diff --git a/src/duk_features.h.in b/src/duk_features.h.in
index b49c9ce8..8e658a00 100644
--- a/src/duk_features.h.in
+++ b/src/duk_features.h.in
@@ -893,14 +893,14 @@ typedef duk_small_int_t duk_bool_t;
 /* Index values must have at least 32-bit signed range. */
 typedef duk_int_t duk_idx_t;
 
-/* Array index values, currently same type, could be exact 32 bits. */
-typedef duk_int_t duk_arridx_t;
+/* Array index values, could be exact 32 bits. */
+typedef duk_uint_t duk_arridx_t;
 
 /* Duktape/C function return value, platform int is enough for now to
  * represent 0, 1, or negative error code.  Must be compatible with
  * assigning truth values (e.g. duk_ret_t rc = (foo == bar);).
  */
-typedef int duk_ret_t;
+typedef duk_small_int_t duk_ret_t;
 
 /* Error codes are represented with platform int. */
 typedef duk_small_int_t duk_errcode_t;
@@ -912,8 +912,8 @@ typedef duk_small_int_t duk_errcode_t;
  * ensure duk_uint32_t casts back and forth nicely.  Almost everything
  * else uses the signed one.
  */
-typedef duk_int32_t duk_codepoint_t;
-typedef duk_uint32_t duk_ucodepoint_t;
+typedef duk_int_fast32_t duk_codepoint_t;
+typedef duk_uint_fast32_t duk_ucodepoint_t;
 
 /* IEEE double typedef. */
 typedef double duk_double_t;