2 files changed, 80 insertions, 8 deletions
diff --git a/spec/ruby/core/kernel/eval_spec.rb b/spec/ruby/core/kernel/eval_spec.rb
index 15c9d511fc..5d82f57e44 100644
--- a/spec/ruby/core/kernel/eval_spec.rb
+++ b/spec/ruby/core/kernel/eval_spec.rb
@@ -350,9 +350,11 @@ CODE
     end
 
     it "allows a magic encoding comment and a subsequent frozen_string_literal magic comment" do
+      frozen_string_default = "test".frozen?
+
       code = <<CODE.b
 # encoding: UTF-8
-# frozen_string_literal: true
+# frozen_string_literal: #{!frozen_string_default}
 class EvalSpecs
   Vπstring = "frozen"
 end
@@ -362,7 +364,7 @@ CODE
       EvalSpecs.constants(false).should include(:"Vπstring")
       EvalSpecs::Vπstring.should == "frozen"
       EvalSpecs::Vπstring.encoding.should == Encoding::UTF_8
-      EvalSpecs::Vπstring.frozen?.should be_true
+      EvalSpecs::Vπstring.frozen?.should == !frozen_string_default
     end
 
     it "allows a magic encoding comment and a frozen_string_literal magic comment on the same line in emacs style" do
@@ -381,8 +383,9 @@ CODE
     end
 
     it "ignores the magic encoding comment if it is after a frozen_string_literal magic comment" do
+      frozen_string_default = "test".frozen?
       code = <<CODE.b
-# frozen_string_literal: true
+# frozen_string_literal: #{!frozen_string_default}
 # encoding: UTF-8
 class EvalSpecs
   Vπfrozen_first = "frozen"
@@ -396,24 +399,24 @@ CODE
       value = EvalSpecs.const_get(binary_constant)
       value.should == "frozen"
       value.encoding.should == Encoding::BINARY
-      value.frozen?.should be_true
+      value.frozen?.should == !frozen_string_default
     end
 
     it "ignores the frozen_string_literal magic comment if it appears after a token and warns if $VERBOSE is true" do
-      default_frozen_string_literal = "test".frozen?
+      frozen_string_default = "test".frozen?
       code = <<CODE
 some_token_before_magic_comment = :anything
-# frozen_string_literal: true
+# frozen_string_literal: #{!frozen_string_default}
 class EvalSpecs
   Vπstring_not_frozen = "not frozen"
 end
 CODE
       -> { eval(code) }.should complain(/warning: [`']frozen_string_literal' is ignored after any tokens/, verbose: true)
-      EvalSpecs::Vπstring_not_frozen.frozen?.should == default_frozen_string_literal
+      EvalSpecs::Vπstring_not_frozen.frozen?.should == frozen_string_default
       EvalSpecs.send :remove_const, :Vπstring_not_frozen
 
       -> { eval(code) }.should_not complain(verbose: false)
-      EvalSpecs::Vπstring_not_frozen.frozen?.should == default_frozen_string_literal
+      EvalSpecs::Vπstring_not_frozen.frozen?.should == frozen_string_default
       EvalSpecs.send :remove_const, :Vπstring_not_frozen
     end
   end
diff --git a/spec/ruby/core/string/chilled_string_spec.rb b/spec/ruby/core/string/chilled_string_spec.rb
new file mode 100644
index 0000000000..8de4fc421b
--- /dev/null
+++ b/spec/ruby/core/string/chilled_string_spec.rb
@@ -0,0 +1,69 @@
+require_relative '../../spec_helper'
+
+describe "chilled String" do
+  guard -> { ruby_version_is "3.4" and !"test".equal?("test") } do
+    describe "#frozen?" do
+      it "returns true" do
+        "chilled".frozen?.should == true
+      end
+    end
+
+    describe "#-@" do
+      it "returns a different instance" do
+        input = "chilled"
+        interned = (-input)
+        interned.frozen?.should == true
+        interned.object_id.should_not == input.object_id
+      end
+    end
+
+    describe "#+@" do
+      it "returns a different instance" do
+        input = "chilled"
+        duped = (+input)
+        duped.frozen?.should == false
+        duped.object_id.should_not == input.object_id
+      end
+    end
+
+    describe "#clone" do
+      it "preserves chilled status" do
+        input = "chilled".clone
+        -> {
+          input << "-mutated"
+        }.should complain(/literal string will be frozen in the future/)
+        input.should == "chilled-mutated"
+      end
+    end
+
+    describe "mutation" do
+      it "emits a warning" do
+        input = "chilled"
+        -> {
+          input << "-mutated"
+        }.should complain(/literal string will be frozen in the future/)
+        input.should == "chilled-mutated"
+      end
+
+      it "emits a warning on singleton_class creaation" do
+        -> {
+          "chilled".singleton_class
+        }.should complain(/literal string will be frozen in the future/)
+      end
+
+      it "emits a warning on instance variable assignment" do
+        -> {
+          "chilled".instance_variable_set(:@ivar, 42)
+        }.should complain(/literal string will be frozen in the future/)
+      end
+
+      it "raises FrozenError after the string was explictly frozen" do
+        input = "chilled"
+        input.freeze
+        -> {
+          input << "mutated"
+        }.should raise_error(FrozenError)
+      end
+    end
+  end
+end