1 files changed, 55 insertions, 10 deletions
diff --git a/test/ruby/test_const.rb b/test/ruby/test_const.rb
index 3708a5a0ca..f6b9ea83d3 100644
--- a/test/ruby/test_const.rb
+++ b/test/ruby/test_const.rb
@@ -1,20 +1,32 @@
+# -*- coding: us-ascii -*-
+# frozen_string_literal: false
 require 'test/unit'
 
 class TestConst < Test::Unit::TestCase
-  TEST1 = 1
-  TEST2 = 2
 
-  module Const
-    TEST3 = 3
-    TEST4 = 4
-  end
+  Constants_Setup = -> do
+    remove_const :TEST1  if defined? ::TestConst::TEST1
+    remove_const :TEST2  if defined? ::TestConst::TEST2
+    remove_const :Const  if defined? ::TestConst::Const
+    remove_const :Const2 if defined? ::TestConst::Const2
+
+    TEST1 = 1
+    TEST2 = 2
 
-  module Const2
-    TEST3 = 6
-    TEST4 = 8
+    module Const
+      TEST3 = 3
+      TEST4 = 4
+    end
+
+    module Const2
+      TEST3 = 6
+      TEST4 = 8
+    end
   end
 
   def test_const
+    Constants_Setup.call
+
     assert defined?(TEST1)
     assert_equal 1, TEST1
     assert defined?(TEST2)
@@ -35,7 +47,7 @@ class TestConst < Test::Unit::TestCase
     self.class.class_eval {
       include Const2
     }
-    STDERR.print "intentionally redefines TEST3, TEST4\n" if $VERBOSE
+    # STDERR.print "intentionally redefines TEST3, TEST4\n" if $VERBOSE
     assert defined?(TEST1)
     assert_equal 1, TEST1
     assert defined?(TEST2)
@@ -45,4 +57,37 @@ class TestConst < Test::Unit::TestCase
     assert defined?(TEST4)
     assert_equal 8, TEST4
   end
+
+  def test_const_access_from_nil
+    assert_raise(TypeError) { eval("nil::Object") }
+    assert_nil eval("defined?(nil::Object)")
+
+    assert_raise(TypeError) { eval("c = nil; c::Object") }
+    assert_nil eval("c = nil; defined?(c::Object)")
+
+    assert_raise(TypeError) { eval("sc = Class.new; sc::C = nil; sc::C::Object") }
+    assert_nil eval("sc = Class.new; sc::C = nil; defined?(sc::C::Object)")
+  end
+
+  def test_redefinition
+    c = Class.new
+    name = "X\u{5b9a 6570}"
+    c.const_set(name, 1)
+    prev_line = __LINE__ - 1
+    assert_warning(<<-WARNING) {c.const_set(name, 2)}
+#{__FILE__}:#{__LINE__-1}: warning: already initialized constant #{c}::#{name}
+#{__FILE__}:#{prev_line}: warning: previous definition of #{name} was here
+WARNING
+  end
+
+  def test_redefinition_memory_leak
+    code = <<-PRE
+350000.times { FOO = :BAR }
+PRE
+    assert_no_memory_leak(%w[-W0 -], '', code, 'redefined constant', timeout: 30)
+  end
+
+  def test_toplevel_lookup
+    assert_raise(NameError, '[Feature #11547]') {TestConst::Object}
+  end
 end