diff --git a/substrate/node/runtime/src/lib.rs b/substrate/node/runtime/src/lib.rs
index 71af5d9417..2b8750d2de 100644
--- a/substrate/node/runtime/src/lib.rs
+++ b/substrate/node/runtime/src/lib.rs
@@ -75,8 +75,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// and set impl_version to equal spec_version. If only runtime
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
-	spec_version: 117,
-	impl_version: 117,
+	spec_version: 118,
+	impl_version: 118,
 	apis: RUNTIME_API_VERSIONS,
 };
 
diff --git a/substrate/srml/generic-asset/src/lib.rs b/substrate/srml/generic-asset/src/lib.rs
index 884f4e9b9b..60947e68eb 100644
--- a/substrate/srml/generic-asset/src/lib.rs
+++ b/substrate/srml/generic-asset/src/lib.rs
@@ -336,7 +336,7 @@ decl_module! {
 
 			<NextAssetId<T>>::put(next_id);
 			<TotalIssuance<T>>::insert(id, &options.initial_issuance);
-			<FreeBalance<T>>::insert(&id, &origin, options.initial_issuance);
+			<FreeBalance<T>>::insert(&id, &origin, &options.initial_issuance);
 			<Permissions<T>>::insert(&id, permissions);
 
 			Self::deposit_event(RawEvent::Created(id, origin, options));
@@ -560,7 +560,7 @@ impl<T: Trait> Module<T> {
 		let permissions: PermissionVersions<T::AccountId> = options.permissions.clone().into();
 
 		<TotalIssuance<T>>::insert(asset_id, &options.initial_issuance);
-		<FreeBalance<T>>::insert(&asset_id, &account_id, options.initial_issuance);
+		<FreeBalance<T>>::insert(&asset_id, &account_id, &options.initial_issuance);
 		<Permissions<T>>::insert(&asset_id, permissions);
 
 		Self::deposit_event(RawEvent::Created(asset_id, account_id, options));
@@ -768,13 +768,13 @@ impl<T: Trait> Module<T> {
 	/// NOTE: LOW-LEVEL: This will not attempt to maintain total issuance. It is expected that
 	/// the caller will do this.
 	fn set_reserved_balance(asset_id: &T::AssetId, who: &T::AccountId, balance: T::Balance) {
-		<ReservedBalance<T>>::insert(asset_id, who, balance);
+		<ReservedBalance<T>>::insert(asset_id, who, &balance);
 	}
 
 	/// NOTE: LOW-LEVEL: This will not attempt to maintain total issuance. It is expected that
 	/// the caller will do this.
 	fn set_free_balance(asset_id: &T::AssetId, who: &T::AccountId, balance: T::Balance) {
-		<FreeBalance<T>>::insert(asset_id, who, balance);
+		<FreeBalance<T>>::insert(asset_id, who, &balance);
 	}
 
 	fn set_lock(
diff --git a/substrate/srml/im-online/src/lib.rs b/substrate/srml/im-online/src/lib.rs
index f1868c599b..e2b23f1dbd 100644
--- a/substrate/srml/im-online/src/lib.rs
+++ b/substrate/srml/im-online/src/lib.rs
@@ -200,13 +200,13 @@ decl_module! {
 			ensure_none(origin)?;
 
 			let current_session = <session::Module<T>>::current_index();
-			let exists = <ReceivedHeartbeats<T>>::exists(current_session, &heartbeat.authority_id);
+			let exists = <ReceivedHeartbeats<T>>::exists(&current_session, &heartbeat.authority_id);
 			if !exists {
 				let now = <system::Module<T>>::block_number();
 				Self::deposit_event(RawEvent::HeartbeatReceived(now, heartbeat.authority_id.clone()));
 
 				let network_state = heartbeat.network_state.encode();
-				<ReceivedHeartbeats<T>>::insert(current_session, &heartbeat.authority_id, network_state);
+				<ReceivedHeartbeats<T>>::insert(&current_session, &heartbeat.authority_id, &network_state);
 			}
 		}
 
@@ -301,13 +301,13 @@ impl<T: Trait> Module<T> {
 			Some(start) => {
 				// iterate over every session
 				for index in start..curr  {
-					if <ReceivedHeartbeats<T>>::exists(index, authority_id) {
+					if <ReceivedHeartbeats<T>>::exists(&index, authority_id) {
 						return true;
 					}
 				}
 				false
 			},
-			None => <ReceivedHeartbeats<T>>::exists(curr, authority_id),
+			None => <ReceivedHeartbeats<T>>::exists(&curr, authority_id),
 		}
 	}
 
@@ -315,7 +315,7 @@ impl<T: Trait> Module<T> {
 	/// during the current session. Otherwise `false`.
 	pub fn is_online_in_current_session(authority_id: &T::AuthorityId) -> bool {
 		let current_session = <session::Module<T>>::current_index();
-		<ReceivedHeartbeats<T>>::exists(current_session, authority_id)
+		<ReceivedHeartbeats<T>>::exists(&current_session, authority_id)
 	}
 
