diff --git a/ChangeLog b/ChangeLog
index fba76adf..4310b265 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2009-04-06  Eric Blake  <ebb9@byu.net>
 
+	Handle shell comments in AT_CHECK.
+	* lib/autotest/general.m4 (_AT_DECIDE_TRACEABLE): Handle # in
+	test correctly.  Latent bug in handling shell comment was first
+	fixed 2008-11-20, but regressed two patches later.
+	* tests/autotest.at (Shell comment in command): New test.
+	* NEWS: Document the fix.
+
 	Hard fail any test with syntax errors.
 	* lib/autotest/general.m4 (AT_INIT) <at_fn_group_postprocess>:
 	Guarantee test failure on syntax error, rather than inheriting
diff --git a/NEWS b/NEWS
index 23110ac1..e91fc393 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,12 @@
 GNU Autoconf NEWS - User visible changes.
 
+* Major changes in Autoconf 2.64 (2009-??-??) [stable]
+  Released by Eric Blake, based on git versions 2.63b.*.
+
+** Ensure AT_CHECK can support commands that include a # given with
+   proper m4 quoting.  For shell comments, this is a new feature; for
+   non-shell comments, this fixes a regression introduced in 2.63b.
+
 * Major changes in Autoconf 2.63b (2009-03-31) [beta]
   Released by Eric Blake, based on git versions 2.63.*.
 
diff --git a/lib/autotest/general.m4 b/lib/autotest/general.m4
index 77058544..11a067cc 100644
--- a/lib/autotest/general.m4
+++ b/lib/autotest/general.m4
@@ -1997,7 +1997,7 @@ at_fn_check_prepare_notrace],
 dnl We know at build time that tracing COMMANDS is always safe.
 [[at_fn_check_prepare_trace],]dnl
 dnl COMMANDS may contain parameter expansions; expand them at runtime.
-[[at_fn_check_prepare_dynamic "AS_ESCAPE([$1], [`\"])"])[]]dnl
+[[at_fn_check_prepare_dynamic "AS_ESCAPE([[$1]], [`\"])"])[]]dnl
 [_m4_popdef([at_reason])])
 
 
diff --git a/tests/autotest.at b/tests/autotest.at
index a49ea1b7..c5a8b586 100644
--- a/tests/autotest.at
+++ b/tests/autotest.at
@@ -322,6 +322,12 @@ bar
   [AT_NO_CMDSUBST])
 
 
+AT_CHECK_AT_TEST([Shell comment in command],
+  [my_echo=echo
+   AT_CHECK([$my_echo one [#] two], [], [one
+])])
+
+
 ## ------------------------- ##
 ## ${...} in test commands.  ##
 ## ------------------------- ##