Remove no-op calls to decode-char with 'ucs' arg

* lisp/gnus/mm-util.el (mm-ucs-to-char):
* lisp/language/hanja-util.el (hangul-to-hanja-char):
* lisp/leim/quail/hangul.el (hangul3-input-method-internal)
(hangul390-input-method-internal):
* lisp/nxml/rng-cmpct.el (rng-c-process-escapes):
* lisp/nxml/xsd-regexp.el (xsdre-compile-single-char)
(xsdre-range-list-to-char-alternative):
* lisp/xml.el (xml-parse-string, xml--entity-replacement-text)
(xml-substitute-special): Remove calls to decode-char where first
argument is 'ucs'; that is now a no-op.  Discussed in Bug#52263.

* lisp/nxml/xmltok.el (xmltok-unicode-to-char): Make into obsolete
function alias for 'identity'.  Update single caller.

7 files changed, 16 insertions, 22 deletions

diff --git a/lisp/gnus/mm-util.el b/lisp/gnus/mm-util.el
index 92e04f9d2ee..ddc228e4900 100644
--- a/lisp/gnus/mm-util.el
+++ b/lisp/gnus/mm-util.el
@@ -31,7 +31,7 @@
 
 (defun mm-ucs-to-char (codepoint)
   "Convert Unicode codepoint to character."
-  (or (decode-char 'ucs codepoint) ?#))
+  (or codepoint ?#))
 
 (defvar mm-coding-system-list nil)
 (defun mm-get-coding-system-list ()
diff --git a/lisp/language/hanja-util.el b/lisp/language/hanja-util.el
index 9e9213536cb..fe6323d42ba 100644
--- a/lisp/language/hanja-util.el
+++ b/lisp/language/hanja-util.el
@@ -6573,8 +6573,8 @@ The value is a hanja character that is selected interactively."
            (hanja-filter (lambda (x) (car x))
                          (mapcar (lambda (c)
                                    (if (listp c)
-                                       (cons (decode-char 'ucs (car c)) (cdr c))
-                                     (list (decode-char 'ucs c))))
+                                       (cons (car c) (cdr c))
+                                     (list c)))
                                  (aref hanja-table char)))))
     (unwind-protect
         (when (aref hanja-conversions 2)
diff --git a/lisp/leim/quail/hangul.el b/lisp/leim/quail/hangul.el
index c03e86b33c0..d069b5b68e1 100644
--- a/lisp/leim/quail/hangul.el
+++ b/lisp/leim/quail/hangul.el
@@ -429,7 +429,7 @@ When a Korean input method is off, convert the following hangul character."
            (hangul3-input-method-jong char))
           (t
            (setq hangul-queue (make-vector 6 0))
-           (insert (decode-char 'ucs char))
+           (insert char)
            (move-overlay quail-overlay (point) (point))))))
 
 (defun hangul3-input-method (key)
@@ -476,7 +476,7 @@ When a Korean input method is off, convert the following hangul character."
            (hangul3-input-method-jong char))
           (t
            (setq hangul-queue (make-vector 6 0))
-           (insert (decode-char 'ucs char))
+           (insert char)
            (move-overlay quail-overlay (point) (point))))))
 
 (defun hangul390-input-method (key)
diff --git a/lisp/nxml/rng-cmpct.el b/lisp/nxml/rng-cmpct.el
index dd3000773fd..1476aa0e5a3 100644
--- a/lisp/nxml/rng-cmpct.el
+++ b/lisp/nxml/rng-cmpct.el
@@ -369,7 +369,7 @@ OVERRIDE is either nil, require or t."
     (while (re-search-forward "\\\\x+{\\([[:xdigit:]]+\\)}"
                               (point-max)
                               t)
-      (let* ((ch (decode-char 'ucs (string-to-number (match-string 1) 16))))
+      (let* ((ch (string-to-number (match-string 1) 16)))
         (if (and ch (> ch 0))
             (let ((begin (match-beginning 0))
                   (end (match-end 0)))
diff --git a/lisp/nxml/xmltok.el b/lisp/nxml/xmltok.el
index 6159e00c511..ecad501a644 100644
--- a/lisp/nxml/xmltok.el
+++ b/lisp/nxml/xmltok.el
@@ -943,7 +943,6 @@ and VALUE-END, otherwise a STRING giving the value."
         (let ((n (string-to-number (buffer-substring-no-properties start end)
                                 base)))
           (cond ((and (integerp n) (xmltok-valid-char-p n))
-                 (setq n (xmltok-unicode-to-char n))
                  (and n (string n)))
                 (t
                  (xmltok-add-error "Invalid character code" start end)
@@ -971,11 +970,6 @@ and VALUE-END, otherwise a STRING giving the value."
         (t (and (> n #xFFFF)
                 (< n #x110000)))))
 