 	/// Session has just changed.
@@ -345,10 +345,10 @@ impl<T: Trait> Module<T> {
 		match LastNewEraStart::get() {
 			Some(start) => {
 				for index in start..curr {
-					<ReceivedHeartbeats<T>>::remove_prefix(index);
+					<ReceivedHeartbeats<T>>::remove_prefix(&index);
 				}
 			},
-			None => <ReceivedHeartbeats<T>>::remove_prefix(curr),
+			None => <ReceivedHeartbeats<T>>::remove_prefix(&curr),
 		}
 	}
 }
diff --git a/substrate/srml/session/src/lib.rs b/substrate/srml/session/src/lib.rs
index 5495cdbe65..d425c44e2e 100644
--- a/substrate/srml/session/src/lib.rs
+++ b/substrate/srml/session/src/lib.rs
@@ -120,14 +120,12 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use rstd::{prelude::*, marker::PhantomData, ops::{Sub, Rem}};
-use parity_codec::{Decode, Encode};
+use parity_codec::Decode;
 use primitives::KeyTypeId;
-use primitives::traits::{Convert, Zero, Member, OpaqueKeys, TypedKey, Hash};
+use primitives::traits::{Convert, Zero, Member, OpaqueKeys, TypedKey};
 use srml_support::{
-	dispatch::Result,
-	storage,
-	ConsensusEngineId, StorageValue, for_each_tuple, decl_module,
-	decl_event, decl_storage,
+	dispatch::Result, ConsensusEngineId, StorageValue, StorageDoubleMap, for_each_tuple,
+	decl_module, decl_event, decl_storage,
 };
 use srml_support::{ensure, traits::{OnFreeBalanceZero, Get, FindAuthor}, Parameter};
 use system::{self, ensure_signed};
@@ -283,8 +281,7 @@ pub trait Trait: system::Trait {
 	type SelectInitialValidators: SelectInitialValidators<Self::ValidatorId>;
 }
 
-const DEDUP_KEY_LEN: usize = 13;
-const DEDUP_KEY_PREFIX: &[u8; DEDUP_KEY_LEN] = b":session:keys";
+const DEDUP_KEY_PREFIX: &[u8] = b":session:keys";
 
 decl_storage! {
 	trait Store for Module<T: Trait> as Session {
@@ -304,6 +301,17 @@ decl_storage! {
 		/// will be used to determine the validator's session keys.
 		QueuedKeys get(queued_keys): Vec<(T::ValidatorId, T::Keys)>;
 
+		/// The next session keys for a validator.
+		///
+		/// The first key is always `DEDUP_KEY_PREFIX` to have all the data in the same branch of
+		/// the trie. Having all data in the same branch should prevent slowing down other queries.
+		NextKeys: double_map hasher(twox_64_concat) Vec<u8>, blake2_256(T::ValidatorId) => Option<T::Keys>;
+
+		/// The owner of a key. The second key is the `KeyTypeId` + the encoded key.
+		///
+		/// The first key is always `DEDUP_KEY_PREFIX` to have all the data in the same branch of
+		/// the trie. Having all data in the same branch should prevent slowing down other queries.
+		KeyOwner: double_map hasher(twox_64_concat) Vec<u8>, blake2_256((KeyTypeId, Vec<u8>)) => Option<T::ValidatorId>;
 	}
 	add_extra_genesis {
 		config(keys): Vec<(T::ValidatorId, T::Keys)>;
@@ -354,6 +362,10 @@ decl_event!(
 
 decl_module! {
 	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
+		/// Used as first key for `NextKeys` and `KeyOwner` to put all the data into the same branch
+		/// of the trie.
+		const DEDUP_KEY_PREFIX: &[u8] = DEDUP_KEY_PREFIX;
+
 		fn deposit_event() = default;
 
 		/// Sets the session key(s) of the function caller to `key`.
@@ -494,47 +506,31 @@ impl<T: Trait> Module<T> {
 		}
 	}
 
-	// Child trie storage.
-
 	fn load_keys(v: &T::ValidatorId) -> Option<T::Keys> {
-		storage::unhashed::get(&dedup_trie_key::<T, _>(v))
+		<NextKeys<T>>::get(DEDUP_KEY_PREFIX, v)
 	}
 
 	fn take_keys(v: &T::ValidatorId) -> Option<T::Keys> {
-		storage::unhashed::take(&dedup_trie_key::<T, _>(v))
+		<NextKeys<T>>::take(DEDUP_KEY_PREFIX, v)
 	}
 
 	fn put_keys(v: &T::ValidatorId, keys: &T::Keys) {
-		storage::unhashed::put(&dedup_trie_key::<T, _>(v), keys)
+		<NextKeys<T>>::insert(DEDUP_KEY_PREFIX, v, keys);
 	}
 
