Implement rb_obj_as_string correctly.

Author: aardvark179

lib/cext/include/ruby/intern.h

@@ -731,7 +731,7 @@ VALUE rb_str_buf_append(VALUE, VALUE);
 VALUE rb_str_buf_cat(VALUE, const char*, long);
 VALUE rb_str_buf_cat2(VALUE, const char*);
 VALUE rb_str_buf_cat_ascii(VALUE, const char*);
-#define rb_obj_as_string(object) rb_any_to_s(object)
+VALUE rb_obj_as_string(VALUE object);
 VALUE rb_check_string_type(VALUE);
 void rb_must_asciicompat(VALUE);
 #define rb_str_dup(string) rb_obj_dup(string)

lib/truffle/truffle/cext.rb

@@ -1662,6 +1662,10 @@ def rb_any_to_s(object)
     Truffle::Type.rb_any_to_s(object)
   end
 
+  def rb_obj_as_string(object)
+    Truffle::Type.rb_obj_as_string(object)
+  end
+
   def rb_class_inherited_p(ruby_module, object)
     if object.is_a?(Module)
       ruby_module <= object

src/main/c/cext/ruby.c

@@ -438,6 +438,10 @@ VALUE rb_obj_dup(VALUE object) {
   return RUBY_INVOKE(object, "dup");
 }
 
+VALUE rb_obj_as_string(VALUE object) {
+  return RUBY_CEXT_INVOKE("rb_obj_as_string", object);
+}
+
 VALUE rb_any_to_s(VALUE object) {
   return RUBY_CEXT_INVOKE("rb_any_to_s", object);
 }