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REPORTING BUGS

Bugs can be reported on the help mailing list
  sbcl-help@lists.sourceforge.net
or on the development mailing list
  sbcl-devel@lists.sourceforge.net

Please please please include enough information in a bug report
that someone reading it can reproduce the problem, i.e. don't write
     Subject: apparent bug in PRINT-OBJECT (or *PRINT-LENGTH*?)
     PRINT-OBJECT doesn't seem to work with *PRINT-LENGTH*. Is this a bug?
but instead
     Subject: apparent bug in PRINT-OBJECT (or *PRINT-LENGTH*?)
     Under sbcl-1.2.3, when I compile and load the file
       (DEFSTRUCT (FOO (:PRINT-OBJECT (LAMBDA (X Y)
					(LET ((*PRINT-LENGTH* 4))
					  (PRINT X Y)))))
	 X Y)
     then at the command line type
       (MAKE-FOO)
     the program loops endlessly instead of printing the object.


KNOWN PORT-SPECIFIC BUGS

The breakpoint-based TRACE facility doesn't work properly in the
OpenBSD port of sbcl-0.6.7.

KNOWN BUGS

(There is also some information on bugs in the manual page and in the
TODO file. Eventually more such information may move here.)

* (DESCRIBE NIL) causes an endless loop.

* The FUNCTION special operator doesn't check properly whether its
  argument is a function name. E.g. (FUNCTION (X Y)) returns a value
  instead of failing with an error.

* (DESCRIBE 'GF) fails where GF is the name of a generic function:
  The function SB-IMPL::DESCRIBE-INSTANCE is undefined.

* Failure in initialization files is not handled gracefully -- it's 
  a throw to TOP-LEVEL-CATCHER, which is not caught until we enter
  TOPLEVEL-REPL. Code should be added to catch such THROWs even when
  we're not in TOPLEVEL-REPL and do *something* with them (probably
  complaining about an error outside TOPLEVEL-REPL, perhaps printing
  a BACKTRACE, then terminating execution of SBCL).

* COMPILED-FUNCTION-P bogusly reports T for interpreted functions:
	* (DEFUN FOO (X) (- 12 X))
	FOO
	* (COMPILED-FUNCTION-P #'FOO)
	T

* The CL:STEP macro is undefined.

* DEFSTRUCT should almost certainly overwrite the old LAYOUT information
  instead of just punting when a contradictory structure definition
  is loaded.

* It should cause a STYLE-WARNING, not a full WARNING, when a structure
  slot default value does not match the declared structure slot type.
  (The current behavior is consistent with SBCL's behavior elsewhere,
  and would not be a problem, except that the other behavior is 
  specifically required by the ANSI spec.)

* It should cause a STYLE-WARNING, not a WARNING, when the system ignores
  an FTYPE proclamation for a slot accessor.

* Missing ordinary arguments in a macro call aren't reported when the 
  macro lambda list contains &KEY:
	(DEFMACRO FOO (BAR &KEY) BAR) => FOO
	(FOO) => NIL
  Also in DESTRUCTURING-BIND:
	(DESTRUCTURING-BIND (X Y &REST REST) '(1) (VECTOR X Y REST))
	=> #(1 NIL NIL)
  Also with &REST lists:
	(DEFMACRO FOO (BAR &REST REST) BAR) => FOO
	(FOO) => NIL

* Error reporting on various stream-requiring operations is not 
  very good when the stream argument has the wrong type, because
  the operation tries to fall through to Gray stream code, and then
  dies because it's undefined. E.g. 
    (PRINT-UNREADABLE-OBJECT (*STANDARD-OUTPUT* 1))
  gives the error message
    error in SB-KERNEL::UNDEFINED-SYMBOL-ERROR-HANDLER:
      The function SB-IMPL::STREAM-WRITE-STRING is undefined.
  It would be more useful and correct to signal a TYPE-ERROR:
    not a STREAM: 1
  (It wouldn't be terribly difficult to write stubs for all the 
  Gray stream functions that the old CMU CL code expects, with
  each stub just raising the appropriate TYPE-ERROR.)

* bogus warnings about undefined functions for magic functions like
  SB!C::%%DEFUN and SB!C::%DEFCONSTANT when cross-compiling files
  like src/code/float.lisp

* The "byte compiling top-level form:" output ought to be condensed.
  Perhaps any number of such consecutive lines ought to turn into a
  single "byte compiling top-level forms:" line.

* The handling of IGNORE declarations on lambda list arguments of DEFMETHOD
  is at least weird, and in fact seems broken and useless. I should 
  fix up another layer of binding, declared IGNORABLE, for typed
  lambda list arguments.