 	fn key_owner(id: KeyTypeId, key_data: &[u8]) -> Option<T::ValidatorId> {
-		storage::unhashed::get(&dedup_trie_key::<T, _>(&(id, key_data)))
+		<KeyOwner<T>>::get(DEDUP_KEY_PREFIX, &(id, key_data.to_vec()))
 	}
 
 	fn put_key_owner(id: KeyTypeId, key_data: &[u8], v: &T::ValidatorId) {
-		storage::unhashed::put(&dedup_trie_key::<T, _>(&(id, key_data)), v);
+		<KeyOwner<T>>::insert(DEDUP_KEY_PREFIX, &(id, key_data.to_vec()), v)
 	}
 
 	fn clear_key_owner(id: KeyTypeId, key_data: &[u8]) {
-		storage::unhashed::kill(&dedup_trie_key::<T, _>(&(id, key_data)));
+		<KeyOwner<T>>::remove(DEDUP_KEY_PREFIX, &(id, key_data.to_vec()));
 	}
 }
 
-fn dedup_trie_key<T: Trait, K: Encode>(key: &K) -> [u8; 32 + DEDUP_KEY_LEN] {
-	key.using_encoded(|s| {
-		// take at most 32 bytes from the hash of the value.
-		let hash = <T as system::Trait>::Hashing::hash(s);
-		let hash: &[u8] = hash.as_ref();
-		let len = rstd::cmp::min(hash.len(), 32);
-
-		let mut data = [0; 32 + DEDUP_KEY_LEN];
-		data[..DEDUP_KEY_LEN].copy_from_slice(DEDUP_KEY_PREFIX);
-		data[DEDUP_KEY_LEN..][..len].copy_from_slice(hash);
-		data
-	})
-}
-
 impl<T: Trait> OnFreeBalanceZero<T::ValidatorId> for Module<T> {
 	fn on_free_balance_zero(who: &T::ValidatorId) {
 		Self::prune_dead_keys(who);
diff --git a/substrate/srml/support/procedural/src/lib.rs b/substrate/srml/support/procedural/src/lib.rs
index f6da2f751d..78051ee8f2 100644
--- a/substrate/srml/support/procedural/src/lib.rs
+++ b/substrate/srml/support/procedural/src/lib.rs
@@ -18,7 +18,7 @@
 //! Proc macro of Support code for the runtime.
 // end::description[]
 
-#![recursion_limit="256"]
+#![recursion_limit="512"]
 
 extern crate proc_macro;
 
diff --git a/substrate/srml/support/procedural/src/storage/impls.rs b/substrate/srml/support/procedural/src/storage/impls.rs
index d5dc91635b..45d7fada9f 100644
--- a/substrate/srml/support/procedural/src/storage/impls.rs
+++ b/substrate/srml/support/procedural/src/storage/impls.rs
@@ -694,13 +694,18 @@ impl<'a, I: Iterator<Item=syn::Meta>> Impls<'a, I> {
 
 		let mutate_impl = if !is_option {
 			quote!{
-				#as_double_map::insert(key1, key2, &val, storage)
+				#as_double_map::insert(k1, k2, &val, storage)
 			}
 		} else {
 			quote!{
 				match val {
-					Some(ref val) => #as_double_map::insert(key1, key2, &val, storage),
-					None => #as_double_map::remove(key1, key2, storage),
+					Some(ref val) => #as_double_map::insert::<KArg1, KArg2, #typ, S>(
+						k1,
+						k2,
+						val,
+						storage,
+					),
+					None => #as_double_map::remove(k1, k2, storage),
 				}
 			}
 		};
@@ -751,7 +756,10 @@ impl<'a, I: Iterator<Item=syn::Meta>> Impls<'a, I> {
 			{
 				type Query = #value_type;
 
-				fn prefix_for(k1: &#k1ty) -> Vec<u8> {
+				fn prefix_for<KArg1>(k1: &KArg1) -> #scrate::rstd::vec::Vec<u8> where
+					KArg1: ?Sized + #scrate::codec::Encode,
+					#k1ty: #scrate::rstd::borrow::Borrow<KArg1>,
+				{
 					use #scrate::storage::hashed::generator::StorageHasher;
 
 					let mut key = #as_double_map::prefix().to_vec();
@@ -763,7 +771,15 @@ impl<'a, I: Iterator<Item=syn::Meta>> Impls<'a, I> {
 					#final_prefix
 				}
 
-				fn key_for(k1: &#k1ty, k2: &#k2ty) -> Vec<u8> {
+				fn key_for<KArg1, KArg2>(
+					k1: &KArg1,
+					k2: &KArg2,
+				) -> #scrate::rstd::vec::Vec<u8> where
+					#k1ty: #scrate::rstd::borrow::Borrow<KArg1>,
+					#k2ty: #scrate::rstd::borrow::Borrow<KArg2>,
+					KArg1: ?Sized + #scrate::codec::Encode,
+					KArg2: ?Sized + #scrate::codec::Encode,
+				{
 					use #scrate::storage::hashed::generator::StorageHasher;
 
 					let mut key = #as_double_map::prefix_for(k1);
@@ -771,25 +787,50 @@ impl<'a, I: Iterator<Item=syn::Meta>> Impls<'a, I> {
 					key
 				}
 
