Include inspect value of object in FrozenError messages

FrozenError#receiver was added recently for getting the related
object programmatically.  However, there are cases where FrozenError
is raised and not handled, and in those cases the resulting error
messages lack detail, which makes debugging the error more difficult,
especially in cases where the error is not easily reproducible.
This includes the inspect value of the frozen object in FrozenError
messages, which should make debugging simpler.

error.c

@@ -2897,13 +2897,13 @@ rb_error_frozen_object(VALUE frozen_obj)
 	VALUE path = rb_ary_entry(debug_info, 0);
 	VALUE line = rb_ary_entry(debug_info, 1);
 
-        rb_frozen_error_raise(frozen_obj,
-            "can't modify frozen %"PRIsVALUE", created at %"PRIsVALUE":%"PRIsVALUE,
-            CLASS_OF(frozen_obj), path, line);
+	rb_frozen_error_raise(frozen_obj,
+	    "can't modify frozen %"PRIsVALUE": %"PRIsVALUE", created at %"PRIsVALUE":%"PRIsVALUE,
+	    CLASS_OF(frozen_obj), rb_inspect(frozen_obj), path, line);
     }
     else {
-        rb_frozen_error_raise(frozen_obj, "can't modify frozen %"PRIsVALUE,
-            CLASS_OF(frozen_obj));
+	rb_frozen_error_raise(frozen_obj, "can't modify frozen %"PRIsVALUE": %"PRIsVALUE,
+	    CLASS_OF(frozen_obj), rb_inspect(frozen_obj));
     }
 }
 

eval.c

@@ -454,7 +454,7 @@ rb_class_modify_check(VALUE klass)
 		goto noclass;
 	    }
 	}
-        rb_frozen_error_raise(klass, "can't modify frozen %s", desc);
+        rb_frozen_error_raise(klass, "can't modify frozen %s: %"PRIsVALUE, desc, klass);
     }
 }
 

test/ruby/test_rubyoptions.rb

@@ -988,7 +988,7 @@ class TestRubyOptions < Test::Unit::TestCase
 
   def test_frozen_string_literal_debug
     with_debug_pat = /created at/
-    wo_debug_pat = /can\'t modify frozen String \(FrozenError\)\n\z/
+    wo_debug_pat = /can\'t modify frozen String: "\w+" \(FrozenError\)\n\z/
     frozen = [
       ["--enable-frozen-string-literal", true],
       ["--disable-frozen-string-literal", false],

test/ruby/test_variable.rb

@@ -135,7 +135,7 @@ class TestVariable < Test::Unit::TestCase
   def test_special_constant_ivars
     [ true, false, :symbol, "dsym#{rand(9999)}".to_sym, 1, 1.0 ].each do |v|
       assert_empty v.instance_variables
-      msg = "can't modify frozen #{v.class}"
+      msg = "can't modify frozen #{v.class}: #{v.inspect}"
 
       assert_raise_with_message(FrozenError, msg) do
         v.instance_variable_set(:@foo, :bar)