Add correct behaviour for rb_class2name.

Author: aardvark179

CHANGELOG.md

@@ -29,6 +29,9 @@ Compatibility:
 * Fix `Kernel#sprintf` formatting for `%c` when used non-ASCII encoding (#2369, @andrykonchin).
 * Fix `Kernel#sprintf` argument casting for `%c` (@andrykonchin).
 * Implement the `rb_enc_strlen` function for use by native extensions (@nirvdrum).
+* Match tag values used by `rb_protect` and `rb_jump_tag` for the `tk` gem (#2556, @aardvark179).
+* Implement `rb_eval_cmd_kw` to support the `tk` gem (#2556, @aardvark179).
+* Fix `rb_class2name` to call `inspect` on anonymous classes like in CRuby (#2701, @aardvark179).
 
 Performance:
 

src/main/c/cext/class.c

@@ -71,7 +71,7 @@ VALUE rb_class_name(VALUE ruby_class) {
   VALUE name = RUBY_INVOKE(ruby_class, "name");
 
   if (NIL_P(name)) {
-    return rb_class_name(rb_obj_class(ruby_class));
+    return RUBY_INVOKE(ruby_class, "inspect");
   } else {
     return name;
   }