From ef239fb96066c558fd8965dce8ab923162f5519e Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Mon, 17 Jul 2023 20:13:15 -0700
Subject: Bug exposed due to to environment changes.

There was a bug in rt_defun in that it was not calling
vm_invalidate_binding. This mean that compiled functions
were not picking up redefinitions. This bug is fixed now
because rt_defun now calls sethash on the top_fb directly,
which modifies the existing binding cell; it is not
allocating a new cell.

We put in new test cases to confirm the proper redefinition
behaviors.

The proper redefinition behavior exposes an issue in
pattern matching.

* tests/019/redef.tl: New file.

* stdlib/match.tl (transform-quote): This function's compiled
image, when deposited into a .tlo file, becomes incorrect
because (sys:hash-lit) turns into #H() syntax, which reads
back as something else. In other words (sys:hash-lit)
deosn't have print-read consistency and so doesn't
externalize.  To fix this right we would need a print mode
which ensures machine readability rather than human
readability, like in Common Lisp. For now, we just break up
the pattern so that it's not a literal match.  This bug was
hidden due to theredefinition issue. When match.tl is
being compiled, it defines non-triv-pat-p twice. Due to
redefinitions not kicking in properly, the first definition
of non-triv-pat-p remains in effect for some functions.
When transform-qquote is being expanded, the (sys:hash-lit)
pattern is treated as non-trivial, even though it is
is trivial, and so it is turned into pattern matching code.
The code doesn't contain a (sys:hash-lit) literal and so
the issue doesn't occur.
---
 stdlib/match.tl    |  2 +-
 tests/019/redef.tl | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 tests/019/redef.tl

diff --git a/stdlib/match.tl b/stdlib/match.tl
index fb11aa4f..149ea71f 100644
--- a/stdlib/match.tl
+++ b/stdlib/match.tl
@@ -1088,7 +1088,7 @@
     ((sys:hash-lit nil . @(all (@key @val)))
      ^@(hash ,*(zip [mapcar transform-qquote key]
                     [mapcar transform-qquote val])))
-    ((sys:hash-lit)
+    ((sys:hash-lit . @(eq nil))
      '@(hash))
     ((sys:struct-lit @type . @args)
      ^@(struct ,(transform-qquote type)
diff --git a/tests/019/redef.tl b/tests/019/redef.tl
new file mode 100644
index 00000000..036fb8c9
--- /dev/null
+++ b/tests/019/redef.tl
@@ -0,0 +1,19 @@
+(load "../common")
+
+(defun foo () :foo)
+
+(defvar foov :foov)
+
+(defun bar () (list (foo) foov))
+
+(compile 'bar)
+
+(test (bar) (:foo :foov))
+
+(defun foo () :bar)
+
+(makunbound 'foov)
+
+(defparml foov :barv)
+
+(test (bar) (:bar :barv))
-- 
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