Small doc updates for generalized variables

* lisp/emacs-lisp/gv.el (gv-letplace): Fix doc typo.
(gv-define-simple-setter): Update doc of `fix-return'.

* doc/lispref/variables.texi (Adding Generalized Variables):
Update description of FIX-RETURN expansion.

* doc/misc/cl.texi (Obsolete Setf Customization):
Revert defsetf example to the more correct let rather than prog1.

1 files changed, 6 insertions, 2 deletions

diff --git a/lisp/emacs-lisp/gv.el b/lisp/emacs-lisp/gv.el
index a0c412a9504..145c48c670e 100644
--- a/lisp/emacs-lisp/gv.el
+++ b/lisp/emacs-lisp/gv.el
@@ -111,7 +111,7 @@ DO must return an Elisp expression."
 GETTER will be bound to a copyable expression that returns the value
 of PLACE.
 SETTER will be bound to a function that takes an expression V and returns
-and new expression that sets PLACE to V.
+a new expression that sets PLACE to V.
 BODY should return some Elisp expression E manipulating PLACE via GETTER
 and SETTER.
 The returned value will then be an Elisp expression that first evaluates
@@ -209,8 +209,12 @@ to be pure and copyable.  Example use:
 This macro is an easy-to-use substitute for `gv-define-expander' that works
 well for simple place forms.  Assignments of VAL to (NAME ARGS...) are
 turned into calls of the form (SETTER ARGS... VAL).
+
 If FIX-RETURN is non-nil, then SETTER is not assumed to return VAL and
-instead the assignment is turned into (prog1 VAL (SETTER ARGS... VAL))
+instead the assignment is turned into something equivalent to
+  \(let ((temp VAL))
+    (SETTER ARGS... temp)
+    temp)
 so as to preserve the semantics of `setf'."
   (declare (debug (sexp (&or symbolp lambda-expr) &optional sexp)))
   `(gv-define-setter ,name (val &rest args)