-				fn get<S: #scrate::UnhashedStorage>(key1: &#k1ty, key2: &#k2ty, storage: &S) -> Self::Query {
-					let key = #as_double_map::key_for(key1, key2);
+				fn get<KArg1, KArg2, S: #scrate::UnhashedStorage>(
+					k1: &KArg1,
+					k2: &KArg2,
+					storage: &S,
+				) -> Self::Query where
+					#k1ty: #scrate::rstd::borrow::Borrow<KArg1>,
+					#k2ty: #scrate::rstd::borrow::Borrow<KArg2>,
+					KArg1: ?Sized + #scrate::codec::Encode,
+					KArg2: ?Sized + #scrate::codec::Encode,
+				{
+					let key = #as_double_map::key_for(k1, k2);
 					storage.get(&key).#option_simple_1(|| #fielddefault)
 				}
 
-				fn take<S: #scrate::UnhashedStorage>(key1: &#k1ty, key2: &#k2ty, storage: &mut S) -> Self::Query {
-					let key = #as_double_map::key_for(key1, key2);
+				fn take<KArg1, KArg2, S: #scrate::UnhashedStorage>(
+					k1: &KArg1,
+					k2: &KArg2,
+					storage: &mut S,
+				) -> Self::Query where
+					#k1ty: #scrate::rstd::borrow::Borrow<KArg1>,
+					#k2ty: #scrate::rstd::borrow::Borrow<KArg2>,
+					KArg1: ?Sized + #scrate::codec::Encode,
+					KArg2: ?Sized + #scrate::codec::Encode,
+				{
+					let key = #as_double_map::key_for(k1, k2);
 					storage.take(&key).#option_simple_1(|| #fielddefault)
 				}
 
-				fn mutate<R, F, S>(key1: &#k1ty, key2: &#k2ty, f: F, storage: &mut S) -> R
-				where
+				fn mutate<KArg1, KArg2, R, F, S: #scrate::UnhashedStorage>(
+					k1: &KArg1,
+					k2: &KArg2,
+					f: F,
+					storage: &mut S,
+				) -> R where
+					#k1ty: #scrate::rstd::borrow::Borrow<KArg1>,
+					#k2ty: #scrate::rstd::borrow::Borrow<KArg2>,
+					KArg1: ?Sized + #scrate::codec::Encode,
+					KArg2: ?Sized + #scrate::codec::Encode,
 					F: FnOnce(&mut Self::Query) -> R,
-					S: #scrate::UnhashedStorage,
 				{
-					let mut val = #as_double_map::get(key1, key2, storage);
+					let mut val = #as_double_map::get(k1, k2, storage);
 
 					let ret = f(&mut val);
-					#mutate_impl ;
+					#mutate_impl;
 					ret
 				}
 			}
diff --git a/substrate/srml/support/procedural/src/storage/transformation.rs b/substrate/srml/support/procedural/src/storage/transformation.rs
index 6f0cf93179..ae0531c57d 100644
--- a/substrate/srml/support/procedural/src/storage/transformation.rs
+++ b/substrate/srml/support/procedural/src/storage/transformation.rs
@@ -905,15 +905,17 @@ fn impl_store_fns(
 					};
 
 					quote!{
-						pub fn #get_fn<KArg1, KArg2>(k1: KArg1, k2: KArg2) -> #value_type
+						pub fn #get_fn<KArg1, KArg2>(k1: &KArg1, k2: &KArg2) -> #value_type
 						where
-							KArg1: #scrate::rstd::borrow::Borrow<#key1_type>,
-							KArg2: #scrate::rstd::borrow::Borrow<#key2_type>,
+							#key1_type: #scrate::rstd::borrow::Borrow<KArg1>,
+							#key2_type: #scrate::rstd::borrow::Borrow<KArg2>,
+							KArg1: ?Sized + #scrate::codec::Encode,
+							KArg2: ?Sized + #scrate::codec::Encode,
 						{
 							<
 								#name<#struct_trait #instance> as
 								#scrate::storage::unhashed::generator::StorageDoubleMap<#key1_type, #key2_type, #typ>
-							>::get(k1.borrow(), k2.borrow(), &#scrate::storage::RuntimeStorage)
+							>::get(k1, k2, &#scrate::storage::RuntimeStorage)
 						}
 					}
 				}
diff --git a/substrate/srml/support/src/double_map.rs b/substrate/srml/support/src/double_map.rs
index d35570ae4f..aec7f497a6 100644
--- a/substrate/srml/support/src/double_map.rs
+++ b/substrate/srml/support/src/double_map.rs
@@ -34,8 +34,8 @@ use sr_std::borrow::Borrow;
 ///
 /// Hasher are implemented in derive_key* methods.
 pub trait StorageDoubleMapWithHasher {
-	type Key1: Codec;
-	type Key2: Codec;
+	type Key1: Encode;
+	type Key2: Encode;
 	type Value: Codec + Default;
 
