Raise `NoMatchingPatternError` when expr `in` pat doesn't match

* `expr in pattern` should raise `NoMatchingError` when unmatched
* `expr in pattern` should return `nil`. (this is unspecified, but
  this feature is experimental, at all)

[Feature #16355]

1 files changed, 4 insertions, 1 deletions

diff --git a/test/ruby/test_pattern_matching.rb b/test/ruby/test_pattern_matching.rb
index 889f8dd519..50bab51bfa 100644
--- a/test/ruby/test_pattern_matching.rb
+++ b/test/ruby/test_pattern_matching.rb
@@ -1261,8 +1261,11 @@ END
   ################################################################
 
   def test_modifier_in
-    assert_equal true, (1 in a)
+    assert_nil (1 in a)
     assert_equal 1, a
+    assert_raise(NoMatchingPatternError) do
+      {a: 1} in {a: 0}
+    end
     assert_valid_syntax "p(({} in {a:}), a:\n 1)"
     assert_syntax_error(%q{
       1 in a, b