diff --git a/include/m_ctype.h b/include/m_ctype.h
index 33362045284..2f5899704c7 100644
--- a/include/m_ctype.h
+++ b/include/m_ctype.h
@@ -1932,6 +1932,52 @@ my_strcasecmp_latin1(const char *a, const char *b)
 int my_wc_mb_utf8mb4_bmp_only(CHARSET_INFO *cs, my_wc_t wc, uchar *r,
                               uchar *e);
 
+#ifdef __cplusplus
+
+class String_copy_status: protected MY_STRCOPY_STATUS
+{
+public:
+  const char *source_end_pos() const
+  { return m_source_end_pos; }
+  const char *well_formed_error_pos() const
+  { return m_well_formed_error_pos; }
+};
+
+
+class Well_formed_prefix_status: public String_copy_status
+{
+public:
+  Well_formed_prefix_status(CHARSET_INFO *cs,
+                            const char *str, const char *end, size_t nchars)
+  { cs->well_formed_char_length(str, end, nchars, this); }
+};
+
+
+class Well_formed_prefix: public Well_formed_prefix_status
+{
+  const char *m_str; // The beginning of the string
+public:
+  Well_formed_prefix(CHARSET_INFO *cs, const char *str, const char *end,
+                     size_t nchars)
+   :Well_formed_prefix_status(cs, str, end, nchars), m_str(str)
+  { }
+  Well_formed_prefix(CHARSET_INFO *cs, const char *str, size_t length,
+                     size_t nchars)
+   :Well_formed_prefix_status(cs, str, str + length, nchars), m_str(str)
+  { }
+  Well_formed_prefix(CHARSET_INFO *cs, const char *str, size_t length)
+   :Well_formed_prefix_status(cs, str, str + length, length), m_str(str)
+  { }
+  Well_formed_prefix(CHARSET_INFO *cs, LEX_CSTRING str, size_t nchars)
+   :Well_formed_prefix_status(cs, str.str, str.str + str.length, nchars),
+    m_str(str.str)
+  { }
+  size_t length() const { return m_source_end_pos - m_str; }
+};
+
+#endif /* __cplusplus */
+
+
 #ifdef	__cplusplus
 }
 #endif
diff --git a/sql/lex_ident_cli.h b/sql/lex_ident_cli.h
new file mode 100644
index 00000000000..438354dda4b
--- /dev/null
+++ b/sql/lex_ident_cli.h
@@ -0,0 +1,122 @@
+/* Copyright (c) 2000, 2019, Oracle and/or its affiliates.
+   Copyright (c) 2010, 2024, MariaDB Corporation.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
+
+
+#ifndef LEX_IDENT_CLI
+#define LEX_IDENT_CLI
+
+#include "my_global.h"
+#include "m_ctype.h"
+
+
+/**
+  A string with metadata. Usually points to a string in the client
+  character set, but unlike Lex_ident_cli_st (see below) it does not
+  necessarily point to a query fragment. It can also point to memory
+  of other kinds (e.g. an additional THD allocated memory buffer
+  not overlapping with the current query text).
+
+  We'll add more flags here eventually, to know if the string has, e.g.:
+  - multi-byte characters
+  - bad byte sequences
+  - backslash escapes:   'a\nb'
+  and reuse the original query fragments instead of making the string
+  copy too early, in Lex_input_stream::get_text().
+  This will allow to avoid unnecessary copying, as well as
+  create more optimal Item types in sql_yacc.yy
+*/
+struct Lex_string_with_metadata_st: public LEX_CSTRING
+{
+private:
+  bool m_is_8bit; // True if the string has 8bit characters
+  char m_quote;   // Quote character, or 0 if not quoted
+public:
+  void set_8bit(bool is_8bit) { m_is_8bit= is_8bit; }
+  void set_metadata(bool is_8bit, char quote)
+  {
+    m_is_8bit= is_8bit;
+    m_quote= quote;
+  }
+  void set(const char *s, size_t len, bool is_8bit, char quote)
+  {
+    str= s;
+    length= len;
+    set_metadata(is_8bit, quote);
+  }
+  void set(const LEX_CSTRING *s, bool is_8bit, char quote)
+  {
+    ((LEX_CSTRING &)*this)= *s;
+    set_metadata(is_8bit, quote);
+  }
+  bool is_8bit() const { return m_is_8bit; }
+  bool is_quoted() const { return m_quote != '\0'; }
+  char quote() const { return m_quote; }
+  // Get string repertoire by the 8-bit flag and the character set
+  my_repertoire_t repertoire(CHARSET_INFO *cs) const
+  {
+    return !m_is_8bit && my_charset_is_ascii_based(cs) ?