* Compiling a file containing the erroneous program
	(DEFSTRUCT FOO
	  A
	  B)
	(DEFSTRUCT (BAR (:INCLUDE FOO))
	  A
	  B)
  gives only the not-very-useful message
	caught ERROR:
	  (during macroexpansion)
	Condition PROGRAM-ERROR was signalled.
  (The specific message which says that the problem was duplicate
  slot names gets lost.)

* The way that the compiler munges types with arguments together
  with types with no arguments (in e.g. TYPE-EXPAND) leads to
  weirdness visible to the user:
	(DEFTYPE FOO () 'FIXNUM)
	(TYPEP 11 'FOO) => T
	(TYPEP 11 '(FOO)) => T, which seems weird
	(TYPEP 11 'FIXNUM) => T
	(TYPEP 11 '(FIXNUM)) signals an error, as it should
  The situation is complicated by the presence of Common Lisp types
  like UNSIGNED-BYTE (which can either be used in list form or alone)
  so I'm not 100% sure that the behavior above is actually illegal.
  But I'm 90+% sure, and someday perhaps I'll be motivated to look it up..

* It would be nice if the
	caught ERROR:
	  (during macroexpansion)
  said what macroexpansion was at fault, e.g.
	caught ERROR:
	  (during macroexpansion of IN-PACKAGE,
	  during macroexpansion of DEFFOO)

* The type system doesn't understand the KEYWORD type very well:
	(SUBTYPEP 'KEYWORD 'SYMBOL) => NIL, NIL
  It might be possible to fix this by changing the definition of
  KEYWORD to (AND SYMBOL (SATISFIES KEYWORDP)), but the type system
  would need to be a bit smarter about AND types, too:
	(SUBTYPEP '(AND SYMBOL KEYWORD) 'SYMBOL) => NIL, NIL
  (The type system does know something about AND types already,
	(SUBTYPEP '(AND INTEGER FLOAT) 'NUMBER) => T, T
	(SUBTYPEP '(AND INTEGER FIXNUM) 'NUMBER) =>T, T
  so likely this is a small patch.)

* Floating point infinities are screwed up. [When I was converting CMU CL
  to SBCL, I was looking for complexity to delete, and I thought it was safe
  to just delete support for floating point infinities. It wasn't: they're
  generated by the floating point hardware even when we remove support
  for them in software. -- WHN] Support for them should be restored.

* The ANSI syntax for non-STANDARD method combination types in CLOS is
	(DEFGENERIC FOO (X) (:METHOD-COMBINATION PROGN))
	(DEFMETHOD FOO PROGN ((X BAR)) (PRINT 'NUMBER))
  If you mess this up, omitting the PROGN qualifier in in DEFMETHOD,
	(DEFGENERIC FOO (X) (:METHOD-COMBINATION PROGN))
	(DEFMETHOD FOO ((X BAR)) (PRINT 'NUMBER))
  the error mesage is not easy to understand:
	   INVALID-METHOD-ERROR was called outside the dynamic scope
	of a method combination function (inside the body of
	DEFINE-METHOD-COMBINATION or a method on the generic
	function COMPUTE-EFFECTIVE-METHOD).
  It would be better if it were more informative, a la
	   The method combination type for this method (STANDARD) does
	not match the method combination type for the generic function
	(PROGN).
  Also, after you make the mistake of omitting the PROGN qualifier
  on a DEFMETHOD, doing a new DEFMETHOD with the correct qualifier
  no longer works:
	(DEFMETHOD FOO PROGN ((X BAR)) (PRINT 'NUMBER))
  gives
	   INVALID-METHOD-ERROR was called outside the dynamic scope
	of a method combination function (inside the body of
	DEFINE-METHOD-COMBINATION or a method on the generic
	function COMPUTE-EFFECTIVE-METHOD).
  This is not very helpful..

* The message "The top of the stack was encountered." from the debugger
  is not helpful when I type "FRAME 0" -- I know I'm going to the top
  of the stack.

* (SUBTYPEP '(FUNCTION (T BOOLEAN) NIL)
            '(FUNCTION (FIXNUM FIXNUM) NIL)) => T, T
  (Also, when this is fixed, we can enable the code in PROCLAIM which 
  checks for incompatible FTYPE redeclarations.)

* The ANSI spec says that CONS can be a compound type spec, e.g.
  (CONS FIXNUM REAL). SBCL doesn't support this.

