diff --git a/include/vtype.h b/include/vtype.h
index c9195ab..d807f6d 100644
--- a/include/vtype.h
+++ b/include/vtype.h
@@ -104,7 +104,7 @@ extern vtype_map    map_copy      (const vtype_map*    s)                 Pure__
 extern vtype_set    vset_copy     (const vtype_set*    s)                 Pure__ Warn_unused_result__ Nonnull__(1);
 extern vtype_dict   dict_copy     (const vtype_dict*   s)                 Pure__ Warn_unused_result__ Nonnull__(1);
 extern vtype_list   dict_copy_keys(const vtype_dict*   s)                 Pure__ Warn_unused_result__ Nonnull__(1);
-#define             map_copy_keys(s) vset_copy((vtype_set*)s)
+#define             map_copy_keys(s) vset_copy(_LIBCDSB_nothing(s))
 
 inline vtype_string* string_duplicate   (const vtype_string* s) Always_inline__ Warn_unused_result__ Nonnull__(1);
 extern vtype_array*  array_duplicate    (const vtype_array*  s)                 Warn_unused_result__ Nonnull__(1);
@@ -113,7 +113,7 @@ extern vtype_map*    map_duplicate      (const vtype_map*    s)
 extern vtype_set*    vset_duplicate     (const vtype_set*    s)                 Warn_unused_result__ Nonnull__(1);
 extern vtype_dict*   dict_duplicate     (const vtype_dict*   s)                 Warn_unused_result__ Nonnull__(1);
 extern vtype_list*   dict_duplicate_keys(const vtype_dict*   s)                 Warn_unused_result__ Nonnull__(1);
-#define              map_duplicate_keys(s) vset_duplicate((vtype_set*)s)
+#define              map_duplicate_keys(s) vset_duplicate(_LIBCDSB_nothing(s))
 
 inline void string_copy_init  (vtype_string* x, const vtype_string* s) Always_inline__ Nonnull__(1,2);
 extern void array_copy_init   (vtype_array*  x, const vtype_array*  s)                 Nonnull__(1,2);
@@ -122,7 +122,7 @@ extern void map_copy_init     (vtype_map*    x, const vtype_map*    s)
 extern void vset_copy_init    (vtype_set*    x, const vtype_set*    s)                 Nonnull__(1,2);
 extern void dict_copy_init    (vtype_dict*   x, const vtype_dict*   s)                 Nonnull__(1,2);
 extern void dict_init_keys    (vtype_list*   x, const vtype_dict*   s)                 Nonnull__(1,2);
-#define     map_copy_init_keys(x, s) vset_duplicate(x,  (vtype_set*)s)
+#define     map_copy_init_keys(x, s) vset_copy_init(x, _LIBCDSB_nothing(s))
 
 inline void string_free(vtype_string* x) Always_inline__;
 extern void array_free (vtype_array*  x);