45009: POSIX_CD needs to suppress some forms of option.

Otherwise forms of argument allowed by POSIX are interpreted as
options instead.

Doc/Zsh/builtins.yo

@@ -290,6 +290,8 @@ of the list shown by the tt(dirs) command, starting with zero.
 An argument of the form `tt(-)var(n)' counts from the right.
 If the tt(PUSHD_MINUS) option is set, the meanings of `tt(PLUS())'
 and `tt(-)' in this context are swapped.
+If the tt(POSIX_CD) option is set, this form of tt(cd) is not recognised
+and will be interpreted as the first form.
 
 If the tt(-q) (quiet) option is specified, the hook function tt(chpwd)
 and the functions in the array tt(chpwd_functions) are not called.

Doc/Zsh/options.yo

@@ -148,7 +148,8 @@ ifzman(zmanref(zshbuiltins))\
 ifnzman(noderef(Shell Builtin Commands)).
 If the option is set, the shell does not test for directories beneath
 the local directory (`tt(.)') until after all directories in tt(cdpath)
-have been tested.
+have been tested, and the tt(cd) and tt(chdir) commands do not recognise
+arguments of the form `{tt(PLUS())|tt(-)}var(n)' as directory stack entries.
 
 Also, if the option is set, the conditions under which the shell
 prints the new directory after changing to it are modified.  It is

Src/builtin.c

@@ -912,7 +912,7 @@ cd_get_dest(char *nam, char **argv, int hard, int func)
 	char *end;
 
 	doprintdir++;
-	if (argv[0][1] && (argv[0][0] == '+' || argv[0][0] == '-')
+	if (!isset(POSIXCD) && argv[0][1] && (argv[0][0] == '+' || argv[0][0] == '-')
 	    && strspn(argv[0]+1, "0123456789") == strlen(argv[0]+1)) {
 	    dd = zstrtol(argv[0] + 1, &end, 10);
 	    if (*end == '\0') {