cdhash_cmp: can take rational literals

Rational literals are those integers suffixed with `r`.  They tend to
be a part of more complex expressions like `123/456r`, but in theory
they can live alone.  When such "bare" rational literals are passed to
case-when branch, we have to take care of them.  Fixes [Bug #17854]

1 files changed, 7 insertions, 0 deletions

diff --git a/test/ruby/test_rational.rb b/test/ruby/test_rational.rb
index fe9de64c4c..d7f4961214 100644
--- a/test/ruby/test_rational.rb
+++ b/test/ruby/test_rational.rb
@@ -830,6 +830,13 @@ class Rational_Test < Test::Unit::TestCase
     assert_raise(ZeroDivisionError) {Rational("1/0")}
   end
 
+  def test_cdhash
+    assert_separately([], <<-RUBY)
+      n = case 1 when 2r then false else true end
+      assert_equal(n, true, '[ruby-core:103759] [Bug #17854]')
+    RUBY
+  end
+
   def test_Rational_with_invalid_exception
     assert_raise(ArgumentError) {
       Rational("1/1", exception: 1)