* from Paolo Amoroso on the CMU CL mailing list 27 Feb 2000:
   I use CMU CL 18b under Linux. When COMPILE-FILE is supplied a physical
pathname, the type of the corresponding compiled file is X86F:
	* (compile-file "/home/paolo/lisp/tools/foo")
	Python version 1.0, VM version Intel x86 on 27 FEB 0 06:00:46 pm.
	Compiling: /home/paolo/lisp/tools/foo.lisp 27 FEB 0 05:57:42 pm
	Converted SQUARE.
	Compiling DEFUN SQUARE:
	Byte Compiling Top-Level Form:
	/home/paolo/lisp/tools/foo.x86f written.
	Compilation finished in 0:00:00.
	#p"/home/paolo/lisp/tools/foo.x86f"
	NIL
	NIL
But when the function is called with a logical pathname, the file type
becomes FASL:
	* (compile-file "tools:foo")
	Python version 1.0, VM version Intel x86 on 27 FEB 0 06:01:04 pm.
	Compiling: /home/paolo/lisp/tools/foo.lisp 27 FEB 0 05:57:42 pm
	Converted SQUARE.
	Compiling DEFUN SQUARE:
	Byte Compiling Top-Level Form:
	TOOLS:FOO.FASL written.
	Compilation finished in 0:00:00.
	#p"/home/paolo/lisp/tools/foo.fasl"
	NIL
	NIL

* from DTC on the CMU CL mailing list 25 Feb 2000:
;;; Compiler fails when this file is compiled.
;;;
;;; Problem shows up in delete-block within ir1util.lisp. The assertion
;;; (assert (member (functional-kind lambda) '(:let :mv-let :assignment)))
;;; fails within bind node branch.
;;;
;;; Note that if c::*check-consistency* is enabled then an un-reached
;;; entry is also reported.
;;;
(defun foo (val)
  (declare (values nil))
  nil)
(defun bug (val)
  (multiple-value-call
      #'(lambda (res)
          (block nil
            (tagbody
             loop
               (when res
                 (return nil))
               (go loop))))
    (foo val))
  (catch 'ccc1
    (throw 'ccc1
      (block bbbb
        (tagbody

           (let ((ttt #'(lambda () (go cccc))))
             (declare (special ttt))
             (return-from bbbb nil))

         cccc
           (return-from bbbb nil))))))

* (I *think* this is a bug. It certainly seems like strange behavior. But
  the ANSI spec is scary, dark, and deep..)
    (FORMAT NIL  "~,1G" 1.4) => "1.    "
    (FORMAT NIL "~3,1G" 1.4) => "1.    "

* from Marco Antoniotti on cmucl-imp mailing list 1 Mar 2000:
	(defclass ccc () ())
	(setf (find-class 'ccc1) (find-class 'ccc))
	(defmethod zut ((c ccc1)) 123)
  DTC's recommended workaround from the mailing list 3 Mar 2000:
	(setf (pcl::find-class 'ccc1) (pcl::find-class 'ccc))

* There's probably a bug in the compiler handling of special variables
  in closures, inherited from the CMU CL code, as reported on the
  CMU CL mailing list. There's a patch for this on the CMU CL
  mailing list too:
    Message-ID: <38C8E188.A1E38B5E@jeack.com.au>
    Date: Fri, 10 Mar 2000 22:50:32 +1100
    From: "Douglas T. Crosher" <dtc@jeack.com.au>

* The ANSI spec, in section "22.3.5.2 Tilde Less-Than-Sign: Logical Block",
  says that an error is signalled if ~W, ~_, ~<...~:>, ~I, or ~:T is used
  inside "~<..~>" (without the colon modifier on the closing syntax).
  However, SBCL doesn't do this:
	* (FORMAT T "~<munge~wegnum~>" 12)
	munge12egnum
	NIL

* When too many files are opened, OPEN will fail with an
  uninformative error message 
	error in function OPEN: error opening #P"/tmp/foo.lisp": NIL
  instead of saying that too many files are open.

* Right now, when COMPILE-FILE has a read error, it actually pops
  you into the debugger before giving up on the file. It should
  instead handle the error, perhaps issuing (and handling)
  a secondary error "caught ERROR: unrecoverable error during compilation"
  and then return with FAILURE-P true,

* The print system doesn't conform to ANSI
  "22.1.3.3.1 Package Prefixes for Symbols" for keywords printed when
  *PACKAGE* is the KEYWORD package.

  from a message by Ray Toy on CMU CL mailing list Fri, 28 Apr 2000:

In a discussion on comp.lang.lisp, the following code was given (by
Erik Naggum):

(let ((*package* (find-package :keyword)))
  (write-to-string object :readably t))

If OBJECT is a keyword, CMUCL prints out the keyword, but without a
colon.  Hence, it's not readable, as requested.

I think the following patch will make this work as expected.  The
patch just basically checks for the keyword package first before
checking the current package.

