On Thu, Jun 26, 2014 at 8:21 AM, Stas Boukarev <stassats@gmail.com> wrote:

(compile nil `(lambda () (declare (ftype (function (t) fixnum) x))))
=>
The function COMPILER::TYPE-FILTER is undefined.
which stems from
http://common-lisp.net/gitweb?p=projects/mkcl/mkcl.git;a=blob;f=src/cmp/cmpenv.lsp;h=11c437566969e85449a57bf95ac5e1841e518535;hb=HEAD#l94
missing the package prefix.