 +194,7 @@ const char *encryption_plugin_get_config()
   return encryption_plugin_config.c_str();
 }
 
-extern int finalize_encryption_plugin(st_plugin_int *plugin);
+extern int finalize_encryption_plugin(void *plugin);
 
 
 void encryption_plugin_prepare_init(int argc, char **argv)
diff --git a/sql/encryption.cc b/sql/encryption.cc
index 13239b91910..79939cdc012 100644
--- a/sql/encryption.cc
+++ b/sql/encryption.cc
@@ -59,8 +59,9 @@ uint ctx_size(unsigned int, unsigned int)
 
 } /* extern "C" */
 
-int initialize_encryption_plugin(st_plugin_int *plugin)
+int initialize_encryption_plugin(void *plugin_)
 {
+  st_plugin_int *plugin= static_cast<st_plugin_int *>(plugin_);
   if (encryption_manager)
     return 1;
 
@@ -107,8 +108,9 @@ int initialize_encryption_plugin(st_plugin_int *plugin)
   return 0;
 }
 
-int finalize_encryption_plugin(st_plugin_int *plugin)
+int finalize_encryption_plugin(void *plugin_)
 {
+  st_plugin_int *plugin= static_cast<st_plugin_int *>(plugin_);
   bool used= plugin_ref_to_int(encryption_manager) == plugin;
 
   if (used)
diff --git a/sql/handler.cc b/sql/handler.cc
index 10ea7da1088..4ecd1ea2048 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -566,8 +566,9 @@ static int hton_drop_table(handlerton *hton, const char *path)
 }
 
 
-int ha_finalize_handlerton(st_plugin_int *plugin)
+int ha_finalize_handlerton(void *plugin_)
 {
+  st_plugin_int *plugin= static_cast<st_plugin_int *>(plugin_);
   handlerton *hton= (handlerton *)plugin->data;
   DBUG_ENTER("ha_finalize_handlerton");
 
@@ -618,8 +619,9 @@ int ha_finalize_handlerton(st_plugin_int *plugin)
 }
 
 
-int ha_initialize_handlerton(st_plugin_int *plugin)
+int ha_initialize_handlerton(void *plugin_)
 {
+  st_plugin_int *plugin= static_cast<st_plugin_int *>(plugin_);
   handlerton *hton;
   static const char *no_exts[]= { 0 };
   int ret= 0;
diff --git a/sql/handler.h b/sql/handler.h
index ac97a41a4f1..fc3d00d43d5 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -5101,8 +5101,8 @@ static inline bool ha_storage_engine_is_enabled(const handlerton *db_type)
 int ha_init_errors(void);
 int ha_init(void);
 int ha_end(void);
-int ha_initialize_handlerton(st_plugin_int *plugin);
-int ha_finalize_handlerton(st_plugin_int *plugin);
+int ha_initialize_handlerton(void *plugin);
+int ha_finalize_handlerton(void *plugin);
 
 TYPELIB *ha_known_exts(void);
 int ha_panic(enum ha_panic_function flag);
diff --git a/sql/sql_audit.cc b/sql/sql_audit.cc
index 6ee6ede31b8..6f0d3afbff7 100644
--- a/sql/sql_audit.cc
+++ b/sql/sql_audit.cc
@@ -18,8 +18,8 @@
 #include "mysqld.h"
 #include "sql_audit.h"
 
-extern int initialize_audit_plugin(st_plugin_int *plugin);
-extern int finalize_audit_plugin(st_plugin_int *plugin);
+extern int initialize_audit_plugin(void *plugin);
+extern int finalize_audit_plugin(void *plugin);
 
 #ifndef EMBEDDED_LIBRARY
 
@@ -262,8 +262,9 @@ void mysql_audit_finalize()
   @retval TRUE   There was an error.
 */
 
-int initialize_audit_plugin(st_plugin_int *plugin)
+int initialize_audit_plugin(void *plugin_)
 {
+  st_plugin_int *plugin= static_cast<st_plugin_int *>(plugin_);
   st_mysql_audit *data= (st_mysql_audit*) plugin->plugin->info;
 
   if (!data->event_notify || !data->class_mask[0])
@@ -346,8 +347,9 @@ static my_bool calc_class_mask(THD *thd, plugin_ref plugin, void *arg)
   @retval FALSE  OK
   @retval TRUE   There was an error.
 */
-int finalize_audit_plugin(st_plugin_int *plugin)
+int finalize_audit_plugin(void *plugin_)
 {
+  st_plugin_int *plugin= static_cast<st_plugin_int *>(plugin_);
   unsigned long event_class_mask[MYSQL_AUDIT_CLASS_MASK_SIZE];
   
   if (plugin->plugin->deinit && plugin->plugin->deinit(NULL))
@@ -458,13 +460,13 @@ void mysql_audit_finalize()
 }
 
 
-int initialize_audit_plugin(st_plugin_int *plugin)
+int initialize_audit_plugin(void *plugin)
 {
   return 1;
 }
 
