diff --git a/ext/tk/extconf.rb b/ext/tk/extconf.rb
index 02851f727f..fc6d04b58a 100644
--- a/ext/tk/extconf.rb
+++ b/ext/tk/extconf.rb
@@ -1804,12 +1804,6 @@ print("check functions.")
 end
 print("\n") # progress
 
-print("check struct members.")
-have_struct_member("struct RArray", "ptr", "ruby.h")
-print(".") # progress
-have_struct_member("struct RArray", "len", "ruby.h")
-print("\n") # progress
-
 # check libraries
 unless is_win32?
   print("check libraries.")
diff --git a/ext/tk/tcltklib.c b/ext/tk/tcltklib.c
index d164e5cd3b..658ba4bffa 100644
--- a/ext/tk/tcltklib.c
+++ b/ext/tk/tcltklib.c
@@ -3636,11 +3636,7 @@ ip_ruby_cmd(clientData, interp, argc, argv)
         s = rb_tainted_str_new2(str);
 #endif
         DUMP2("arg:%s",str);
-#ifndef HAVE_STRUCT_RARRAY_LEN
         rb_ary_push(args, s);
-#else
-        RARRAY(args)->ptr[RARRAY(args)->len++] = s;
-#endif
     }
 
     if (old_gc == Qfalse) rb_gc_enable();