Ray

--- ../cmucl-18c/src/code/print.lisp    Wed Dec  8 14:33:47 1999
+++ ../cmucl-18c/new/code/print.lisp    Fri Apr 28 09:21:29 2000
@@ -605,12 +605,12 @@
       (let ((package (symbol-package object))
            (name (symbol-name object)))
        (cond
-        ;; If the symbol's home package is the current one, then a
-        ;; prefix is never necessary.
-        ((eq package *package*))
         ;; If the symbol is in the keyword package, output a colon.
         ((eq package *keyword-package*)
          (write-char #\: stream))
+        ;; If the symbol's home package is the current one, then a
+        ;; prefix is never necessary.
+        ((eq package *package*))
         ;; Uninterned symbols print with a leading #:.
         ((null package)
          (when (or *print-gensym* *print-readably*)

* from CMU CL mailing list 01 May 2000 

I realize I can take care of this by doing (proclaim (ignore pcl::.slots1.))
but seeing as .slots0. is not-exported, shouldn't it be ignored within the
+expansion
when not used?
 
In: DEFMETHOD FOO-BAR-BAZ (RESOURCE-TYPE)
  (DEFMETHOD FOO-BAR-BAZ
             ((SELF RESOURCE-TYPE))
             (SETF (SLOT-VALUE SELF 'NAME) 3))
--> BLOCK MACROLET PCL::FAST-LEXICAL-METHOD-FUNCTIONS
--> PCL::BIND-FAST-LEXICAL-METHOD-MACROS MACROLET
--> PCL::BIND-LEXICAL-METHOD-FUNCTIONS LET PCL::BIND-ARGS LET* PCL::PV-BINDING
--> PCL::PV-BINDING1 PCL::PV-ENV LET
==>
  (LET ((PCL::.SLOTS0. #))
    (PROGN SELF)
    (BLOCK FOO-BAR-BAZ
      (LET #
        #)))
Warning: Variable PCL::.SLOTS0. defined but never used.
 
Compilation unit finished.
  1 warning

#<Standard-Method FOO-BAR-BAZ (RESOURCE-TYPE) {480918FD}>

* reported by Sam Steingold on the cmucl-imp mailing list 12 May 2000:

Also, there is another bug: `array-displacement' should return an array
or nil as first value (as per ANSI CL), while CMUCL declares it as
returning an array as first value always.

* Sometimes (SB-EXT:QUIT) fails with 
	Argh! maximum interrupt nesting depth (4096) exceeded, exiting
	Process inferior-lisp exited abnormally with code 1
  I haven't noticed a repeatable case of this yet.

* The system accepts DECLAIM in most places where DECLARE would be 
  accepted, without even issuing a warning. ANSI allows this, but since
  it's fairly easy to mistype DECLAIM instead of DECLARE, and the
  meaning is rather different, and it's unlikely that the user
  has a good reason for doing DECLAIM not at top level, it would be 
  good to issue a STYLE-WARNING when this happens. A possible
  fix would be to issue STYLE-WARNINGs for DECLAIMs not at top level,
  or perhaps to issue STYLE-WARNINGs for any EVAL-WHEN not at top level.

* There seems to be some sort of bug in the interaction of the
  normal compiler, the byte compiler, and type predicates.
  Compiling and loading this file
    (IN-PACKAGE :CL-USER)
    (DEFSTRUCT FOO A B)
    (PROGN
     (DECLAIM (FTYPE (FUNCTION (FOO) FOO) FOO-BAR))
     (DECLAIM (INLINE FOO-BAR))
     (DEFUN FOO-BAR (FOO)
       (DECLARE (TYPE FOO FOO))
       (LET ((RESULT2605 (BLOCK FOO-BAR (PROGN (THE FOO (FOO-A FOO))))))
         (UNLESS (TYPEP RESULT2605 'FOO)
           (LOCALLY (ERROR "OOPS")))
         (THE FOO RESULT2605)))
     'FOO-BAR)
    (DEFPARAMETER *FOO* (MAKE-FOO :A (MAKE-FOO)))
    (UNLESS (EQ *PRINT-LEVEL* 133)
      (DEFUN CK? ()
        (LABELS ((FLOOD ()
    		    (WHEN (TYPEP *X* 'FOO)
    		      (FOO-BAR *Y*))))))
      (PRINT 11)
      (PRINT (FOO-BAR *FOO*))
      (PRINT 12))
  in sbcl-0.6.5 (or also in CMU CL 18b for FreeBSD) gives a call
  to the undefined function SB-C::%INSTANCE-TYPEP. %INSTANCE-TYPEP
  is not defined as a function because it's supposed to
  be transformed away. My guess is what's happening is that
  the mixture of toplevel and non-toplevel stuff and inlining
  is confusing the system into compiling an %INSTANCE-TYPEP
  form into byte code, where the DEFTRANSFORM which is supposed
  to get rid of such forms is not effective.