 	const PREFIX: &'static [u8];
diff --git a/substrate/srml/support/src/lib.rs b/substrate/srml/support/src/lib.rs
index 361fef969b..e1300c5925 100644
--- a/substrate/srml/support/src/lib.rs
+++ b/substrate/srml/support/src/lib.rs
@@ -387,32 +387,32 @@ mod tests {
 			// get / insert / take
 			let key1 = 17u32;
 			let key2 = 18u32;
-			assert_eq!(DoubleMap::get(key1, key2), 0u64);
-			DoubleMap::insert(key1, key2, 4u64);
-			assert_eq!(DoubleMap::get(key1, key2), 4u64);
-			assert_eq!(DoubleMap::take(key1, key2), 4u64);
-			assert_eq!(DoubleMap::get(key1, key2), 0u64);
+			assert_eq!(DoubleMap::get(&key1, &key2), 0u64);
+			DoubleMap::insert(&key1, &key2, &4u64);
+			assert_eq!(DoubleMap::get(&key1, &key2), 4u64);
+			assert_eq!(DoubleMap::take(&key1, &key2), 4u64);
+			assert_eq!(DoubleMap::get(&key1, &key2), 0u64);
 
 			// mutate
-			DoubleMap::mutate(key1, key2, |val| {
+			DoubleMap::mutate(&key1, &key2, |val| {
 				*val = 15;
 			});
-			assert_eq!(DoubleMap::get(key1, key2), 15u64);
+			assert_eq!(DoubleMap::get(&key1, &key2), 15u64);
 
 			// remove
-			DoubleMap::remove(key1, key2);
-			assert_eq!(DoubleMap::get(key1, key2), 0u64);
+			DoubleMap::remove(&key1, &key2);
+			assert_eq!(DoubleMap::get(&key1, &key2), 0u64);
 
 			// remove prefix
-			DoubleMap::insert(key1, key2, 4u64);
-			DoubleMap::insert(key1, key2+1, 4u64);
-			DoubleMap::insert(key1+1, key2, 4u64);
-			DoubleMap::insert(key1+1, key2+1, 4u64);
-			DoubleMap::remove_prefix(key1);
-			assert_eq!(DoubleMap::get(key1, key2), 0u64);
-			assert_eq!(DoubleMap::get(key1, key2+1), 0u64);
-			assert_eq!(DoubleMap::get(key1+1, key2), 4u64);
-			assert_eq!(DoubleMap::get(key1+1, key2+1), 4u64);
+			DoubleMap::insert(&key1, &key2, &4u64);
+			DoubleMap::insert(&key1, &(key2 + 1), &4u64);
+			DoubleMap::insert(&(key1 + 1), &key2, &4u64);
+			DoubleMap::insert(&(key1 + 1), &(key2 + 1), &4u64);
+			DoubleMap::remove_prefix(&key1);
+			assert_eq!(DoubleMap::get(&key1, &key2), 0u64);
+			assert_eq!(DoubleMap::get(&key1, &(key2 + 1)), 0u64);
+			assert_eq!(DoubleMap::get(&(key1 + 1), &key2), 4u64);
+			assert_eq!(DoubleMap::get(&(key1 + 1), &(key2 + 1)), 4u64);
 
 		});
 	}
@@ -425,9 +425,9 @@ mod tests {
 			let key1 = 17u32;
 			let key2 = 18u32;
 
-			DoubleMap::insert(key1, key2, vec![1]);
-			DoubleMap::append(key1, key2, &[2, 3]).unwrap();
-			assert_eq!(DoubleMap::get(key1, key2), vec![1, 2, 3]);
+			DoubleMap::insert(&key1, &key2, &vec![1]);
+			DoubleMap::append(&key1, &key2, &[2, 3]).unwrap();
+			assert_eq!(DoubleMap::get(&key1, &key2), &[1, 2, 3]);
 		});
 	}
 
diff --git a/substrate/srml/support/src/storage/mod.rs b/substrate/srml/support/src/storage/mod.rs
index db9e4bc31d..446855b55c 100644
--- a/substrate/srml/support/src/storage/mod.rs
+++ b/substrate/srml/support/src/storage/mod.rs
@@ -104,7 +104,7 @@ impl UnhashedStorage for RuntimeStorage {
 	}
 
 	/// Put a value in under a key.
-	fn put<T: Encode>(&mut self, key: &[u8], val: &T) {
+	fn put<T: Encode + ?Sized>(&mut self, key: &[u8], val: &T) {
 		unhashed::put(key, val)
 	}
 
@@ -332,60 +332,83 @@ impl<K: Codec, V: Codec, U> EnumerableStorageMap<K, V> for U
 /// is a hash of a `Key2`.
 ///
 /// /!\ be careful while choosing the Hash, indeed malicious could craft second keys to lower the trie.
-pub trait StorageDoubleMap<K1: Codec, K2: Codec, V: Codec> {
+pub trait StorageDoubleMap<K1: Encode, K2: Encode, V: Codec> {
 	/// The type that get/take returns.
 	type Query;
 
