diff --git a/include/mysql/plugin_audit.h.pp b/include/mysql/plugin_audit.h.pp
index 4ede09a0d41..e13acc715d4 100644
--- a/include/mysql/plugin_audit.h.pp
+++ b/include/mysql/plugin_audit.h.pp
@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);
diff --git a/include/mysql/plugin_auth.h.pp b/include/mysql/plugin_auth.h.pp
index ab32177fbb0..442eeb9c048 100644
--- a/include/mysql/plugin_auth.h.pp
+++ b/include/mysql/plugin_auth.h.pp
@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);
diff --git a/include/mysql/plugin_data_type.h.pp b/include/mysql/plugin_data_type.h.pp
index 34b8dadd75e..5d5812e50fc 100644
--- a/include/mysql/plugin_data_type.h.pp
+++ b/include/mysql/plugin_data_type.h.pp
@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);
diff --git a/include/mysql/plugin_encryption.h.pp b/include/mysql/plugin_encryption.h.pp
index 449ee46d585..fc6c8a708c1 100644
--- a/include/mysql/plugin_encryption.h.pp
+++ b/include/mysql/plugin_encryption.h.pp
@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);
diff --git a/include/mysql/plugin_ftparser.h.pp b/include/mysql/plugin_ftparser.h.pp
index 42c3e093150..85c73919bfd 100644
--- a/include/mysql/plugin_ftparser.h.pp
+++ b/include/mysql/plugin_ftparser.h.pp
@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);
diff --git a/include/mysql/plugin_function.h.pp b/include/mysql/plugin_function.h.pp
index 2e78d23ae2e..1abb2f47ede 100644
--- a/include/mysql/plugin_function.h.pp
+++ b/include/mysql/plugin_function.h.pp
@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);
diff --git a/include/mysql/plugin_password_validation.h.pp b/include/mysql/plugin_password_validation.h.pp
index 138422e2b3e..1284a3b0135 100644
--- a/include/mysql/plugin_password_validation.h.pp
+++ b/include/mysql/plugin_password_validation.h.pp
@@ -301,18 +301,22 @@ void my_sha512_input(void *context, const unsigned char *buf, size_t len);
 void my_sha512_result(void *context, unsigned char *digest);
 }
 extern "C" {
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 struct st_mysql_const_lex_string
 {
   const char *str;
   size_t length;
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const THD*, size_t);
   void *(*thd_calloc_func)(const THD*, size_t);
diff --git a/include/mysql/service_thd_alloc.h b/include/mysql/service_thd_alloc.h
index e85a8e8c4e0..014277b5d00 100644
--- a/include/mysql/service_thd_alloc.h
+++ b/include/mysql/service_thd_alloc.h
@@ -35,13 +35,6 @@
 extern "C" {
 #endif
 
-struct st_mysql_lex_string
-{
-  char *str;
-  size_t length;
-};
-typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
-
 struct st_mysql_const_lex_string
 {
   const char *str;
@@ -49,6 +42,20 @@ struct st_mysql_const_lex_string
 };
 typedef struct st_mysql_const_lex_string MYSQL_CONST_LEX_STRING;
 
