Stop marking chilled strings as frozen

They were initially made frozen to avoid false positives for cases such
as:

    str = str.dup if str.frozen?

But this may cause bugs and is generally confusing for users.

[Feature #20205]

Co-authored-by: Jean Boussier <[email protected]>

2 files changed, 3 insertions, 7 deletions

diff --git a/test/ruby/test_rubyoptions.rb b/test/ruby/test_rubyoptions.rb
index 76be9152a7..d9b98be8ba 100644
--- a/test/ruby/test_rubyoptions.rb
+++ b/test/ruby/test_rubyoptions.rb
@@ -1208,15 +1208,12 @@ class TestRubyOptions < Test::Unit::TestCase
   end
 
   def test_frozen_string_literal_debug
-    default_frozen = eval("'test'").frozen?
-
     with_debug_pat = /created at/
     wo_debug_pat = /can\'t modify frozen String: "\w+" \(FrozenError\)\n\z/
     frozen = [
       ["--enable-frozen-string-literal", true],
       ["--disable-frozen-string-literal", false],
     ]
-    frozen << [nil, false] unless default_frozen
 
     debugs = [
       ["--debug-frozen-string-literal", true],
diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index ebe85dac82..9bd86dfb78 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -3617,17 +3617,16 @@ CODE
   def test_chilled_string
     chilled_string = eval('"chilled"')
 
-    # Chilled strings pretend to be frozen
-    assert_predicate chilled_string, :frozen?
+    assert_not_predicate chilled_string, :frozen?
 
     assert_not_predicate chilled_string.dup, :frozen?
-    assert_predicate chilled_string.clone, :frozen?
+    assert_not_predicate chilled_string.clone, :frozen?
 
     # @+ treat the original string as frozen
     assert_not_predicate(+chilled_string, :frozen?)
     assert_not_same chilled_string, +chilled_string
 
-    # @- the original string as mutable
+    # @- treat the original string as mutable
     assert_predicate(-chilled_string, :frozen?)
     assert_not_same chilled_string, -chilled_string
   end