* some sort of bug in inlining and RETURN-FROM in sbcl-0.6.5: Compiling
    (DEFUN BAR? (X)
      (OR (NAR? X)
          (BLOCK USED-BY-SOME-Y?
            (FLET ((FROB (STK)
                     (DOLIST (Y STK)
                       (UNLESS (REJECTED? Y)
                         (RETURN-FROM USED-BY-SOME-Y? T)))))
              (DECLARE (INLINE FROB))
              (FROB (RSTK X))
              (FROB (MRSTK X)))
            NIL)))
  gives
   error in function SB-KERNEL:ASSERT-ERROR:
   The assertion (EQ (SB-C::CONTINUATION-KIND SB-C::CONT) :BLOCK-START) failed.

* The CMU CL reader code takes liberties in binding the standard read table
  when reading the names of characters. Tim Moore posted a patch to the 
  CMU CL mailing list Mon, 22 May 2000 21:30:41 -0700.

* In some cases the compiler believes type declarations on array
  elements without checking them, e.g.
	(DECLAIM (OPTIMIZE (SAFETY 3) (SPEED 1) (SPACE 1)))
	(DEFSTRUCT FOO A B)
	(DEFUN BAR (X)
	  (DECLARE (TYPE (SIMPLE-ARRAY CONS 1) X))
	  (WHEN (CONSP (AREF X 0))
	    (PRINT (AREF X 0))))
	(BAR (VECTOR (MAKE-FOO :A 11 :B 12)))
  prints
	#S(FOO :A 11 :B 12) 
  in SBCL 0.6.5 (and also in CMU CL 18b). This does not happen for
  all cases, e.g. the type assumption *is* checked if the array
  elements are declared to be of some structure type instead of CONS.

* The printer doesn't report closures very well. This is true in 
  CMU CL 18b as well:
    (PRINT #'CLASS-NAME)
  gives
    #<Closure Over Function "DEFUN STRUCTURE-SLOT-ACCESSOR" {134D1A1}>
  It would be nice to make closures have a settable name slot,
  and make things like DEFSTRUCT and FLET, which create closures,
  set helpful values into this slot.

* And as long as we're wishing, it would be awfully nice if INSPECT could
  also report on closures, telling about the values of the bound variables.

* as reported by Robert Strandh on the CMU CL mailing list 12 Jun 2000:
    $ cat xx.lisp
    (defconstant +a-constant+ (make-instance 'a-class))
    (defconstant +another-constant+ (vector +a-constant+))
    $ lisp
    CMU Common Lisp release x86-linux 2.4.19  8 February 2000 build 456,
    running on
    bobby
    Send bug reports and questions to your local CMU CL maintainer,
    or to pvaneynd@debian.org
    or to cmucl-help@cons.org. (prefered)
    type (help) for help, (quit) to exit, and (demo) to see the demos
    Loaded subsystems:
      Python 1.0, target Intel x86
      CLOS based on PCL version:  September 16 92 PCL (f)
    * (defclass a-class () ())
    #<STANDARD-CLASS A-CLASS {48027BD5}>
    * (compile-file "xx.lisp")
    Python version 1.0, VM version Intel x86 on 12 JUN 00 08:12:55 am.
    Compiling:
    /home/strandh/Research/Functional/Common-Lisp/CLIM/Development/McCLIM
    /xx.lisp 12 JUN 00 07:47:14 am
    Compiling Load Time Value of (PCL::GET-MAKE-INSTANCE-FUNCTION-SYMBOL
    '(A-CLASS NIL NIL)):
    Byte Compiling Top-Level Form:
    Error in function C::DUMP-STRUCTURE:  Attempt to dump invalid
    structure:
      #<A-CLASS {4803A5B5}>
    How did this happen?

* The compiler assumes that any time a function of declared FTYPE
  doesn't signal an error, its arguments were of the declared type.
  E.g. compiling and loading
    (DECLAIM (OPTIMIZE (SAFETY 3)))
    (DEFUN FACTORIAL (X) (GAMMA (1+ X)))
    (DECLAIM (FTYPE (FUNCTION (UNSIGNED-BYTE) FACTORIAL)))
    (DEFUN FOO (X)
      (COND ((> (FACTORIAL X) 1.0E6)
             (FORMAT T "too big~%"))
            ((INTEGERP X)
             (FORMAT T "exactly ~S~%" (FACTORIAL X)))
            (T
             (FORMAT T "approximately ~S~%" (FACTORIAL X)))))
  then executing
    (FOO 1.5)
  will cause the INTEGERP case to be selected, giving bogus output a la
    exactly 1.33..
  This violates the "declarations are assertions" principle.
  According to the ANSI spec, in the section "System Class FUNCTION",
  this is a case of "lying to the compiler", but the lying is done
  by the code which calls FACTORIAL with non-UNSIGNED-BYTE arguments,
  not by the unexpectedly general definition of FACTORIAL. In any case,
  "declarations are assertions" means that lying to the compiler should
  cause an error to be signalled, and should not cause a bogus
  result to be returned. Thus, the compiler should not assume
  that arbitrary functions check their argument types. (It might
  make sense to add another flag (CHECKED?) to DEFKNOWN to 
  identify functions which *do* check their argument types.)

