2 files changed, 10 insertions, 3 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 0bbc1648dec..45f32afa0a8 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2010-09-27  Andreas Schwab  <schwab@linux-m68k.org>
+
+        * emacs-lisp/byte-opt.el (byte-optimize-form-code-walker): Avoid
+        infinite recursion on erroneous lambda form.  (Bug#7114)
+
 2010-09-27  Kenichi Handa  <handa@m17n.org>
 
         * tar-mode.el (tar-header-block-tokenize): Decode filenames in
diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el
index e461010a6ce..4950511ebe2 100644
--- a/lisp/emacs-lisp/byte-opt.el
+++ b/lisp/emacs-lisp/byte-opt.el
@@ -381,9 +381,11 @@
                 form))
           ((or (byte-code-function-p fn)
                (eq 'lambda (car-safe fn)))
-           (byte-optimize-form-code-walker
-            (byte-compile-unfold-lambda form)
-            for-effect))
+           (let ((newform (byte-compile-unfold-lambda form)))
+             (if (eq newform form)
+                 ;; Some error occured, avoid infinite recursion
+                 form
+               (byte-optimize-form-code-walker newform for-effect))))
           ((memq fn '(let let*))
            ;; recursively enter the optimizer for the bindings and body
            ;; of a let or let*.  This for depth-firstness: forms that