2 files changed, 73 insertions, 1 deletions
diff --git a/test/ruby/test_hash.rb b/test/ruby/test_hash.rb
index 040d25e144..798bd2fe60 100644
--- a/test/ruby/test_hash.rb
+++ b/test/ruby/test_hash.rb
@@ -133,6 +133,50 @@ class TestHash < Test::Unit::TestCase
     assert_equal(100, h['a'])
     assert_equal(200, h['b'])
     assert_nil(h['c'])
+
+    h = @cls["a", 100, "b", 200]
+    assert_equal(100, h['a'])
+    assert_equal(200, h['b'])
+    assert_nil(h['c'])
+
+    h = @cls[[["a", 100], ["b", 200]]]
+    assert_equal(100, h['a'])
+    assert_equal(200, h['b'])
+    assert_nil(h['c'])
+
+    h = @cls[[["a", 100], ["b"], ["c", 300]]]
+    assert_equal(100, h['a'])
+    assert_equal(nil, h['b'])
+    assert_equal(300, h['c'])
+
+    h = @cls[[["a", 100], "b", ["c", 300]]]
+    assert_equal(100, h['a'])
+    assert_equal(nil, h['b'])
+    assert_equal(300, h['c'])
+  end
+
+  def test_s_AREF_duplicated_key
+    alist = [["a", 100], ["b", 200], ["a", 300], ["a", 400]]
+    h = @cls[alist]
+    assert_equal(2, h.size)
+    assert_equal(400, h['a'])
+    assert_equal(200, h['b'])
+    assert_nil(h['c'])
+    assert_equal(nil, h.key('300'))
+  end
+
+  def test_s_AREF_frozen_key_id
+    key = "a".freeze
+    h = @cls[key, 100]
+    assert_equal(100, h['a'])
+    assert_same(key, *h.keys)
+  end
+
+  def test_s_AREF_key_tampering
+    key = "a".dup
+    h = @cls[key, 100]
+    key.upcase!
+    assert_equal(100, h['a'])
   end
 
   def test_s_new
@@ -145,7 +189,6 @@ class TestHash < Test::Unit::TestCase
     assert_instance_of(@cls, h)
     assert_equal('default', h.default)
     assert_equal('default', h['spurious'])
-
   end
 
   def test_try_convert
diff --git a/test/ruby/test_literal.rb b/test/ruby/test_literal.rb
index 28290fb19d..4a447d59fc 100644
--- a/test/ruby/test_literal.rb
+++ b/test/ruby/test_literal.rb
@@ -394,6 +394,35 @@ class TestRubyLiteral < Test::Unit::TestCase
     end;
   end
 
+  def test_hash_duplicated_key
+    h = EnvUtil.suppress_warning do
+      eval <<~end
+        # This is a syntax that renders warning at very early stage.
+        # eval used to delay warning, to be suppressible by EnvUtil.
+        {"a" => 100, "b" => 200, "a" => 300, "a" => 400}
+      end
+    end
+    assert_equal(2, h.size)
+    assert_equal(400, h['a'])
+    assert_equal(200, h['b'])
+    assert_nil(h['c'])
+    assert_equal(nil, h.key('300'))
+  end
+
+  def test_hash_frozen_key_id
+    key = "a".freeze
+    h = {key => 100}
+    assert_equal(100, h['a'])
+    assert_same(key, *h.keys)
+  end
+
+  def test_hash_key_tampering
+    key = "a"
+    h = {key => 100}
+    key.upcase!
+    assert_equal(100, h['a'])
+  end
+
   def test_range
     assert_instance_of Range, (1..2)
     assert_equal(1..2, 1..2)