diff --git a/include/cpptrace/forward.hpp b/include/cpptrace/forward.hpp
index 84fb2e8..840d53a 100644
--- a/include/cpptrace/forward.hpp
+++ b/include/cpptrace/forward.hpp
@@ -13,6 +13,7 @@ namespace cpptrace {
 
     struct object_frame;
     struct stacktrace_frame;
+    struct safe_object_frame;
 }
 
 #endif
diff --git a/src/binary/object.hpp b/src/binary/object.hpp
index 24415d3..933d6cd 100644
--- a/src/binary/object.hpp
+++ b/src/binary/object.hpp
@@ -1,16 +1,13 @@
 #ifndef OBJECT_HPP
 #define OBJECT_HPP
 
+#include <cpptrace/forward.hpp>
+
 #include <vector>
 #include <cstdint>
 
 namespace cpptrace {
 
-struct object_frame;
-struct safe_object_frame;
-
-using frame_ptr = std::uintptr_t;
-
 namespace detail {
     object_frame get_frame_object_info(frame_ptr address);