Remove POSIX 'cpoptions': '/'

runtime/doc/change.txt

@@ -714,9 +714,6 @@ When the {string} starts with "\=" it is evaluated as an expression, see
 characters.
 
 Otherwise these characters in {string} have a special meaning:
-								*:s%*
-When {string} is equal to "%" and '/' is included with the 'cpoptions' option,
-then the {string} of the previous substitute command is used, see |cpo-/|
 
 magic	nomagic	  action    ~
   &	  \&	  replaced with the whole matched pattern	     *s/\&*

runtime/doc/options.txt

@@ -1952,9 +1952,6 @@ A jump table for the options with a short description can be found at |Q_op|.
 			   '\' included: "/[ \-]"  finds <Space>, '\' and '-'
 			   '\' excluded: "/[ \-]"  finds <Space> and '-'
 			Also see |cpo-l|.
-								*cpo-/*
-		/	When "%" is used as the replacement string in a |:s|
-			command, use the previous replacement string. |:s%|
 								*cpo-.*
 		.	The ":chdir" and ":cd" commands fail if the current
 			buffer is modified, unless ! is used.  Vim doesn't

src/nvim/ex_cmds.c

@@ -3472,18 +3472,8 @@ void do_sub(exarg_T *eap)
     }
 
     if (!eap->skip) {
-      /* In POSIX vi ":s/pat/%/" uses the previous subst. string. */
-      if (STRCMP(sub, "%") == 0
-          && vim_strchr(p_cpo, CPO_SUBPERCENT) != NULL) {
-        if (old_sub == NULL) {          /* there is no previous command */
-          EMSG(_(e_nopresub));
-          return;
-        }
-        sub = old_sub;
-      } else {
-        xfree(old_sub);
-        old_sub = vim_strsave(sub);
-      }
+      xfree(old_sub);
+      old_sub = vim_strsave(sub);
     }
   } else if (!eap->skip) {    /* use previous pattern and substitution */
     if (old_sub == NULL) {      /* there is no previous command */

src/nvim/option_defs.h

@@ -129,7 +129,6 @@
 #define CPO_SPECI       '<'     /* don't recognize <> in mappings */
 #define CPO_REGAPPEND   '>'     /* insert NL when appending to a register */
 /* POSIX flags */
-#define CPO_SUBPERCENT  '/'     /* % in :s string uses previous one */
 #define CPO_BACKSL      '\\'    /* \ is not special in [] */
 #define CPO_CHDIR       '.'     /* don't chdir if buffer is modified */
 #define CPO_SCOLON      ';'     /* using "," and ";" will skip over char if
@@ -138,7 +137,7 @@
 #define CPO_VIM         "aABceFs"
 #define CPO_VI          "aAbBcCdDeEfFiIJkKlLmMnoOpPqrRsStuvWxXyZ$!%+<>;"
 #define CPO_ALL \
-  "aAbBcCdDeEfFiIJkKlLmMnoOpPqrRsStuvWxXyZ$!%+<>/\\.;"
+  "aAbBcCdDeEfFiIJkKlLmMnoOpPqrRsStuvWxXyZ$!%+<>\\.;"
 
 /* characters for p_ww option: */
 #define WW_ALL          "bshl<>[],~"

src/nvim/testdir/test80.in

@@ -126,10 +126,6 @@ TEST_6:
 STARTTEST
 :set magic&
 :$put =\"\n\nTEST_6:\"
-:set cpo+=/
-:$put =substitute('A', 'A', 'a', '')
-:$put =substitute('B', 'B', '%', '')
-:set cpo-=/
 :$put =substitute('C', 'C', 'c', '')
 :$put =substitute('D', 'D', '%', '')
 /^TEST_7

src/nvim/testdir/test80.ok

@@ -94,8 +94,6 @@ A123456789987654321
 
 
 TEST_6:
-a
-%
 c
 %