+           MY_REPERTOIRE_ASCII : MY_REPERTOIRE_UNICODE30;
+  }
+  // Get string repertoire by the 8-bit flag, for ASCII-based character sets
+  my_repertoire_t repertoire() const
+  {
+    return !m_is_8bit ? MY_REPERTOIRE_ASCII : MY_REPERTOIRE_UNICODE30;
+  }
+};
+
+
+/*
+  Used to store identifiers in the client character set.
+  Points to a query fragment.
+*/
+struct Lex_ident_cli_st: public Lex_string_with_metadata_st
+{
+public:
+  void set_keyword(const char *s, size_t len)
+  {
+    set(s, len, false, '\0');
+  }
+  void set_ident(const char *s, size_t len, bool is_8bit)
+  {
+    set(s, len, is_8bit, '\0');
+  }
+  void set_ident_quoted(const char *s, size_t len, bool is_8bit, char quote)
+  {
+    set(s, len, is_8bit, quote);
+  }
+  void set_unquoted(const LEX_CSTRING *s, bool is_8bit)
+  {
+    set(s, is_8bit, '\0');
+  }
+  const char *pos() const { return str - is_quoted(); }
+  const char *end() const { return str + length + is_quoted(); }
+};
+
+
+class Lex_ident_cli: public Lex_ident_cli_st
+{
+public:
+  Lex_ident_cli(const LEX_CSTRING *s, bool is_8bit)
+  {
+    set_unquoted(s, is_8bit);
+  }
+  Lex_ident_cli(const char *s, size_t len)
+  {
+    set_ident(s, len, false);
+  }
+};
+
+#endif // LEX_IDENT_CLI
diff --git a/sql/lex_ident_sys.h b/sql/lex_ident_sys.h
new file mode 100644
index 00000000000..e49c3bec3c2
--- /dev/null
+++ b/sql/lex_ident_sys.h
@@ -0,0 +1,75 @@
+/* Copyright (c) 2000, 2019, Oracle and/or its affiliates.
+   Copyright (c) 2010, 2024, MariaDB Corporation.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
+
+
+#ifndef LEX_IDENT_SYS
+#define LEX_IDENT_SYS
+
+#include "lex_ident_cli.h"
+#include "sql_alloc.h"
+
+extern "C" MYSQL_PLUGIN_IMPORT CHARSET_INFO *system_charset_info;
+
+struct Lex_ident_sys_st: public LEX_CSTRING, Sql_alloc
+{
+public:
+  bool copy_ident_cli(const THD *thd, const Lex_ident_cli_st *str);
+  bool copy_keyword(const THD *thd, const Lex_ident_cli_st *str);
+  bool copy_sys(const THD *thd, const LEX_CSTRING *str);
+  bool convert(const THD *thd, const LEX_CSTRING *str, CHARSET_INFO *cs);
+  bool copy_or_convert(const THD *thd, const Lex_ident_cli_st *str,
+                       CHARSET_INFO *cs);
+  bool is_null() const { return str == NULL; }
+  bool to_size_number(ulonglong *to) const;
+  void set_valid_utf8(const LEX_CSTRING *name)
+  {
+    DBUG_ASSERT(Well_formed_prefix(system_charset_info, name->str,
+                                   name->length).length() == name->length);
+    str= name->str ; length= name->length;
+  }
+};
+
+
+class Lex_ident_sys: public Lex_ident_sys_st
+{
+public:
+  Lex_ident_sys(const THD *thd, const Lex_ident_cli_st *str)
+  {
+    if (copy_ident_cli(thd, str))
+      *this= Lex_ident_sys();
+  }
+  Lex_ident_sys()
+  {
+    ((LEX_CSTRING &) *this)= {nullptr, 0};
+  }
+  Lex_ident_sys(const char *name, size_t length)
+  {
+    LEX_CSTRING tmp= {name, length};
+    set_valid_utf8(&tmp);
+  }
+  Lex_ident_sys(const THD *thd, const LEX_CSTRING *str)
+  {
+    set_valid_utf8(str);
+  }
+  Lex_ident_sys & operator=(const Lex_ident_sys_st &name)
+  {
+    Lex_ident_sys_st::operator=(name);
+    return *this;
+  }
+};
+
+
+#endif // LEX_IDENT_SYS
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 3f4af2fa940..0cee544795c 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -21,6 +21,7 @@
 #ifndef SQL_LEX_INCLUDED
 #define SQL_LEX_INCLUDED
 
+#include "lex_ident_sys.h"
 #include "violite.h"                            /* SSL_type */
 #include "sql_trigger.h"
 #include "thr_lock.h"                  /* thr_lock_type, TL_UNLOCK */
@@ -47,153 +48,6 @@ typedef Bitmap<SELECT_NESTING_MAP_SIZE> nesting_map;
 /* YACC and LEX Definitions */
 
 
-/**
-  A string with metadata. Usually points to a string in the client
-  character set, but unlike Lex_ident_cli_st (see below) it does not
-  necessarily point to a query fragment. It can also point to memory
-  of other kinds (e.g. an additional THD allocated memory buffer
-  not overlapping with the current query text).
