From 85aabef023e1a2e81c308ad98741137c73d4d80b Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Mon, 31 Aug 2020 22:13:34 +0900
Subject: [PATCH] [Feature #17136] Remove special behavior from $KCODE

---
 re.c                     | 15 ---------------
 test/ruby/test_regexp.rb | 10 ----------
 2 files changed, 25 deletions(-)

diff --git a/re.c b/re.c
index 55b39bfdea..2af617ea81 100644
--- a/re.c
+++ b/re.c
@@ -3919,19 +3919,6 @@ rb_reg_regsub(VALUE str, VALUE src, struct re_registers *regs, VALUE regexp)
     return val;
 }
 
-static VALUE
-kcode_getter(ID _x, VALUE *_y)
-{
-    rb_warn("variable $KCODE is no longer effective");
-    return Qnil;
-}
-
-static void
-kcode_setter(VALUE val, ID id, VALUE *_)
-{
-    rb_warn("variable $KCODE is no longer effective; ignored");
-}
-
 static VALUE
 ignorecase_getter(ID _x, VALUE *_y)
 {
@@ -4062,8 +4049,6 @@ Init_Regexp(void)
     rb_gvar_ractor_local("$+");
 
     rb_define_virtual_variable("$=", ignorecase_getter, ignorecase_setter);
-    rb_define_virtual_variable("$KCODE", kcode_getter, kcode_setter);
-    rb_define_virtual_variable("$-K", kcode_getter, kcode_setter);
 
     rb_cRegexp = rb_define_class("Regexp", rb_cObject);
     rb_define_alloc_func(rb_cRegexp, rb_reg_s_alloc);
diff --git a/test/ruby/test_regexp.rb b/test/ruby/test_regexp.rb
index 6243ead1ff..e124fc7952 100644
--- a/test/ruby/test_regexp.rb
+++ b/test/ruby/test_regexp.rb
@@ -661,21 +661,11 @@ class TestRegexp < Test::Unit::TestCase
     assert_equal('foobazquux/foobazquux', result, bug8856)
   end
 
-  def test_KCODE
-    assert_nil($KCODE)
-    assert_nothing_raised { $KCODE = nil }
-  end
-
   def test_ignorecase
     assert_equal(false, $=)
     assert_nothing_raised { $= = nil }
   end
 
-  def test_KCODE_warning
-    assert_warning(/variable \$KCODE is no longer effective; ignored/) { $KCODE = nil }
-    assert_warning(/variable \$KCODE is no longer effective/) { $KCODE = nil }
-  end
-
   def test_ignorecase_warning
     assert_warning(/variable \$= is no longer effective; ignored/) { $= = nil }
     assert_warning(/variable \$= is no longer effective/) { $= }