0.7.9.53:

[sbcl.git] / BUGS

diff --git a/BUGS b/BUGS
index 7b6595f..3a0c0bf 100644 (file)
--- a/BUGS
+++ b/BUGS
@@ -522,6 +522,40 @@ WORKAROUND:
     internal error, failed AVER:
       "(COMMON-LISP:EQ (SB!C::TN-ENVIRONMENT SB!C:TN) SB!C::TN-ENV)"
 
+  This examples better illustrates the problem:
+
+  (defun tst ()
+    (declare (optimize (speed 2) (debug 3)))
+    (flet ((m1 ()
+             (bar (if (foo) 1 2))
+             (let ((x (foo)))
+               (bar x (list x)))))
+      (if (catch nil)
+          (m1)
+          (m1))))
+
+  (X is allocated in the physical environment of M1; X is :WRITE in
+  the call of LET [convert-to-global]; IF makes sure that a block
+  exists in M1 before this call.)
+
+  Because X is :DEBUG-ENVIRONMENT, it is :LIVE by default in all
+  blocks in the environment, particularly it is :LIVE in the start of
+  M1 (where it is not yet :WRITE) [setup-environment-tn-conflicts].
+
+  Then :LIVE is propagated backwards, i.e. into the caller of M1
+  where X does not exist [lifetime-flow-analysis].
+
+  (CATCH NIL) causes all TNs to be saved; Python fails on saving
+  non-existent variable; if it is replaced with (FOO), the problem
+  appears when debugging TST: LIST-LOCALS says
+
+    debugger invoked on condition of type SB-DI:UNKNOWN-DEBUG-VAR:
+
+    #<SB-DI::COMPILED-DEBUG-VAR X 0
+      {905FF7D}> is not in #<SB-DI::COMPILED-DEBUG-FUNCTION TST>.
+
+  (in those old versions, in which debugger worked :-().
+
 117:
   When the compiler inline expands functions, it may be that different
   kinds of return values are generated from different code branches.
@@ -979,25 +1013,6 @@ WORKAROUND:
 
      (see bug 203)
 
-193: "unhelpful CLOS error reporting when the primary method is missing"
-  In sbcl-0.7.7, when
-    (defmethod foo :before ((x t)) (print x))
-  is the only method defined on FOO, the error reporting when e.g.
-    (foo 12)
-  is relatively unhelpful:
-    There is no primary method for the generic function
-      #<STANDARD-GENERIC-FUNCTION FOO (1)>.
-  with the offending argument nowhere visible in the backtrace. This 
-  continues even if there *are* primary methods, just not for the 
-  specified arg type, e.g. 
-    (defmethod foo ((x character)) (print x))
-    (defmethod foo ((x string)) (print x))
-    (defmethod foo ((x pathname)) ...)
-  In that case it could be very helpful to know what argument value is
-  falling through the cracks of the defined primary methods, but the
-  error message stays the same (even BACKTRACE doesn't tell you what the
-  bad argument value is).
-
 194: "no error from (THE REAL '(1 2 3)) in some cases"
   fixed parts:
     a. In sbcl-0.7.7.9, 
@@ -1314,6 +1329,7 @@ WORKAROUND:
   (fixed in 0.7.9.42)
 
 226: "AVER failure in COMPILE-FILE of clocc-ansi-test/tests.lisp"
+  (APD points out that this seems to be another symptom of bug #115.)
   sbcl-0.7.9.43 dies with failed AVER "(EQ (TN-PHYSENV TN) TN-ENV)" when
   trying to compile clocc-ansi-test/tests.lisp. sbcl-0.7.9.31 was able to
   to compile it. A smaller test case exhibiting the same problem is