Hi! Thank you, Mark! That looks great.
I note also that this is fixed in master, unless I made another bug. See type-fold.scm:66-87 and types.scm:574-617. Cheers! Andy On Sun 14 Oct 2018 06:05, Mark H Weaver <m...@netris.org> writes: > Mark H Weaver <m...@netris.org> writes: > >> calcium <calc...@disroot.org> writes: >>> Here is the bug that I found : >>> >>> ;;; -START- code with the bug -START- ;;; >>> >>> (define (strange lst) >>> (let loop ((lst lst) >>> (is-empty '())) >>> (cond ((nil? lst) >>> (if (nil? is-empty) 'works >>> (list 'should-not-occur is-empty))) >>> (else >>> (loop (cdr lst) >>> is-empty))))) >>> >>> (strange '()) >>> => (should-not-occur ()) >>> >>> (strange #nil) >>> => (should-not-occur ()) >> >> Indeed, this certainly indicates a bug. >> >> I believe the bug is in 'local-type-fold' in (language cps type-fold). >> It contains a local procedure 'scalar-value' which, if I understand >> correctly, seems to incorrectly assume that (nil? x) returns #t if and >> only if X is 'eq?' to #nil. > > The bug actually wasn't in 'local-type-fold', but it's true that the > type inferencer assumed in a few places that if (nil? X) returned #t > that X must be #nil, and similarly for 'null?' and (). > > I've attached a proposed fix. > > Andy, does this fix look right to you? > > Thanks, > Mark > > > From d904d5233582e51a4be06d2c08ccdd15a66b8d77 Mon Sep 17 00:00:00 2001 > From: Mark H Weaver <m...@netris.org> > Date: Sat, 13 Oct 2018 23:02:05 -0400 > Subject: [PATCH] Fix type inferencing for 'nil?' and 'null?' predicates. > > Fixes <https://bugs.gnu.org/33036>. > Reported by <calc...@disroot.org>. > > * module/language/cps/types.scm (define-simple-type-inferrer): > Apply (logand (&type val) <>) uniformly. Previously, this was done only > in the false branch. Rename local variable to 'type*', to allow the > macro operand 'type' to be an arbitrary expression. > (*type-inferrers*)<null?>: Add &nil to the set of possible types. > (*type-inferrers*)<nil?>: Add &false and &null to the set the possible > types. > * module/language/cps/type-fold.scm (*branch-folders*)<null?>: Add &nil > to the set of possible types. > (*branch-folders*)<nil?>: Add &false and &null to the set the possible > types. > * test-suite/tests/compiler.test: Add tests. > --- > module/language/cps/type-fold.scm | 6 ++-- > module/language/cps/types.scm | 13 ++++---- > test-suite/tests/compiler.test | 51 ++++++++++++++++++++++++++++++- > 3 files changed, 60 insertions(+), 10 deletions(-) > > diff --git a/module/language/cps/type-fold.scm > b/module/language/cps/type-fold.scm > index fc37fac50..163ef659d 100644 > --- a/module/language/cps/type-fold.scm > +++ b/module/language/cps/type-fold.scm > @@ -1,5 +1,5 @@ > ;;; Abstract constant folding on CPS > -;;; Copyright (C) 2014, 2015 Free Software Foundation, Inc. > +;;; Copyright (C) 2014, 2015, 2018 Free Software Foundation, Inc. > ;;; > ;;; This library is free software: you can redistribute it and/or modify > ;;; it under the terms of the GNU Lesser General Public License as > @@ -69,8 +69,8 @@ > > ;; All the cases that are in compile-bytecode. > (define-unary-type-predicate-folder pair? &pair) > -(define-unary-type-predicate-folder null? &null) > -(define-unary-type-predicate-folder