Conflate Qnil and Qunbound for `symbol-function'.

* src/alloc.c (Fmake_symbol): Initialize `function' to Qnil.
* src/lread.c (init_obarray): Set `function' fields to Qnil.
* src/eval.c (Fcommandp): Ignore Qunbound.
(Fautoload, eval_sub, Fapply, Ffuncall, Fmacroexpand):
* src/data.c (Ffset, Ffboundp, indirect_function, Findirect_function):
Test NILP rather than Qunbound.
(Ffmakunbound): Set to Qnil.
(Fsymbol_function): Never signal an error.
(Finteractive_form): Ignore Qunbound.

1 files changed, 4 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 6ef093991ae..a66a3858e0e 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -52,6 +52,10 @@ It is layered as:
 
 * Incompatible Lisp Changes in Emacs 24.4
 
+** nil and "unbound" are indistinguishable in symbol-function.
+`symbol-function' never signals `void-function' any more.
+`fboundp' returns non-nil if the symbol was `fset' to nil.
+
 ** `defadvice' does not honor the `freeze' flag and cannot advise
 special-forms any more.