* As pointed out by Martin Cracauer on the CMU CL mailing list
  13 Jun 2000, the :FILE-LENGTH operation for 
  FD-STREAM-MISC-ROUTINE is broken for large files: it says
  (THE INDEX SIZE) even though SIZE can be larger than INDEX.

* In SBCL 0.6.5 (and CMU CL 18b) compiling and loading
	(in-package :cl-user)
	(declaim (optimize (safety 3)
			   (debug 3)
			   (compilation-speed 2)
			   (space 1)
			   (speed 2)
			   #+nil (sb-ext:inhibit-warnings 2)))
	(declaim (ftype (function * (values)) emptyvalues))
	(defun emptyvalues (&rest rest) (declare (ignore rest)) (values))
	(defstruct foo x y)
	(defgeneric assertoid ((x t)))
	(defmethod assertoid ((x t)) "just a placeholder")
	(defun bar (ht)
	  (declare (type hash-table ht))
	  (let ((res
	         (block blockname
	           (progn
	            (prog1
			(emptyvalues)
	              (assertoid (hash-table-count ht)))))))
	    (unless (typep res 'foo)
	      (locally
	       (common-lisp-user::bad-result-from-assertive-typed-fun
	        'bar
	        res)))))
  then executing
	(bar (make-hash-table))
  causes the failure
	Error in KERNEL::UNDEFINED-SYMBOL-ERROR-HANDLER:
	  the function C::%INSTANCE-TYPEP is undefined.
  %INSTANCE-TYPEP is always supposed to be IR1-transformed away, but for
  some reason -- the (VALUES) return value declaration? -- the optimizer is
  confused and compiles a full call to %INSTANCE-TYPEP (which doesn't exist
  as a function) instead.

* DEFMETHOD doesn't check the syntax of &REST argument lists properly,
  accepting &REST even when it's not followed by an argument name:
	(DEFMETHOD FOO ((X T) &REST) NIL)

* On the CMU CL mailing list 26 June 2000, Douglas Crosher wrote

  Hannu Rummukainen wrote:
  ...
  > There's something weird going on with the compilation of the attached
  > code.  Compiling and loading the file in a fresh lisp, then invoking
  > (test-it) gives
  Thanks for the bug report, nice to have this one fixed. It was a bug
  in the x86 backend, the < VOP. A fix has been committed to the main
  source, see the file compiler/x86/float.lisp.

  Probably the same bug exists in SBCL.

* TYPEP treats the result of UPGRADED-ARRAY-ELEMENT-TYPE as gospel,
  so that (TYPEP (MAKE-ARRAY 3) '(VECTOR SOMETHING-NOT-DEFINED-YET))
  returns (VALUES T T). Probably it should be an error instead,
  complaining that the type SOMETHING-NOT-DEFINED-YET is not defined.

* TYPEP of VALUES types is sometimes implemented very inefficiently, e.g. in 
	(DEFTYPE INDEXOID () '(INTEGER 0 1000))
	(DEFUN FOO (X)
	  (DECLARE (TYPE INDEXOID X))
	  (THE (VALUES INDEXOID)
	    (VALUES X)))
  where the implementation of the type check in function FOO 
  includes a full call to %TYPEP. There are also some fundamental problems
  with the interpretation of VALUES types (inherited from CMU CL, and
  from the ANSI CL standard) as discussed on the cmucl-imp@cons.org
  mailing list, e.g. in Robert Maclachlan's post of 21 Jun 2000.

* The definitions of SIGCONTEXT-FLOAT-REGISTER and
  %SET-SIGCONTEXT-FLOAT-REGISTER in x86-vm.lisp say they're not
  supported on FreeBSD because the floating point state is not saved,
  but at least as of FreeBSD 4.0, the floating point state *is* saved,
  so they could be supported after all. Very likely 
  SIGCONTEXT-FLOATING-POINT-MODES could now be supported, too.

* (as discussed by Douglas Crosher on the cmucl-imp mailing list ca. 
  Aug. 10, 2000): CMUCL currently interprets 'member as '(member); same issue
  with 'union, 'and, 'or etc. So even though according to the ANSI spec,
  bare 'MEMBER, 'AND, and 'OR are not legal types, CMUCL (and now
  SBCL) interpret them as legal types.

* ANSI specifies DEFINE-SYMBOL-MACRO, but it's not defined in SBCL.
  CMU CL added it ca. Aug 13, 2000, after some discussion on the mailing
  list, and it is probably possible to use substantially the same 
  patches to add it to SBCL.

