Forum: Ruby-core [ruby-trunk - Bug #7671][Open] Unexpected result of the Flip-Flop

Issue #7671 has been reported by phasis68 (Heesob Park).

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Bug #7671: Unexpected result of the Flip-Flop
https://bugs.ruby-lang.org/issues/7671

Author: phasis68 (Heesob Park)
Status: Open
Priority: Normal
Assignee:
Category:
Target version:
ruby -v: ruby 2.0.0dev (2013-01-06 trunk 38715) [i386-mswin32_100]


Reported from 
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/...

C:\work>irb
irb(main):001:0> vs = (1..9).to_a
=> [1, 2, 3, 4, 5, 6, 7, 8, 9]
irb(main):002:0> v1 = vs.select { |n| if n==3..n==6 then 1 end }
=> [3, 4, 5, 6]
irb(main):003:0> v2 = vs.select { |n| if n==2..n==16 then 1 end }
=> [2, 3, 4, 5, 6, 7, 8, 9]
irb(main):004:0> v3 = vs.select { |n| if n==3..n==6 then 1 end }
=> [1, 2, 3, 4, 5, 6]

v1 and v3 use some condition , return value is different.

This bug is due to changeset r38292 and only occurs on the irb session.

Here is a patch:
diff --git a/compile.c b/compile.c.new
index db060e7..e644390 100644
--- a/compile.c
+++ b/compile.c.new
@@ -5057,7 +5057,7 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR 
*ret, NODE * node, int poped)

   if (!data) data = iseq->compile_data;
   cnt = data->flip_cnt++ + DEFAULT_SPECIAL_VAR_COUNT;
-  key = INT2FIX(cnt);
+  key = LL2NUM(cnt+(VALUE)iseq);

   ADD_INSN2(ret, nd_line(node), getspecial, key, INT2FIX(0));
   ADD_INSNL(ret, nd_line(node), branchif, lend);