1 files changed, 8 insertions, 20 deletions
diff --git a/spec/ruby/core/matchdata/post_match_spec.rb b/spec/ruby/core/matchdata/post_match_spec.rb
index 4ae51f107e..7bfe6df119 100644
--- a/spec/ruby/core/matchdata/post_match_spec.rb
+++ b/spec/ruby/core/matchdata/post_match_spec.rb
@@ -1,4 +1,5 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "MatchData#post_match" do
   it "returns the string after the match equiv. special var $'" do
@@ -6,31 +7,18 @@ describe "MatchData#post_match" do
     $'.should == ': The Movie'
   end
 
-  ruby_version_is ''...'2.7' do
-    it "keeps taint status from the source string" do
-      str = "THX1138: The Movie"
-      str.taint
-      res = /(.)(.)(\d+)(\d)/.match(str).post_match
-      res.tainted?.should be_true
-      $'.tainted?.should be_true
-    end
-
-    it "keeps untrusted status from the source string" do
-      str = "THX1138: The Movie"
-      str.untrust
-      res = /(.)(.)(\d+)(\d)/.match(str).post_match
-      res.untrusted?.should be_true
-      $'.untrusted?.should be_true
-    end
-  end
-
   it "sets the encoding to the encoding of the source String" do
-    str = "abc".force_encoding Encoding::EUC_JP
+    str = "abc".dup.force_encoding Encoding::EUC_JP
     str.match(/b/).post_match.encoding.should equal(Encoding::EUC_JP)
   end
 
   it "sets an empty result to the encoding of the source String" do
-    str = "abc".force_encoding Encoding::ISO_8859_1
+    str = "abc".dup.force_encoding Encoding::ISO_8859_1
     str.match(/c/).post_match.encoding.should equal(Encoding::ISO_8859_1)
   end
+
+  it "returns an instance of String when given a String subclass" do
+    str = MatchDataSpecs::MyString.new("THX1138: The Movie")
+    /(.)(.)(\d+)(\d)/.match(str).post_match.should be_an_instance_of(String)
+  end
 end