-
-  We'll add more flags here eventually, to know if the string has, e.g.:
-  - multi-byte characters
-  - bad byte sequences
-  - backslash escapes:   'a\nb'
-  and reuse the original query fragments instead of making the string
-  copy too early, in Lex_input_stream::get_text().
-  This will allow to avoid unnecessary copying, as well as
-  create more optimal Item types in sql_yacc.yy
-*/
-struct Lex_string_with_metadata_st: public LEX_CSTRING
-{
-private:
-  bool m_is_8bit; // True if the string has 8bit characters
-  char m_quote;   // Quote character, or 0 if not quoted
-public:
-  void set_8bit(bool is_8bit) { m_is_8bit= is_8bit; }
-  void set_metadata(bool is_8bit, char quote)
-  {
-    m_is_8bit= is_8bit;
-    m_quote= quote;
-  }
-  void set(const char *s, size_t len, bool is_8bit, char quote)
-  {
-    str= s;
-    length= len;
-    set_metadata(is_8bit, quote);
-  }
-  void set(const LEX_CSTRING *s, bool is_8bit, char quote)
-  {
-    ((LEX_CSTRING &)*this)= *s;
-    set_metadata(is_8bit, quote);
-  }
-  bool is_8bit() const { return m_is_8bit; }
-  bool is_quoted() const { return m_quote != '\0'; }
-  char quote() const { return m_quote; }
-  // Get string repertoire by the 8-bit flag and the character set
-  my_repertoire_t repertoire(CHARSET_INFO *cs) const
-  {
-    return !m_is_8bit && my_charset_is_ascii_based(cs) ?
-           MY_REPERTOIRE_ASCII : MY_REPERTOIRE_UNICODE30;
-  }
-  // Get string repertoire by the 8-bit flag, for ASCII-based character sets
-  my_repertoire_t repertoire() const
-  {
-    return !m_is_8bit ? MY_REPERTOIRE_ASCII : MY_REPERTOIRE_UNICODE30;
-  }
-};
-
-
-/*
-  Used to store identifiers in the client character set.
-  Points to a query fragment.