+struct st_mysql_lex_string
+{
+  char *str;
+  size_t length;
+#ifdef __cplusplus
+  // Allow automatic cast from LEX_STRING to LEX_CSTRING in c++.
+  operator struct st_mysql_const_lex_string() const
+  {
+    return {str, length};
+  }
+#endif
+};
+typedef struct st_mysql_lex_string MYSQL_LEX_STRING;
+
 extern struct thd_alloc_service_st {
   void *(*thd_alloc_func)(const MYSQL_THD, size_t);
   void *(*thd_calloc_func)(const MYSQL_THD, size_t);
diff --git a/plugin/metadata_lock_info/metadata_lock_info.cc b/plugin/metadata_lock_info/metadata_lock_info.cc
index a85048de47f..35b9b507513 100644
--- a/plugin/metadata_lock_info/metadata_lock_info.cc
+++ b/plugin/metadata_lock_info/metadata_lock_info.cc
@@ -70,7 +70,7 @@ int i_s_metadata_lock_info_fill_row(
     DBUG_RETURN(0);
   table->field[0]->store((longlong) mdl_ctx->get_thread_id(), TRUE);
   table->field[1]->set_notnull();
-  table->field[1]->store(mdl_ticket->get_type_name(), system_charset_info);
+  table->field[1]->store(*mdl_ticket->get_type_name(), system_charset_info);
   table->field[2]->set_null();
   table->field[3]->set_notnull();
   table->field[3]->store(
diff --git a/sql/field.h b/sql/field.h
index edf6cc3400f..ed7ded2f5c1 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -981,11 +981,6 @@ public:
             enum_check_fields check_level);
   int store_text(const char *to, size_t length, CHARSET_INFO *cs,
                  enum_check_fields check_level);
-  int store(const LEX_STRING *ls, CHARSET_INFO *cs)
-  {
-    DBUG_ASSERT(ls->length < UINT_MAX32);
-    return store(ls->str, (uint) ls->length, cs);
-  }
   int store(const LEX_CSTRING *ls, CHARSET_INFO *cs)
   {
     DBUG_ASSERT(ls->length < UINT_MAX32);
diff --git a/sql/sp_instr.h b/sql/sp_instr.h
index 8a7ad48d145..f71030eadfe 100644
--- a/sql/sp_instr.h
+++ b/sql/sp_instr.h
@@ -514,7 +514,7 @@ public:
 protected:
   LEX_CSTRING get_expr_query() const override
   {
-    return LEX_CSTRING{m_query.str, m_query.length};
+    return m_query;
   }
 
   bool on_after_expr_parsing(THD *) override
diff --git a/sql/sql_cmd.h b/sql/sql_cmd.h
index 985be776713..bedd7e118f0 100644
--- a/sql/sql_cmd.h
+++ b/sql/sql_cmd.h
@@ -133,11 +133,6 @@ public:
   Storage_engine_name(const LEX_CSTRING &name)
    :m_storage_engine_name(name)
   { }
-  Storage_engine_name(const LEX_STRING &name)
-  {
-    m_storage_engine_name.str= name.str;
-    m_storage_engine_name.length= name.length;
-  }
   bool resolve_storage_engine_with_error(THD *thd,
                                          handlerton **ha,
                                          bool tmp_table);
diff --git a/sql/sql_string.h b/sql/sql_string.h
index d112a8842b9..1f21df619bf 100644
--- a/sql/sql_string.h
+++ b/sql/sql_string.h
@@ -1052,13 +1052,6 @@ public:
   }
 
   // Append with optional character set conversion from ASCII (e.g. to UCS2)
-  bool append(const LEX_STRING *ls)
-  {
-    DBUG_ASSERT(ls->length < UINT_MAX32 &&
-                ((ls->length == 0 && !ls->str) ||
-                 ls->length == strlen(ls->str)));
-    return append(ls->str, (uint32) ls->length);
-  }
   bool append(const LEX_CSTRING *ls)
   {
     DBUG_ASSERT(ls->length < UINT_MAX32 &&
diff --git a/sql/vers_string.h b/sql/vers_string.h
index c5be9c359e3..93740ea8523 100644
--- a/sql/vers_string.h
+++ b/sql/vers_string.h
@@ -57,9 +57,6 @@ public:
   Lex_cstring_with_compare(const char *_str, size_t _len) :
     Lex_cstring(_str, _len)
   { }
-  Lex_cstring_with_compare(const LEX_STRING src) :
-    Lex_cstring(src.str, src.length)
-  { }
   Lex_cstring_with_compare(const LEX_CSTRING src) : Lex_cstring(src.str, src.length)
   { }
   Lex_cstring_with_compare(const char *_str) : Lex_cstring(_str, strlen(_str))
diff --git a/storage/spider/spd_malloc.cc b/storage/spider/spd_malloc.cc
index 56f8218853b..9b87560d218 100644
--- a/storage/spider/spd_malloc.cc
+++ b/storage/spider/spd_malloc.cc
@@ -861,7 +861,7 @@ bool spider_string::append(
   DBUG_ASSERT(mem_calc_inited);
   DBUG_ASSERT((!current_alloc_mem && !str.is_alloced()) ||
     current_alloc_mem == str.alloced_length());
-  bool res = str.append(ls);
+  bool res = str.append(*ls);
   SPIDER_STRING_CALC_MEM;
   DBUG_RETURN(res);
 }