is attached to FOO in 120a above, and used to optimize code which
calls FOO.
+122:
+ There was some sort of screwup in handling of
+ (IF (NOT (IGNORE-ERRORS ..))). E.g.
+ (defun foo1i ()
+ (if (not (ignore-errors
+ (make-pathname :host "foo" :directory "!bla" :name "bar")))
+ (print "ok")
+ (error "notunlessnot")))
+ The (NOT (IGNORE-ERRORS ..)) form evaluates to T, so this should be
+ printing "ok", but instead it's going to the ERROR. This problem
+ seems to've been introduced by MNA's HANDLER-CASE patch (sbcl-devel
+ 2001-07-17) and as a workaround (put in sbcl-0.pre7.14.flaky4.12)
+ I reverted back to the old weird HANDLER-CASE code. However, I
+ think the problem looks like a compiler bug in handling RETURN-FROM,
+ so I left the MNA-patched code in HANDLER-CASE (suppressed with
+ #+NIL) and I'd like to go back to see whether this really is
+ a compiler bug before I delete this BUGS entry.
+
+123:
+ The *USE-IMPLEMENTATION-TYPES* hack causes bugs, particularly
+ (IN-PACKAGE :SB-KERNEL)
+ (TYPE= (SPECIFIER-TYPE '(VECTOR T))
+ (SPECIFIER-TYPE '(VECTOR UNDEFTYPE)))
+ Then because of this, the compiler bogusly optimizes
+ (TYPEP #(11) '(SIMPLE-ARRAY UNDEF-TYPE 1))
+ to T. Unfortunately, just setting *USE-IMPLEMENTATION-TYPES* to
+ NIL around sbcl-0.pre7.14.flaky4.12 didn't work: the compiler complained
+ about type mismatches (probably harmlessly, another instance of bug 117);
+ and then cold init died with a segmentation fault.
+
+124:
+ As of version 0.pre7.14, SBCL's implementation of MACROLET makes
+ the entire lexical environment at the point of MACROLET available
+ in the bodies of the macroexpander functions. In particular, it
+ allows the function bodies (which run at compile time) to try to
+ access lexical variables (which are only defined at runtime).
+ It doesn't even issue a warning, which is bad.
+
+ The SBCL behavior arguably conforms to the ANSI spec (since the
+ spec says that the behavior is undefined, ergo anything conforms).
+ However, it would be better to issue a compile-time error.
+ Unfortunately I (WHN) don't see any simple way to detect this
+ condition in order to issue such an error, so for the meantime
+ SBCL just does this weird broken "conforming" thing.
+
+ The ANSI standard says, in the definition of the special operator
+ MACROLET,
+ The macro-expansion functions defined by MACROLET are defined
+ in the lexical environment in which the MACROLET form appears.
+ Declarations and MACROLET and SYMBOL-MACROLET definitions affect
+ the local macro definitions in a MACROLET, but the consequences
+ are undefined if the local macro definitions reference any
+ local variable or function bindings that are visible in that
+ lexical environment.
+ Then it seems to contradict itself by giving the example
+ (defun foo (x flag)
+ (macrolet ((fudge (z)
+ ;The parameters x and flag are not accessible
+ ; at this point; a reference to flag would be to
+ ; the global variable of that name.
+ ` (if flag (* ,z ,z) ,z)))
+ ;The parameters x and flag are accessible here.
+ (+ x
+ (fudge x)
+ (fudge (+ x 1)))))
+ The comment "a reference to flag would be to the global variable
+ of the same name" sounds like good behavior for the system to have.
+ but actual specification quoted above says that the actual behavior
+ is undefined.
+
KNOWN BUGS RELATED TO THE IR1 INTERPRETER
(Note: At some point, the pure interpreter (actually a semi-pure
projects / sbcl.git / blobdiff