-	/// Get the prefix key in storage.
 	fn prefix() -> &'static [u8];
 
-	/// Get the storage key used to fetch a value corresponding to a specific key.
-	fn key_for<KArg1: Borrow<K1>, KArg2: Borrow<K2>>(k1: KArg1, k2: KArg2) -> Vec<u8>;
-
-	/// Get the storage prefix used to fetch keys corresponding to a specific key1.
-	fn prefix_for<KArg1: Borrow<K1>>(k1: KArg1) -> Vec<u8>;
-
-	/// true if the value is defined in storage.
-	fn exists<KArg1: Borrow<K1>, KArg2: Borrow<K2>>(k1: KArg1, k2: KArg2) -> bool;
-
-	/// Load the value associated with the given key from the map.
-	fn get<KArg1: Borrow<K1>, KArg2: Borrow<K2>>(k1: KArg1, k2: KArg2) -> Self::Query;
-
-	/// Take the value under a key.
-	fn take<KArg1: Borrow<K1>, KArg2: Borrow<K2>>(k1: KArg1, k2: KArg2) -> Self::Query;
-
-	/// Store a value to be associated with the given key from the map.
-	fn insert<KArg1: Borrow<K1>, KArg2: Borrow<K2>, VArg: Borrow<V>>(k1: KArg1, k2: KArg2, val: VArg);
-
-	/// Remove the value under a key.
-	fn remove<KArg1: Borrow<K1>, KArg2: Borrow<K2>>(k1: KArg1, k2: KArg2);
-
-	/// Removes all entries that shares the `k1` as the first key.
-	fn remove_prefix<KArg1: Borrow<K1>>(k1: KArg1);
-
-	/// Mutate the value under a key.
-	fn mutate<KArg1, KArg2, R, F>(k1: KArg1, k2: KArg2, f: F) -> R
+	fn key_for<KArg1, KArg2>(k1: &KArg1, k2: &KArg2) -> Vec<u8>
 	where
-		KArg1: Borrow<K1>,
-		KArg2: Borrow<K2>,
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode;
+
+	fn prefix_for<KArg1>(k1: &KArg1) -> Vec<u8> where KArg1: ?Sized + Encode, K1: Borrow<KArg1>;
+
+	fn exists<KArg1, KArg2>(k1: &KArg1, k2: &KArg2) -> bool
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode;
+
+	fn get<KArg1, KArg2>(k1: &KArg1, k2: &KArg2) -> Self::Query
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode;
+
+	fn take<KArg1, KArg2>(k1: &KArg1, k2: &KArg2) -> Self::Query
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode;
+
+	fn insert<KArg1, KArg2, VArg>(k1: &KArg1, k2: &KArg2, val: &VArg)
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		V: Borrow<VArg>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
+		VArg: ?Sized + Encode;
+
+	fn remove<KArg1, KArg2>(k1: &KArg1, k2: &KArg2)
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode;
+
+	fn remove_prefix<KArg1>(k1: &KArg1) where KArg1: ?Sized + Encode, K1: Borrow<KArg1>;
+
+	fn mutate<KArg1, KArg2, R, F>(k1: &KArg1, k2: &KArg2, f: F) -> R
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
 		F: FnOnce(&mut Self::Query) -> R;
 
-	/// Append the given items to the value under the key specified.
-	///
-	/// `V` is required to implement `codec::EncodeAppend<Item=I>`.
 	fn append<KArg1, KArg2, I>(
-		k1: KArg1,
-		k2: KArg2,
+		k1: &KArg1,
+		k2: &KArg2,
 		items: &[I],
 	) -> Result<(), &'static str>
 	where
-		KArg1: Borrow<K1>,
-		KArg2: Borrow<K2>,
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
 		I: codec::Encode,
 		V: EncodeAppend<Item=I>;
 }
 
-impl<K1: Codec, K2: Codec, V: Codec, U> StorageDoubleMap<K1, K2, V> for U
+impl<K1: Encode, K2: Encode, V: Codec, U> StorageDoubleMap<K1, K2, V> for U
 where
 	U: unhashed::generator::StorageDoubleMap<K1, K2, V>
 {
@@ -395,59 +418,101 @@ where
 		<U as unhashed::generator::StorageDoubleMap<K1, K2, V>>::prefix()
 	}
 
-	fn key_for<KArg1: Borrow<K1>, KArg2: Borrow<K2>>(k1: KArg1, k2: KArg2) -> Vec<u8> {
-		<U as unhashed::generator::StorageDoubleMap<K1, K2, V>>::key_for(k1.borrow(), k2.borrow())
+	fn key_for<KArg1, KArg2>(k1: &KArg1, k2: &KArg2) -> Vec<u8>
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
+	{
+		<U as unhashed::generator::StorageDoubleMap<K1, K2, V>>::key_for(k1, k2)
 	}
 