* a slew of floating-point-related errors reported by Peter Van Eynde
  on July 25, 2000:
	* (SQRT -9.0) fails, because SB-KERNEL::COMPLEX-SQRT is undefined.
	  Similarly, COMPLEX-ASIN, COMPLEX-ACOS, COMPLEX-ACOSH, and others
	  aren't found.
	* SBCL's value for LEAST-POSITIVE-SHORT-FLOAT is bogus, and 
	  should probably be 1.4012985e-45. In SBCL,
	  (/ LEAST-POSITIVE-SHORT-FLOAT 2) returns a number smaller
	  than LEAST-POSITIVE-SHORT-FLOAT. Similar problems 
	  exist for LEAST-NEGATIVE-SHORT-FLOAT, LEAST-POSITIVE-LONG-FLOAT,
	  and LEAST-NEGATIVE-LONG-FLOAT.
	* Many expressions generate floating infinity:
		(/ 1 0.0)
		(/ 1 0.0d0)
		(EXPT 10.0 1000)
		(EXPT 10.0d0 1000)
	  PVE's regression tests want them to raise errors. SBCL
	  generates the infinities instead, which may or may not be
	  conforming behavior, but then blow it by being unable to
	  output the infinities, since support for infinities is generally
	  broken, and in particular SB-IMPL::OUTPUT-FLOAT-INFINITY is
	  undefined.
	* (in section12.erg) various forms a la 
	  (FLOAT 1 DOUBLE-FLOAT-EPSILON) don't give the right behavior.

* type safety errors reported by Peter Van Eynde July 25, 2000:
	* (COERCE (QUOTE (A B C)) (QUOTE (VECTOR * 4)))
	  => #(A B C)
	  In general lengths of array type specifications aren't
	  checked by COERCE, so it fails when the spec is
	  (VECTOR 4), (STRING 2), (SIMPLE-BIT-VECTOR 3), or whatever.
	* CONCATENATE has the same problem of not checking the length
	  of specified output array types. MAKE-SEQUENCE and MAP and
	  MERGE also have the same problem.
	* (COERCE 'AND 'FUNCTION) returns something related to
	  (MACRO-FUNCTION 'AND), but ANSI says it should raise an error.
	* ELT signals SIMPLE-ERROR if its index argument
	  isn't a valid index for its sequence argument, but should 
	  signal TYPE-ERROR instead.
	* FILE-LENGTH is supposed to signal a type error when its
	  argument is not a stream associated with a file, but doesn't.
	* (FLOAT-RADIX 2/3) should signal an error instead of 
	  returning 2.
	* (LOAD "*.lsp") should signal FILE-ERROR.
	* (MAKE-CONCATENATED-STREAM (MAKE-STRING-OUTPUT-STREAM))
	  should signal TYPE-ERROR.
	* MAKE-TWO-WAY-STREAM doesn't check that its arguments can
	  be used for input and output as needed. It should fail with
	  TYPE-ERROR when handed e.g. the results of MAKE-STRING-INPUT-STREAM
	  or MAKE-STRING-OUTPUT-STREAM in the inappropriate positions,
	  but doesn't.
	* (PARSE-NAMESTRING (COERCE (LIST #\f #\o #\o (CODE-CHAR 0) #\4 #\8)
			    (QUOTE STRING)))
	  should probably signal an error instead of making a pathname with
	  a null byte in it.
	* READ-BYTE is supposed to signal TYPE-ERROR when its argument is 
	  not a binary input stream, but instead cheerfully reads from
	  character streams, e.g. (MAKE-STRING-INPUT-STREAM "abc").

* DEFCLASS bugs reported by Peter Van Eynde July 25, 2000:
	* (DEFCLASS FOO () (A B A)) should signal a PROGRAM-ERROR, and doesn't.
	* (DEFCLASS FOO () (A B A) (:DEFAULT-INITARGS X A X B)) should
	  signal a PROGRAM-ERROR, and doesn't.
	* (DEFCLASS FOO07 NIL ((A :ALLOCATION :CLASS :ALLOCATION :CLASS))),
	  and other DEFCLASS forms with duplicate specifications in their
	  slots, should signal a PROGRAM-ERROR, and doesn't.
	* (DEFGENERIC IF (X)) should signal a PROGRAM-ERROR, but instead
	  causes a COMPILER-ERROR.

* SYMBOL-MACROLET bugs reported by Peter Van Eynde July 25, 2000:
	* (SYMBOL-MACROLET ((T TRUE)) ..) should probably signal
	  PROGRAM-ERROR, but SBCL accepts it instead.
	* SYMBOL-MACROLET should refuse to bind something which is
	  declared as a global variable, signalling PROGRAM-ERROR.
	* SYMBOL-MACROLET should signal PROGRAM-ERROR if something
	  it binds is declared SPECIAL inside.