-(defun xmltok-unicode-to-char (n)
-  "Return the character corresponding to Unicode scalar value N.
-Return nil if unsupported in Emacs."
-  (decode-char 'ucs n))
-
 ;;; Prolog parsing
 
 (defvar xmltok-contains-doctype nil)
@@ -1766,6 +1760,10 @@ and `xmltok-namespace-attributes'."
                  xmltok-type))
     (message "Scanned end of file")))
 
+;;; Obsolete
+
+(define-obsolete-function-alias 'xmltok-unicode-to-char #'identity "29.1")
+
 (provide 'xmltok)
 
 ;;; xmltok.el ends here
diff --git a/lisp/nxml/xsd-regexp.el b/lisp/nxml/xsd-regexp.el
index 3c29803ab97..d6eaf7cc4bc 100644
--- a/lisp/nxml/xsd-regexp.el
+++ b/lisp/nxml/xsd-regexp.el
@@ -287,7 +287,7 @@ and whose tail is ACCUM."
 (defun xsdre-compile-single-char (ch)
   (if (memq ch '(?. ?* ?+ ?? ?\[ ?\] ?^ ?$ ?\\))
       (string ?\\ ch)
-    (string (decode-char 'ucs ch))))
+    (string ch)))
 
 (defun xsdre-char-class-to-range-list (cc)
   "Return a range-list for a symbolic char-class CC."
@@ -404,10 +404,6 @@ consisting of a single char alternative delimited with []."
                     (cons last chars)
                   (cons last (cons ?- chars))))))
       (setq range-list (cdr range-list)))
-    (setq chars
-          (mapcar (lambda (c)
-                    (decode-char 'ucs c))
-                  chars))
     (when caret
       (setq chars (cons ?^ chars)))
     (when hyphen
diff --git a/lisp/xml.el b/lisp/xml.el
index 0282e3741c0..e2ba02e1952 100644
--- a/lisp/xml.el
+++ b/lisp/xml.el
@@ -612,8 +612,8 @@ references."
         (if (setq ref (match-string 2))
             (progn  ; Numeric char reference
               (setq val (save-match-data
-                          (decode-char 'ucs (string-to-number
-                                             ref (if (match-string 1) 16)))))
+                          (string-to-number
+                           ref (if (match-string 1) 16))))
               (and (null val)
                    xml-validating-parser
                    (error "XML: (Validity) Invalid character reference `%s'"
@@ -898,11 +898,11 @@ references and parameter-entity references."
             ref val)
         (cond ((setq ref (match-string 1 string))
                ;; Decimal character reference
-               (setq val (decode-char 'ucs (string-to-number ref)))
+               (setq val (string-to-number ref))
                (if val (push (string val) children)))
               ;; Hexadecimal character reference
               ((setq ref (match-string 2 string))
-               (setq val (decode-char 'ucs (string-to-number ref 16)))
+               (setq val (string-to-number ref 16))
                (if val (push (string val) children)))
               ;; Parameter entity reference
               ((setq ref (match-string 3 string))
@@ -962,7 +962,7 @@ STRING is assumed to occur in an XML attribute value."
         (if ref
             ;; [4.6] Character references are included as
             ;; character data.
-            (let ((val (decode-char 'ucs (string-to-number ref (if is-hex 16)))))
+            (let ((val (string-to-number ref (if is-hex 16))))
               (push (cond (val (string val))
                           (xml-validating-parser
                            (error "XML: (Validity) Undefined character `x%s'" ref))