-	fn prefix_for<KArg1: Borrow<K1>>(k1: KArg1) -> Vec<u8> {
-		<U as unhashed::generator::StorageDoubleMap<K1, K2, V>>::prefix_for(k1.borrow())
+	fn prefix_for<KArg1>(k1: &KArg1) -> Vec<u8> where KArg1: ?Sized + Encode, K1: Borrow<KArg1> {
+		<U as unhashed::generator::StorageDoubleMap<K1, K2, V>>::prefix_for(k1)
 	}
 
-	fn exists<KArg1: Borrow<K1>, KArg2: Borrow<K2>>(k1: KArg1, k2: KArg2) -> bool {
-		U::exists(k1.borrow(), k2.borrow(), &RuntimeStorage)
+	fn exists<KArg1, KArg2>(k1: &KArg1, k2: &KArg2) -> bool
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
+	{
+		U::exists(k1, k2, &RuntimeStorage)
 	}
 
-	fn get<KArg1: Borrow<K1>, KArg2: Borrow<K2>>(k1: KArg1, k2: KArg2) -> Self::Query {
-		U::get(k1.borrow(), k2.borrow(), &RuntimeStorage)
+	fn get<KArg1, KArg2>(k1: &KArg1, k2: &KArg2) -> Self::Query
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
+	{
+		U::get(k1, k2, &RuntimeStorage)
 	}
 
-	fn take<KArg1: Borrow<K1>, KArg2: Borrow<K2>>(k1: KArg1, k2: KArg2) -> Self::Query {
+	fn take<KArg1, KArg2>(k1: &KArg1, k2: &KArg2) -> Self::Query
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
+	{
 		U::take(k1.borrow(), k2.borrow(), &mut RuntimeStorage)
 	}
 
-	fn insert<KArg1: Borrow<K1>, KArg2: Borrow<K2>, VArg: Borrow<V>>(k1: KArg1, k2: KArg2, val: VArg) {
-		U::insert(k1.borrow(), k2.borrow(), val.borrow(), &mut RuntimeStorage)
-	}
-
-	fn remove<KArg1: Borrow<K1>, KArg2: Borrow<K2>>(k1: KArg1, k2: KArg2) {
-		U::remove(k1.borrow(), k2.borrow(), &mut RuntimeStorage)
-	}
-
-	fn remove_prefix<KArg1: Borrow<K1>>(k1: KArg1) {
-		U::remove_prefix(k1.borrow(), &mut RuntimeStorage)
-	}
-
-	fn mutate<KArg1, KArg2, R, F>(k1: KArg1, k2: KArg2, f: F) -> R
+	fn insert<KArg1, KArg2, VArg>(k1: &KArg1, k2: &KArg2, val: &VArg)
 	where
-		KArg1: Borrow<K1>,
-		KArg2: Borrow<K2>,
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		V: Borrow<VArg>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
+		VArg: ?Sized + Encode,
+	{
+		U::insert(k1, k2, val, &mut RuntimeStorage)
+	}
+
+	fn remove<KArg1, KArg2>(k1: &KArg1, k2: &KArg2)
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
+	{
+		U::remove(k1, k2, &mut RuntimeStorage)
+	}
+
+	fn remove_prefix<KArg1>(k1: &KArg1) where KArg1: ?Sized + Encode, K1: Borrow<KArg1> {
+		U::remove_prefix(k1, &mut RuntimeStorage)
+	}
+
+	fn mutate<KArg1, KArg2, R, F>(k1: &KArg1, k2: &KArg2, f: F) -> R
+	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
 		F: FnOnce(&mut Self::Query) -> R
 	{
-		U::mutate(k1.borrow(), k2.borrow(), f, &mut RuntimeStorage)
+		U::mutate(k1, k2, f, &mut RuntimeStorage)
 	}
 
 	fn append<KArg1, KArg2, I>(
-		k1: KArg1,
-		k2: KArg2,
+		k1: &KArg1,
+		k2: &KArg2,
 		items: &[I],
 	) -> Result<(), &'static str>
 	where
-		KArg1: Borrow<K1>,
-		KArg2: Borrow<K2>,
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
 		I: codec::Encode,
 		V: EncodeAppend<Item=I>,
 	{
-		U::append(k1.borrow(), k2.borrow(), items, &mut RuntimeStorage)
+		U::append(k1, k2, items, &mut RuntimeStorage)
 	}
 }
 
diff --git a/substrate/srml/support/src/storage/unhashed/generator.rs b/substrate/srml/support/src/storage/unhashed/generator.rs
index 3c56ae0ac5..26cb4b73e5 100644
--- a/substrate/srml/support/src/storage/unhashed/generator.rs
+++ b/substrate/srml/support/src/storage/unhashed/generator.rs
@@ -14,8 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-use crate::codec;
-use crate::rstd::vec::Vec;
+use crate::codec::{self, Encode, EncodeAppend};
+use crate::rstd::{borrow::Borrow, vec::Vec};
 
