diff --git a/crates/env/src/types.rs b/crates/env/src/types.rs
index fff2d3a8868..a813d6016ca 100644
--- a/crates/env/src/types.rs
+++ b/crates/env/src/types.rs
@@ -211,22 +211,19 @@ pub type RentFraction = Perbill;
 /// This is a mirror of the `AccountId` type used in the default configuration
 /// of PALLET contracts.
 #[derive(
-    Debug,
-    Copy,
-    Clone,
-    PartialEq,
-    Eq,
-    Ord,
-    PartialOrd,
-    Hash,
-    Encode,
-    Decode,
-    From,
-    Default,
+    Debug, Copy, Clone, PartialEq, Eq, Ord, PartialOrd, Hash, Encode, From, Default,
 )]
 #[cfg_attr(feature = "std", derive(TypeInfo))]
 pub struct AccountId([u8; 32]);
 
+impl Decode for AccountId {
+    fn decode<I: scale::Input>(input: &mut I) -> Result<Self, scale::Error> {
+        let mut account_id = AccountId { 0: [0; 32] };
+        input.read(account_id.0.as_mut_slice())?;
+        Ok(account_id)
+    }
+}
+
 impl AsRef<[u8; 32]> for AccountId {
     #[inline]
     fn as_ref(&self) -> &[u8; 32] {
@@ -271,22 +268,19 @@ impl<'a> TryFrom<&'a [u8]> for AccountId {
 /// This is a mirror of the `Hash` type used in the default configuration
 /// of PALLET contracts.
 #[derive(
-    Debug,
-    Copy,
-    Clone,
-    PartialEq,
-    Eq,
-    Ord,
-    PartialOrd,
-    Hash,
-    Encode,
-    Decode,
-    From,
-    Default,
+    Debug, Copy, Clone, PartialEq, Eq, Ord, PartialOrd, Hash, Encode, From, Default,
 )]
 #[cfg_attr(feature = "std", derive(TypeInfo))]
 pub struct Hash([u8; 32]);
 
+impl Decode for Hash {
+    fn decode<I: scale::Input>(input: &mut I) -> Result<Self, scale::Error> {
+        let mut hash = Hash { 0: [0; 32] };
+        input.read(hash.0.as_mut_slice())?;
+        Ok(hash)
+    }
+}
+
 impl<'a> TryFrom<&'a [u8]> for Hash {
     type Error = TryFromSliceError;
 
diff --git a/crates/primitives/src/key.rs b/crates/primitives/src/key.rs
index fafb20e4e3a..86ff7d66690 100644
--- a/crates/primitives/src/key.rs
+++ b/crates/primitives/src/key.rs
@@ -179,8 +179,9 @@ impl scale::Decode for Key {
     where
         I: scale::Input,
     {
-        let bytes = <[u8; 32] as scale::Decode>::decode(input)?;
-        Ok(Self::from(bytes))
+        let mut key = Key { 0: [0; 32] };
+        input.read(key.0.as_mut_slice())?;
+        Ok(key)
     }
 
     #[inline]