--- a/src/ChangeLog	Thu Mar 10 19:14:25 2011 +0000
+++ b/src/ChangeLog	Fri Mar 11 20:40:01 2011 +0000
@@ -1,3 +1,10 @@
+2011-03-11  Aidan Kehoe  <kehoea@parhasard.net>
+
+	* bytecode.c (optimize_byte_code):
+	Only transform assignments to keywords to Bdiscard if
+	NEED_TO_HANDLE_21_4_CODE is turned on. Cf. similar code in
+	reject_constant_symbols().
+
 2011-02-24  Aidan Kehoe  <kehoea@parhasard.net>
 
 	* fns.c (Fsubstring_no_properties):

--- a/src/bytecode.c	Thu Mar 10 19:14:25 2011 +0000
+++ b/src/bytecode.c	Fri Mar 11 20:40:01 2011 +0000
@@ -1961,11 +1961,14 @@
 	    wtaerror ("attempt to set non-symbol", val);
 	  if (EQ (val, Qnil) || EQ (val, Qt))
 	    signal_error (Qsetting_constant, 0, val);
+#ifdef NEED_TO_HANDLE_21_4_CODE
 	  /* Ignore assignments to keywords by converting to Bdiscard.
-	     For backward compatibility only - we'd like to make this an error.  */
+	     For backward compatibility only - we'd like to make this an
+	     error.  */
 	  if (SYMBOL_IS_KEYWORD (val))
 	    REWRITE_OPCODE (Bdiscard);
 	  else
+#endif
 	    WRITE_NARGS (Bvarset);
 	  break;
 

--- a/tests/ChangeLog	Thu Mar 10 19:14:25 2011 +0000
+++ b/tests/ChangeLog	Fri Mar 11 20:40:01 2011 +0000
@@ -1,3 +1,18 @@
+2011-03-11  Aidan Kehoe  <kehoea@parhasard.net>
+
+	* automated/byte-compiler-tests.el:
+	(defconst :foo 1) now gives a warning when byte-compiled, check
+	for that.
+	(setq :foo 1) now errors with interpreted code, but succeeds with
+	byte-compiled code; check for the former, wrap a
+	Known-Bug-Expect-Failure around a check for the error in the
+	latter case, we can't yet remove this behaviour while we're using
+	packages compiled by 21.4.
+	* automated/lisp-tests.el (wrong-type-argument):
+	Integer zero is a valid argument to #'substring-no-properties, use
+	Assert not Check-Error for it. Check some other aspects of the
+	functionality of #'substring-no-properties in passing.
+
 2011-02-24  Aidan Kehoe  <kehoea@parhasard.net>
 
 	* automated/lisp-tests.el (substring-no-properties):

--- a/tests/automated/byte-compiler-tests.el	Thu Mar 10 19:14:25 2011 +0000
+++ b/tests/automated/byte-compiler-tests.el	Fri Mar 11 20:40:01 2011 +0000
@@ -45,7 +45,7 @@
 (check-byte-compiler-message "Attempt to set non-symbol" (setq 1 1))
 (check-byte-compiler-message "Attempt to set constant symbol" (setq t 1))
 (check-byte-compiler-message "Attempt to set constant symbol" (setq nil 1))
-(check-byte-compiler-message "^$" (defconst :foo 1))
+(check-byte-compiler-message "Attempt to set constant symbol" (defconst :foo 1))
 
 (check-byte-compiler-message "Attempt to let-bind non-symbol" (let ((1 'x)) 1))
 (check-byte-compiler-message "Attempt to let-bind constant symbol" (let ((t 'x)) (foo)))
@@ -60,12 +60,16 @@
 (check-byte-compiler-message "reference to free variable" (car free-variable))
 (check-byte-compiler-message "called with 2 args, but requires 1" (car 'x 'y))
 
-(check-byte-compiler-message "^$" (setq :foo 1))
 (let ((fun '(lambda () (setq :foo 1))))
   (fset 'test-byte-compiler-fun fun))
 (Check-Error setting-constant (test-byte-compiler-fun))
-(byte-compile 'test-byte-compiler-fun)
-(Check-Error setting-constant (test-byte-compiler-fun))
+(Check-Message "Attempt to set constant symbol"
+               (byte-compile 'test-byte-compiler-fun))
+
+;; Once NEED_TO_HANDLE_21_4_CODE is no longer defined in C, this will error
+;; correctly. It's disabled because the packages are compiled by 21.4.
+(Known-Bug-Expect-Failure
+ (Check-Error setting-constant (test-byte-compiler-fun)))
 
 (eval-when-compile (defvar setq-test-foo nil) (defvar setq-test-bar nil))
 (progn

--- a/tests/automated/lisp-tests.el	Thu Mar 10 19:14:25 2011 +0000
+++ b/tests/automated/lisp-tests.el	Fri Mar 11 20:40:01 2011 +0000
@@ -1339,9 +1339,17 @@
 (Check-Error args-out-of-range (subseq [1 2 3] -42))
 (Check-Error args-out-of-range (subseq [1 2 3] 0 42))
 
-(Check-Error wrong-type-argument (substring-no-properties nil 4))
-(Check-Error wrong-type-argument (substring-no-properties "hi there" pi))
-(Check-Error wrong-type-argument (substring-no-properties "hi there" 0))
+(let ((string "hi there"))
+  (Assert (equal (substring-no-properties "123" 0) "123"))
+  (Assert (equal (substring-no-properties "1234" -3 -1) "23"))
+  (Assert (equal (substring-no-properties "hi there" 0) "hi there"))
+  (put-text-property 0 (length string) 'foo 'bar string)
+  (Assert (eq 'bar (get-text-property 0 'foo string)))
+  (Assert (not
+           (get-text-property 0 'foo (substring-no-properties "hi there" 0))))
+  (Check-Error wrong-type-argument (substring-no-properties nil 4))
+  (Check-Error wrong-type-argument (substring-no-properties "hi there" pi))
+  (Check-Error wrong-type-argument (substring-no-properties "hi there" 0.0)))
 
 ;;-----------------------------------------------------
 ;; Time-related tests