* LOOP bugs reported by Peter Van Eynde July 25, 2000:
	* (LOOP WITH (A B) DO (PRINT 1)) is a syntax error according to
	  the definition of WITH clauses given in the ANSI spec, but
	  compiles and runs happily in SBCL.
	* a messy one involving package iteration:
interpreted Form: (LET ((PACKAGE (MAKE-PACKAGE "LOOP-TEST"))) (INTERN "blah" PACKAGE) (LET ((BLAH2 (INTERN "blah2" PACKAGE))) (EXPORT BLAH2 PACKAGE)) (LIST (SORT (LOOP FOR SYM BEING EACH PRESENT-SYMBOL OF PACKAGE FOR SYM-NAME = (SYMBOL-NAME SYM) COLLECT SYM-NAME) (FUNCTION STRING<)) (SORT (LOOP FOR SYM BEING EACH EXTERNAL-SYMBOL OF PACKAGE FOR SYM-NAME = (SYMBOL-NAME SYM) COLLECT SYM-NAME) (FUNCTION STRING<))))
Should be: (("blah" "blah2") ("blah2"))
SBCL: (("blah") ("blah2"))
	* (LET ((X 1)) (LOOP FOR I BY (INCF X) FROM X TO 10 COLLECT I))
	  doesn't work -- SBCL's LOOP says BY isn't allowed in a FOR clause.

* type system errors reported by Peter Van Eynde July 25, 2000:
	* (SUBTYPEP 'BIGNUM 'INTEGER) => NIL, NIL
	  but should be (VALUES T T) instead.
	* (SUBTYPEP 'EXTENDED-CHAR 'CHARACTER) => NIL, NIL
	  but should be (VALUES T T) instead.
	* (SUBTYPEP '(INTEGER (0) (0)) 'NIL) dies with nested errors.
	* In general, the system doesn't like '(INTEGER (0) (0)) -- it
	  blows up at the level of SPECIFIER-TYPE with
	  "Lower bound (0) is greater than upper bound (0)." Probably
	  SPECIFIER-TYPE should return NIL instead.
	* (TYPEP 0 '(COMPLEX (EQL 0)) fails with
	  "Component type for Complex is not numeric: (EQL 0)."
	  This might be easy to fix; the type system already knows
	  that (SUBTYPEP '(EQL 0) 'NUMBER) is true.
	* The type system doesn't know about the condition system,
	  so that e.g. (TYPEP 'SIMPLE-ERROR 'ERROR)=>NIL.
	* The type system isn't all that smart about relationships
	  between hairy types, as shown in the type.erg test results,
	  e.g. (SUBTYPEP 'CONS '(NOT ATOM)) => NIL, NIL.

* miscellaneous errors reported by Peter Van Eynde July 25, 2000:
	* (PROGN
	    (DEFGENERIC FOO02 (X))
	    (DEFMETHOD FOO02 ((X NUMBER)) T)
	    (LET ((M (FIND-METHOD (FUNCTION FOO02)
				  NIL
				  (LIST (FIND-CLASS (QUOTE NUMBER))))))
	      (REMOVE-METHOD (FUNCTION FOO02) M)
	      (DEFGENERIC FOO03 (X))
	      (ADD-METHOD (FUNCTION FOO03) M)))
	   should give an error, but SBCL allows it.
	* READ should probably return READER-ERROR, not the bare 
	  arithmetic error, when input a la "1/0" or "1e1000" causes
	  an arithmetic error.
	* There are several metaobject protocol "errors". (In order to fix
	  them, we might need to document exactly what metaobject
	  protocol specification we're following -- the current code is
	  just inherited from PCL.)
	* (BUTLAST NIL) should return NIL. (This appears to be a compiler
	  bug, since the definition of BUTLAST, when interpreted, does
	  give (BUTLAST NIL)=>NIL.)

* another error from Peter Van Eynde 5 September 2000:
  (FORMAT NIL "~F" "FOO") should work, but instead reports an error.
  PVE submitted a patch to deal with this bug, but it exposes other
  comparably serious bugs, so I didn't apply it. It looks as though
  the FORMAT code needs a fair amount of rewriting in order to comply
  with the various details of the ANSI spec.

* The bug discussed on the cmucl-imp@cons.org mailing list ca. 5 September,
  simplified by Douglas Crosher down to
	(defun tickle-bug ()
	  (labels ((fun1 ()
	             (fun2))
        	   (fun2 ()                             
	             (when nil
        	       (tagbody
                	tag
	                  (fun2)
        	          (go tag)))
	             (when nil
        	       (tagbody
                	tag
	                  (fun1)
        	          (go tag)))))
	    (fun1)
	    nil))
  causes the same problem on SBCL: compiling it fails with 
	:LET fell through ECASE expression.
  Very likely the patch discussed there is appropriate for SBCL
  as well, but I don't understand it, so I didn't apply it.