1 files changed, 5 insertions, 7 deletions
diff --git a/spec/ruby/core/matchdata/post_match_spec.rb b/spec/ruby/core/matchdata/post_match_spec.rb
index d3aa4c8900..7bfe6df119 100644
--- a/spec/ruby/core/matchdata/post_match_spec.rb
+++ b/spec/ruby/core/matchdata/post_match_spec.rb
@@ -8,19 +8,17 @@ describe "MatchData#post_match" do
   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
 
-  ruby_version_is "3.0" do
-    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
+  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