+341: PPRINT-LOGICAL-BLOCK / PPRINT-FILL / PPRINT-LINEAR sharing detection.
+ (from Paul Dietz' test suite)
+
+ CLHS on PPRINT-LINEAR and PPRINT-FILL (and PPRINT-TABULAR, though
+ that's slightly different) states that these functions perform
+ circular and shared structure detection on their object. Therefore,
+
+ a.(let ((*print-circle* t))
+ (pprint-linear *standard-output* (let ((x '(a))) (list x x))))
+ should print "(#1=(A) #1#)"
+
+ b.(let ((*print-circle* t))
+ (pprint-linear *standard-output*
+ (let ((x (cons nil nil))) (setf (cdr x) x) x)))
+ should print "#1=(NIL . #1#)"
+
+ (it is likely that the fault lies in PPRINT-LOGICAL-BLOCK, as
+ suggested by the suggested implementation of PPRINT-TABULAR)
+
+343: MOP:COMPUTE-DISCRIMINATING-FUNCTION overriding causes error
+ Even the simplest possible overriding of
+ COMPUTE-DISCRIMINATING-FUNCTION, suggested in the PCL implementation
+ as "canonical", does not work:
+ (defclass my-generic-function (standard-generic-function) ()
+ (:metaclass funcallable-standard-class))
+ (defmethod compute-discriminating-function ((gf my-generic-function))
+ (let ((dfun (call-next-method)))
+ (lambda (&rest args)
+ (apply dfun args))))
+ (defgeneric foo (x)
+ (:generic-function-class my-generic-function))
+ (defmethod foo (x) (+ x x))
+ (foo 5)
+ signals an error. This error is the same even if the LAMBDA is
+ replaced by (FUNCTION (SB-KERNEL:INSTANCE-LAMBDA ...)). Maybe the
+ SET-FUNCALLABLE-INSTANCE-FUN scary stuff in
+ src/code/target-defstruct.lisp is broken? This seems to be broken
+ in CMUCL 18e, so it's not caused by a recent change.
+
+344: more (?) ROOM T problems (possibly part of bug 108)
+ In sbcl-0.8.12.51, and off and on leading up to it, the
+ SB!VM:MEMORY-USAGE operations in ROOM T caused
+ unhandled condition (of type SB-INT:BUG):
+ failed AVER: "(SAP= CURRENT END)"
+ Several clever people have taken a shot at this without fixing
+ it; this time around (before sbcl-0.8.13 release) I (WHN) just
+ commented out the SB!VM:MEMORY-USAGE calls until someone figures
+ out how to make them work reliably with the rest of the GC.
+
+ (Note: there's at least one dubious thing in room.lisp: see the
+ comment in VALID-OBJ)
+
+345: backtrace on x86 undefined function
+ In sbcl-0.8.13 (and probably earlier versions), code of the form
+ (flet ((test () (#:undefined-fun 42)))
+ (funcall #'test))
+ yields the debugger with a poorly-functioning backtrace. Brian
+ Downing fixed most of the problems on non-x86 architectures, but on
+ the x86 the backtrace from this evaluation does not reveal anything
+ about the problem. (See tests in debug.impure.lisp)
+
+346: alpha backtrace
+ In sbcl-0.8.13, all backtraces from errors caused by internal errors
+ on the alpha seem to have a "bogus stack frame".
+
+348:
+ Structure slot setters do not preserve evaluation order:
+
+ (defstruct foo (x))
+
+ (let ((i (eval '-2))
+ (x (make-foo)))
+ (funcall #'(setf foo-x)
+ (incf i)
+ (aref (vector x) (incf i)))
+ (foo-x x))
+ => error
+
+349: PPRINT-INDENT rounding implementation decisions
+ At present, pprint-indent (and indeed the whole pretty printer)
+ more-or-less assumes that it's using a monospace font. That's
+ probably not too silly an assumption, but one piece of information
+ the current implementation loses is from requests to indent by a
+ non-integral amount. As of sbcl-0.8.15.9, the system silently
+ truncates the indentation to an integer at the point of request, but
+ maybe the non-integral value should be propagated through the
+ pprinter and only truncated at output? (So that indenting by 1/2
+ then 3/2 would indent by two spaces, not one?)
+
+352: forward-referenced-class trouble
+ reported by Bruno Haible on sbcl-devel
+ (defclass c (a) ())
+ (setf (class-name (find-class 'a)) 'b)
+ (defclass a () (x))
+ (defclass b () (y))
+ (make-instance 'c)
+ Expected: an instance of c, with a slot named x
+ Got: debugger invoked on a SIMPLE-ERROR in thread 78906:
+ While computing the class precedence list of the class named C.
+ The class named B is a forward referenced class.
+ The class named B is a direct superclass of the class named C.