diff --git a/compiler/rustc_serialize/src/serialize.rs b/compiler/rustc_serialize/src/serialize.rs
index 4213d0a4650e9..32a301a28ae8e 100644
--- a/compiler/rustc_serialize/src/serialize.rs
+++ b/compiler/rustc_serialize/src/serialize.rs
@@ -336,15 +336,11 @@ impl<S: Encoder, T: Encodable<S>, const N: usize> Encodable<S> for [T; N] {
     }
 }
 
-impl<D: Decoder, const N: usize> Decodable<D> for [u8; N] {
-    fn decode(d: &mut D) -> [u8; N] {
+impl<D: Decoder, T: Decodable<D>, const N: usize> Decodable<D> for [T; N] {
+    fn decode(d: &mut D) -> [T; N] {
         let len = d.read_usize();
         assert!(len == N);
-        let mut v = [0u8; N];
-        for i in 0..len {
-            v[i] = Decodable::decode(d);
-        }
-        v
+        std::array::from_fn(move |_| Decodable::decode(d))
     }
 }