diff --git a/lupa/_lupa.pyx b/lupa/_lupa.pyx
index ad539e68..92f2191e 100644
--- a/lupa/_lupa.pyx
+++ b/lupa/_lupa.pyx
@@ -2544,6 +2544,7 @@ cdef int byte_writer(lua_State* L, void* new_data, size_t new_size, void* desc)
         bd.data = data
         bd.length = bd.length + new_size
     else:
+        bd.length = 0
         free(data)
         return 1
     return 0
\ No newline at end of file
diff --git a/lupa/luaapi.pxd b/lupa/luaapi.pxd
index 9fd70792..58f956f7 100644
--- a/lupa/luaapi.pxd
+++ b/lupa/luaapi.pxd
@@ -273,22 +273,18 @@ cdef extern from "lua.h" nogil:
 cdef extern from "lstate.h" nogil:
     cppclass Proto:
         pass
-    ctypedef Proto Proto
 
     ctypedef struct LClosure:
         Proto* p
 
     union Closure:
         LClosure l
-    ctypedef Closure Closure
 
     union GCObject:
         Closure cl
-    ctypedef GCObject GCObject
 
     union Value:
         GCObject* gc
-    ctypedef Value Value
 
     ctypedef struct lua_TValue:
         Value value