nil? &nil) > +(define-unary-type-predicate-folder null? (logior &nil &null)) > +(define-unary-type-predicate-folder nil? (logior &false &nil &null)) > (define-unary-type-predicate-folder symbol? &symbol) > (define-unary-type-predicate-folder variable? &box) > (define-unary-type-predicate-folder vector? &vector) > diff --git a/module/language/cps/types.scm b/module/language/cps/types.scm > index 5c1d71299..61de971fe 100644 > --- a/module/language/cps/types.scm > +++ b/module/language/cps/types.scm > @@ -529,13 +529,14 @@ minimum, and maximum." > > (define-syntax-rule (define-simple-predicate-inferrer predicate type) > (define-predicate-inferrer (predicate val true?) > - (let ((type (if true? > - type > - (logand (&type val) (lognot type))))) > - (restrict! val type -inf.0 +inf.0)))) > + (let ((type* (logand (&type val) > + (if true? > + type > + (lognot type))))) > + (restrict! val type* -inf.0 +inf.0)))) > (define-simple-predicate-inferrer pair? &pair) > -(define-simple-predicate-inferrer null? &null) > -(define-simple-predicate-inferrer nil? &nil) > +(define-simple-predicate-inferrer null? (logior &nil &null)) > +(define-simple-predicate-inferrer nil? (logior &false &nil &null)) > (define-simple-predicate-inferrer symbol? &symbol) > (define-simple-predicate-inferrer variable? &box) > (define-simple-predicate-inferrer vector? &vector) > diff --git a/test-suite/tests/compiler.test b/test-suite/tests/compiler.test > index 4f644f339..64bb976fa 100644 > --- a/test-suite/tests/compiler.test > +++ b/test-suite/tests/compiler.test > @@ -1,5 +1,5 @@ > ;;;; compiler.test --- tests for the compiler -*- scheme -*- > -;;;; Copyright (C) 2008, 2009, 2010, 2011, 2012, 2013, 2014 Free Software > Foundation, Inc. > +;;;; Copyright (C) 2008-2014, 2018 Free Software Foundation, Inc. > ;;;; > ;;;; This library is free software; you can redistribute it and/or > ;;;; modify it under the terms of the GNU Lesser General Public > @@ -251,3 +251,52 @@ > > (pass-if-equal "test flonum" 0.0 (test-proc #t)) > (pass-if-equal "test complex" 0.0+0.0i (test-proc #f))) > + > +(with-test-prefix "null? and nil? inference" > + (pass-if-equal "nil? after null?" > + '((f . f) ; 3 > + (f . f) ; #t > + (f . t) ; #f > + (t . t) ; #nil > + (t . t)) ; () > + (map (compile '(lambda (x) > + (if (null? x) > + (cons 't (if (nil? x) 't 'f)) > + (cons 'f (if (nil? x) 't 'f))))) > + '(3 #t #f #nil ()))) > + > + (pass-if-equal "nil? after truth test" > + '((t . f) ; 3 > + (t . f) ; #t > + (f . t) ; #f > + (f . t) ; #nil > + (t . t)) ; () > + (map (compile '(lambda (x) > + (if x > + (cons 't (if (nil? x) 't 'f)) > + (cons 'f (if (nil? x) 't 'f))))) > + '(3 #t #f #nil ()))) > + > + (pass-if-equal "null? after nil?" > + '((f . f) ; 3 > + (f . f) ; #t > + (t . f) ; #f > + (t . t) ; #nil > + (t . t)) ; () > + (map (compile '(lambda (x) > + (if (nil? x) > + (cons 't (if (null? x) 't 'f)) > + (cons 'f (if (null? x) 't 'f))))) > + '(3 #t #f #nil ()))) > + > + (pass-if-equal "truth test after nil?" > + '((f . t) ; 3 > + (f . t) ; #t > + (t . f) ; #f > + (t . f) ; #nil > + (t . t)) ; () > + (map (compile '(lambda (x) > + (if (nil? x) > + (cons 't (if x 't 'f)) > + (cons 'f (if x 't 'f))))) > + '(3 #t #f #nil ()))))
