Data: delete

Has been deprecated since 684bdf6171.

Matz says in [ruby-core:83954] that Data should be an alias of Object.
Because rb_cData has not been deprecated, let us deprecate the constant
to make it a C-level synonym of rb_cObject.

error.c

@@ -2786,7 +2786,7 @@ Init_Exception(void)
     rb_define_method(rb_eNameError, "name", name_err_name, 0);
     rb_define_method(rb_eNameError, "receiver", name_err_receiver, 0);
     rb_define_method(rb_eNameError, "local_variables", name_err_local_variables, 0);
-    rb_cNameErrorMesg = rb_define_class_under(rb_eNameError, "message", rb_cData);
+    rb_cNameErrorMesg = rb_define_class_under(rb_eNameError, "message", rb_cObject);
     rb_define_method(rb_cNameErrorMesg, "==", name_err_mesg_equal, 1);
     rb_define_method(rb_cNameErrorMesg, "to_str", name_err_mesg_to_str, 0);
     rb_define_method(rb_cNameErrorMesg, "_dump", name_err_mesg_dump, 1);

include/ruby/internal/globals.h

@@ -20,6 +20,7 @@
  *             extension libraries. They could be written in C++98.
  * @brief      Ruby-level global variables / constants, visible from C.
  */
+#include "ruby/internal/attr/deprecated.h"
 #include "ruby/internal/attr/pure.h"
 #include "ruby/internal/dllexport.h"
 #include "ruby/internal/fl_type.h"
@@ -48,6 +49,7 @@ RUBY_EXTERN VALUE rb_cArray;
 RUBY_EXTERN VALUE rb_cBinding;
 RUBY_EXTERN VALUE rb_cClass;
 RUBY_EXTERN VALUE rb_cCont;
+RBIMPL_ATTR_DEPRECATED(("by: rb_cObject.  Will be removed in 3.1."))
 RUBY_EXTERN VALUE rb_cData;
 RUBY_EXTERN VALUE rb_cDir;
 RUBY_EXTERN VALUE rb_cEncoding;

object.c

@@ -32,6 +32,7 @@
 #include "internal/struct.h"
 #include "internal/symbol.h"
 #include "internal/variable.h"
+#include "internal/warnings.h"
 #include "probes.h"
 #include "ruby/encoding.h"
 #include "ruby/st.h"
@@ -4330,6 +4331,25 @@ f_sprintf(int c, const VALUE *v, VALUE _)
     return rb_f_sprintf(c, v);
 }
 
+COMPILER_WARNING_PUSH
+#if defined(_MSC_VER)
+COMPILER_WARNING_IGNORED(4996)
+#elif defined(__INTEL_COMPILER)
+COMPILER_WARNING_IGNORED(1786)
+#elif __has_warning("-Wdeprecated-declarations")
+COMPILER_WARNING_IGNORED(-Wdeprecated-declarations)
+#elif defined(__GNUC__)
+COMPILER_WARNING_IGNORED(-Wdeprecated-declarations)
+#endif
+
+static inline void
+Init_rb_cData(void)
+{
+    rb_cData = rb_cObject;
+}
+
+COMPILER_WARNING_POP
+
 /*
  *  Document-class: Class
  *
@@ -4662,15 +4682,7 @@ InitVM_Object(void)
     rb_undef_method(rb_cClass, "append_features");
     rb_undef_method(rb_cClass, "prepend_features");
 
-    /*
+    Init_rb_cData();
-     * Document-class: Data
-     *
-     * This is a deprecated class, base class for C extensions using
-     * Data_Make_Struct or Data_Wrap_Struct.
-     */
-    rb_cData = rb_define_class("Data", rb_cObject);
-    rb_undef_alloc_func(rb_cData);
-    rb_deprecate_constant(rb_cObject, "Data");
 
     rb_cTrueClass = rb_define_class("TrueClass", rb_cObject);
     rb_cTrueClass_to_s = rb_fstring_enc_lit("true", rb_usascii_encoding());

spec/ruby/core/data/constants_spec.rb

@@ -1,5 +1,6 @@
 require_relative '../../spec_helper'
 
+ruby_version_is ''...'2.8' do
   describe "Data" do
     it "is a subclass of Object" do
       suppress_warning do
@@ -11,3 +12,4 @@ describe "Data" do
       -> { Data }.should complain(/constant ::Data is deprecated/)
     end
   end
+end

transcode.c

@@ -4462,7 +4462,7 @@ InitVM_transcode(void)
     rb_define_method(rb_cString, "encode", str_encode, -1);
     rb_define_method(rb_cString, "encode!", str_encode_bang, -1);
 
-    rb_cEncodingConverter = rb_define_class_under(rb_cEncoding, "Converter", rb_cData);
+    rb_cEncodingConverter = rb_define_class_under(rb_cEncoding, "Converter", rb_cObject);
     rb_define_alloc_func(rb_cEncodingConverter, econv_s_allocate);
     rb_define_singleton_method(rb_cEncodingConverter, "asciicompat_encoding", econv_s_asciicompat_encoding, 1);
     rb_define_singleton_method(rb_cEncodingConverter, "search_convpath", econv_s_search_convpath, -1);