-*/
-struct Lex_ident_cli_st: public Lex_string_with_metadata_st
-{
-public:
-  void set_keyword(const char *s, size_t len)
-  {
-    set(s, len, false, '\0');
-  }
-  void set_ident(const char *s, size_t len, bool is_8bit)
-  {
-    set(s, len, is_8bit, '\0');
-  }
-  void set_ident_quoted(const char *s, size_t len, bool is_8bit, char quote)
-  {
-    set(s, len, is_8bit, quote);
-  }
-  void set_unquoted(const LEX_CSTRING *s, bool is_8bit)
-  {
-    set(s, is_8bit, '\0');
-  }
-  const char *pos() const { return str - is_quoted(); }
-  const char *end() const { return str + length + is_quoted(); }
-};
-
-
-class Lex_ident_cli: public Lex_ident_cli_st
-{
-public:
-  Lex_ident_cli(const LEX_CSTRING *s, bool is_8bit)
-  {
-    set_unquoted(s, is_8bit);
-  }
-  Lex_ident_cli(const char *s, size_t len)
-  {
-    set_ident(s, len, false);
-  }
-};
-
-
-struct Lex_ident_sys_st: public LEX_CSTRING, Sql_alloc
-{
-public:
-  bool copy_ident_cli(const THD *thd, const Lex_ident_cli_st *str);
-  bool copy_keyword(const THD *thd, const Lex_ident_cli_st *str);
-  bool copy_sys(const THD *thd, const LEX_CSTRING *str);
-  bool convert(const THD *thd, const LEX_CSTRING *str, CHARSET_INFO *cs);
-  bool copy_or_convert(const THD *thd, const Lex_ident_cli_st *str,
-                       CHARSET_INFO *cs);
-  bool is_null() const { return str == NULL; }
-  bool to_size_number(ulonglong *to) const;
-  void set_valid_utf8(const LEX_CSTRING *name)
-  {
-    DBUG_ASSERT(Well_formed_prefix(system_charset_info, name->str,
-                                   name->length).length() == name->length);
-    str= name->str ; length= name->length;
-  }
-};
-
-
-class Lex_ident_sys: public Lex_ident_sys_st
-{
-public:
-  Lex_ident_sys(const THD *thd, const Lex_ident_cli_st *str)
-  {
-    if (copy_ident_cli(thd, str))
-      ((LEX_CSTRING &) *this)= null_clex_str;
-  }
-  Lex_ident_sys()
-  {
-    ((LEX_CSTRING &) *this)= null_clex_str;
-  }
-  Lex_ident_sys(const char *name, size_t length)
-  {
-    LEX_CSTRING tmp= {name, length};
-    set_valid_utf8(&tmp);
-  }
-  Lex_ident_sys(const THD *thd, const LEX_CSTRING *str)
-  {
-    set_valid_utf8(str);
-  }
-  Lex_ident_sys & operator=(const Lex_ident_sys_st &name)
-  {
-    Lex_ident_sys_st::operator=(name);
-    return *this;
-  }
-};
-
-
 struct Lex_column_list_privilege_st
 {
   List<Lex_ident_sys> *m_columns;
diff --git a/sql/sql_string.h b/sql/sql_string.h
index 0c14290c312..e815534a33e 100644
--- a/sql/sql_string.h
+++ b/sql/sql_string.h
@@ -55,48 +55,6 @@ inline uint32 copy_and_convert(char *to, size_t to_length, CHARSET_INFO *to_cs,
 }
 
 
-class String_copy_status: protected MY_STRCOPY_STATUS
-{
-public:
-  const char *source_end_pos() const
-  { return m_source_end_pos; }
-  const char *well_formed_error_pos() const
-  { return m_well_formed_error_pos; }
-};
-
-
-class Well_formed_prefix_status: public String_copy_status
-{
-public:
-  Well_formed_prefix_status(CHARSET_INFO *cs,
-                            const char *str, const char *end, size_t nchars)
-  { cs->well_formed_char_length(str, end, nchars, this); }
-};
-
-
-class Well_formed_prefix: public Well_formed_prefix_status
-{
-  const char *m_str; // The beginning of the string
-public:
-  Well_formed_prefix(CHARSET_INFO *cs, const char *str, const char *end,
-                     size_t nchars)
-   :Well_formed_prefix_status(cs, str, end, nchars), m_str(str)
-  { }
-  Well_formed_prefix(CHARSET_INFO *cs, const char *str, size_t length,
-                     size_t nchars)
-   :Well_formed_prefix_status(cs, str, str + length, nchars), m_str(str)
-  { }
-  Well_formed_prefix(CHARSET_INFO *cs, const char *str, size_t length)
-   :Well_formed_prefix_status(cs, str, str + length, length), m_str(str)
-  { }
-  Well_formed_prefix(CHARSET_INFO *cs, LEX_CSTRING str, size_t nchars)
-   :Well_formed_prefix_status(cs, str.str, str.str + str.length, nchars),
-    m_str(str.str)
-  { }
-  size_t length() const { return m_source_end_pos - m_str; }
-};
-
-
 class String_copier: public String_copy_status,
                      protected MY_STRCONV_STATUS
 {