diff --git a/configure.ac b/configure.ac
index 110ea2909a9..cc2a597010f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4294,6 +4294,10 @@ AC_SUBST(LIBS_TERMCAP)
 AC_SUBST(TERMCAP_OBJ)
 
 # GNU/Linux-specific timer functions.
+# Bug#34618.
+if test "$opsys" = "cygwin"; then
+  emacs_cv_have_timerfd=no
+fi
 AC_CACHE_CHECK([for timerfd interface], [emacs_cv_have_timerfd],
   [AC_COMPILE_IFELSE(
      [AC_LANG_PROGRAM([[#include <sys/timerfd.h>
diff --git a/doc/lispref/minibuf.texi b/doc/lispref/minibuf.texi
index 766079d7bcd..a2b6e145502 100644
--- a/doc/lispref/minibuf.texi
+++ b/doc/lispref/minibuf.texi
@@ -1108,11 +1108,11 @@ different function to completely override the normal behavior of
 in the minibuffer to do completion.
 
 @defvar minibuffer-completion-table
-The value of this variable is the completion table used for completion
-in the minibuffer.  This is the global variable that contains what
-@code{completing-read} passes to @code{try-completion}.  It is used by
-minibuffer completion commands such as
-@code{minibuffer-complete-word}.
+The value of this variable is the completion table (@pxref{Basic
+Completion}) used for completion in the minibuffer.  This is the
+global variable that contains what @code{completing-read} passes to
+@code{try-completion}.  It is used by minibuffer completion commands
+such as @code{minibuffer-complete-word}.
 @end defvar
 
 @defvar minibuffer-completion-predicate
@@ -1770,7 +1770,8 @@ possible match, and ignore the match if the predicate returns
 @code{nil}.
 
 @item
-A flag specifying the type of completion operation to perform.  This
+A flag specifying the type of completion operation to perform; see
+@ref{Basic Completion}, for the details of those operations.  This
 flag may be one of the following values.
 
 @table @code
@@ -1841,17 +1842,26 @@ the same as for @code{display-sort-function}.
 
 @defun completion-table-dynamic function &optional switch-buffer
 This function is a convenient way to write a function that can act as
-a programmed completion function.  The argument @var{function} should be
-a function that takes one argument, a string, and returns an alist of
-possible completions of it.  It is allowed to ignore the argument and
-return a full list of all possible completions.  You can think of
-@code{completion-table-dynamic} as a transducer between that interface
+a programmed completion function.  The argument @var{function} should
+be a function that takes one argument, a string, and returns a
+completion table (@pxref{Basic Completion}) containing all the
+possible completions.  The table returned by @var{function} can also
+include elements that don't match the string argument; they are
+automatically filtered out by @code{completion-table-dynamic}.  In
+particular, @var{function} can ignore its argument and return a full
+list of all possible completions.  You can think of
+@code{completion-table-dynamic} as a transducer between @var{function}
 and the interface for programmed completion functions.
 
 If the optional argument @var{switch-buffer} is non-@code{nil}, and
 completion is performed in the minibuffer, @var{function} will be
 called with current buffer set to the buffer from which the minibuffer
 was entered.
+
+The return value of @code{completion-table-dynamic} is a function that
+can be used as the 2nd argument to @code{try-completion} and
+@code{all-completions}.  Note that this function will always return
+empty metadata and trivial boundaries (@pxref{Programmed Completion}).
 @end defun
 
 @defun completion-table-with-cache function &optional ignore-case
@@ -1876,9 +1886,10 @@ Emacs Manual}.  This command uses the abnormal hook variable
 
 @defvar completion-at-point-functions
 The value of this abnormal hook should be a list of functions, which
-are used to compute a completion table for completing the text at
-point.  It can be used by major modes to provide mode-specific
-completion tables (@pxref{Major Mode Conventions}).
+are used to compute a completion table (@pxref{Basic Completion}) for
+completing the text at point.  It can be used by major modes to
+provide mode-specific completion tables (@pxref{Major Mode
+Conventions}).
 
 When the command @code{completion-at-point} runs, it calls the
 functions in the list one by one, without any argument.  Each function
diff --git a/doc/misc/tramp.texi b/doc/misc/tramp.texi
index 3630c317b2f..db3b3f7fee5 100644
--- a/doc/misc/tramp.texi
+++ b/doc/misc/tramp.texi
@@ -3857,7 +3857,9 @@ Due to the remote shell saving tilde expansions triggered by
 @value{tramp} can suppress this behavior with the user option
 @code{tramp-histfile-override}.  When set to @code{t}, environment
 variable @env{HISTFILE} is unset, and environment variables
-@env{HISTFILESIZE} and @env{HISTSIZE} are set to 0.
+@env{HISTFILESIZE} and @env{HISTSIZE} are set to 0.  Don't use this
+with @command{bash} 5.0.0.  There is a bug in @command{bash} which
+lets @command{bash} die.
 
 Alternatively, @code{tramp-histfile-override} could be a string.
 Environment variable @env{HISTFILE} is set to this file name then.  Be
diff --git a/lisp/emacs-lisp/regexp-opt.el b/lisp/emacs-lisp/regexp-opt.el
index 152dca2309d..63786c1508c 100644
--- a/lisp/emacs-lisp/regexp-opt.el
+++ b/lisp/emacs-lisp/regexp-opt.el
@@ -121,9 +121,9 @@ than that of a simplified version:
                 ((eq paren \\='symbols) \\='(\"\\\\_<\\\\(\" . \"\\\\)\\\\_>\"))
                 ((null paren)          \\='(\"\\\\(?:\" . \"\\\\)\"))
                 (t                       \\='(\"\\\\(\" . \"\\\\)\")))))
-     (concat (car paren)
+     (concat (car parens)
              (mapconcat \\='regexp-quote strings \"\\\\|\")
-             (cdr paren))))"
+             (cdr parens))))"
   (save-match-data
     ;; Recurse on the sorted list.
     (let* ((max-lisp-eval-depth 10000)
diff --git a/src/image.c b/src/image.c
index 642bf671520..854fbe40f75 100644
--- a/src/image.c
+++ b/src/image.c
@@ -9079,8 +9079,8 @@ imagemagick_load (struct frame *f, struct image *img)
 #endif
       success_p = imagemagick_load_image (f, img, 0, 0, SSDATA (file));
     }
-  /* Else its not a file, its a lisp object.  Load the image from a
-     lisp object rather than a file.  */
+  /* Else it's not a file, it's a Lisp object.  Load the image from a
+     Lisp object rather than a file.  */
   else
     {
       Lisp_Object data;
@@ -9388,8 +9388,8 @@ svg_load (struct frame *f, struct image *img)
 				  SSDATA (ENCODE_FILE (file)));
       xfree (contents);
     }
-  /* Else its not a file, its a lisp object.  Load the image from a
-     lisp object rather than a file.  */
+  /* Else it's not a file, it's a Lisp object.  Load the image from a
+     Lisp object rather than a file.  */
   else
     {
       Lisp_Object data, original_filename;