 
-int finalize_audit_plugin(st_plugin_int *plugin)
+int finalize_audit_plugin(void *plugin)
 {
   return 0;
 }
diff --git a/sql/sql_plugin.cc b/sql/sql_plugin.cc
index 624a4fa2e9b..56c7b3332a2 100644
--- a/sql/sql_plugin.cc
+++ b/sql/sql_plugin.cc
@@ -103,16 +103,16 @@ const LEX_CSTRING plugin_type_names[MYSQL_MAX_PLUGIN_TYPE_NUM]=
   { STRING_WITH_LEN("FUNCTION") }
 };
 
-extern int initialize_schema_table(st_plugin_int *plugin);
-extern int finalize_schema_table(st_plugin_int *plugin);
+extern int initialize_schema_table(void *plugin);
+extern int finalize_schema_table(void *plugin);
 
-extern int initialize_audit_plugin(st_plugin_int *plugin);
-extern int finalize_audit_plugin(st_plugin_int *plugin);
+extern int initialize_audit_plugin(void *plugin);
+extern int finalize_audit_plugin(void *plugin);
 
-extern int initialize_encryption_plugin(st_plugin_int *plugin);
-extern int finalize_encryption_plugin(st_plugin_int *plugin);
+extern int initialize_encryption_plugin(void *plugin);
+extern int finalize_encryption_plugin(void *plugin);
 
-extern int initialize_data_type_plugin(st_plugin_int *plugin);
+extern int initialize_data_type_plugin(void *plugin);
 
 /*
   The number of elements in both plugin_type_initialize and
@@ -1446,8 +1446,9 @@ static int plugin_do_initialize(struct st_plugin_int *plugin, uint &state)
   mysql_mutex_assert_not_owner(&LOCK_plugin);
   plugin_type_init init= plugin_type_initialize[plugin->plugin->type];
   if (!init)
-    init= (plugin_type_init) plugin->plugin->init;
+    init= plugin->plugin->init;
   if (init)
+  {
     if (int ret= init(plugin))
     {
       /* Plugin init failed and did not requested a retry */
@@ -1455,6 +1456,7 @@ static int plugin_do_initialize(struct st_plugin_int *plugin, uint &state)
         print_init_failed_error(plugin);
       DBUG_RETURN(ret);
     }
+  }
   state= PLUGIN_IS_READY; // plugin->init() succeeded
 
   if (plugin->plugin->status_vars)
diff --git a/sql/sql_plugin.h b/sql/sql_plugin.h
index eaf0b40f34a..5e62f2a5e45 100644
--- a/sql/sql_plugin.h
+++ b/sql/sql_plugin.h
@@ -152,7 +152,7 @@ typedef struct st_plugin_int **plugin_ref;
 #define plugin_equals(p1,p2) ((p1) && (p2) && (p1)[0] == (p2)[0])
 #endif
 
-typedef int (*plugin_type_init)(struct st_plugin_int *);
+typedef int (*plugin_type_init)(void *);
 
 extern I_List<i_string> *opt_plugin_load_list_ptr;
 extern char *opt_plugin_dir_ptr;
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index aafaf3b6a41..2965cdf0199 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -9938,8 +9938,9 @@ ST_SCHEMA_TABLE schema_tables[]=
 };
 
 
-int initialize_schema_table(st_plugin_int *plugin)
+int initialize_schema_table(void *plugin_)
 {
+  st_plugin_int *plugin= static_cast<st_plugin_int *>(plugin_);
   ST_SCHEMA_TABLE *schema_table;
   int err;
   DBUG_ENTER("initialize_schema_table");
@@ -9984,9 +9985,10 @@ int initialize_schema_table(st_plugin_int *plugin)
   DBUG_RETURN(0);
 }
 
-int finalize_schema_table(st_plugin_int *plugin)
+int finalize_schema_table(void *plugin_)
 {
-  ST_SCHEMA_TABLE *schema_table= (ST_SCHEMA_TABLE *)plugin->data;
+  st_plugin_int *plugin= static_cast<st_plugin_int *>(plugin_);
+  ST_SCHEMA_TABLE *schema_table= static_cast<ST_SCHEMA_TABLE *>(plugin->data);
   DBUG_ENTER("finalize_schema_table");
 
   if (schema_table)
diff --git a/sql/sql_type.cc b/sql/sql_type.cc
index e46a3f2fda4..114c5ab9786 100644
--- a/sql/sql_type.cc
+++ b/sql/sql_type.cc
@@ -9566,9 +9566,11 @@ Charset::eq_collation_specific_names(CHARSET_INFO *cs) const
   return name0.length && !cmp(&name0, &name1);
 }
 
-int initialize_data_type_plugin(st_plugin_int *plugin)
+int initialize_data_type_plugin(void *plugin_)
 {
-  st_mariadb_data_type *data= (st_mariadb_data_type*) plugin->plugin->info;
+  st_plugin_int *plugin= static_cast<st_plugin_int *>(plugin_);
+  st_mariadb_data_type *data=
+      static_cast<st_mariadb_data_type *>(plugin->plugin->info);
   data->type_handler->set_name(Name(plugin->name));
   if (plugin->plugin->init && plugin->plugin->init(NULL))
   {