 /// Abstraction around storage with unhashed access.
 pub trait UnhashedStorage {
@@ -38,7 +38,7 @@ pub trait UnhashedStorage {
 	}
 
 	/// Put a value in under a key.
-	fn put<T: codec::Encode>(&mut self, key: &[u8], val: &T);
+	fn put<T: codec::Encode + ?Sized>(&mut self, key: &[u8], val: &T);
 
 	/// Remove the bytes of a key from storage.
 	fn kill(&mut self, key: &[u8]);
@@ -82,7 +82,7 @@ impl UnhashedStorage for sr_primitives::StorageOverlay {
 			.map(|x| codec::Decode::decode(&mut x.as_slice()).expect("Unable to decode expected type."))
 	}
 
-	fn put<T: codec::Encode>(&mut self, key: &[u8], val: &T) {
+	fn put<T: codec::Encode + ?Sized>(&mut self, key: &[u8], val: &T) {
 		self.insert(key.to_vec(), codec::Encode::encode(val));
 	}
 
@@ -117,7 +117,7 @@ impl UnhashedStorage for sr_primitives::StorageOverlay {
 /// is a hash of a `Key2`.
 ///
 /// /!\ be careful while choosing the Hash, indeed malicious could craft second keys to lower the trie.
-pub trait StorageDoubleMap<K1: codec::Codec, K2: codec::Codec, V: codec::Codec> {
+pub trait StorageDoubleMap<K1: codec::Encode, K2: codec::Encode, V: codec::Codec> {
 	/// The type that get/take returns.
 	type Query;
 
@@ -125,50 +125,110 @@ pub trait StorageDoubleMap<K1: codec::Codec, K2: codec::Codec, V: codec::Codec>
 	fn prefix() -> &'static [u8];
 
 	/// Get the storage key used to fetch a value corresponding to a specific key.
-	fn key_for(k1: &K1, k2: &K2) -> Vec<u8>;
+	fn key_for<KArg1, KArg2>(
+		k1: &KArg1,
+		k2: &KArg2,
+	) -> Vec<u8> where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode;
 
 	/// Get the storage prefix used to fetch keys corresponding to a specific key1.
-	fn prefix_for(k1: &K1) -> Vec<u8>;
+	fn prefix_for<KArg1>(k1: &KArg1) -> Vec<u8> where KArg1: ?Sized + Encode, K1: Borrow<KArg1>;
 
 	/// true if the value is defined in storage.
-	fn exists<S: UnhashedStorage>(k1: &K1, k2: &K2, storage: &S) -> bool {
+	fn exists<KArg1, KArg2, S: UnhashedStorage>(
+		k1: &KArg1,
+		k2: &KArg2,
+		storage: &S,
+	) -> bool where K1: Borrow<KArg1>, K2: Borrow<KArg2>, KArg1: ?Sized + Encode, KArg2: ?Sized + Encode {
 		storage.exists(&Self::key_for(k1, k2))
 	}
 
 	/// Load the value associated with the given key from the map.
-	fn get<S: UnhashedStorage>(k1: &K1, k2: &K2, storage: &S) -> Self::Query;
+	fn get<KArg1, KArg2, S: UnhashedStorage>(
+		k1: &KArg1,
+		k2: &KArg2,
+		storage: &S,
+	) -> Self::Query where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode;
 
 	/// Take the value under a key.
-	fn take<S: UnhashedStorage>(k1: &K1, k2: &K2, storage: &mut S) -> Self::Query;
+	fn take<KArg1, KArg2, S: UnhashedStorage>(
+		k1: &KArg1,
+		k2: &KArg2,
+		storage: &mut S,
+	) -> Self::Query where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode;
 
 	/// Store a value to be associated with the given key from the map.
-	fn insert<S: UnhashedStorage>(k1: &K1, k2: &K2, val: &V, storage: &mut S) {
+	fn insert<KArg1, KArg2, VArg, S: UnhashedStorage>(
+		k1: &KArg1,
+		k2: &KArg2,
+		val: &VArg,
+		storage: &mut S,
+	) where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		V: Borrow<VArg>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
+		VArg: ?Sized + Encode,
+	{
 		storage.put(&Self::key_for(k1, k2), val);
 	}
 
 	/// Remove the value under a key.
-	fn remove<S: UnhashedStorage>(k1: &K1, k2: &K2, storage: &mut S) {
+	fn remove<KArg1, KArg2, S: UnhashedStorage>(
+		k1: &KArg1,
+		k2: &KArg2,
+		storage: &mut S,
+	) where K1: Borrow<KArg1>, K2: Borrow<KArg2>, KArg1: ?Sized + Encode, KArg2: ?Sized + Encode {
 		storage.kill(&Self::key_for(k1, k2));
 	}
 
 	/// Removes all entries that shares the `k1` as the first key.
-	fn remove_prefix<S: UnhashedStorage>(k1: &K1, storage: &mut S) {
+	fn remove_prefix<KArg1, S: UnhashedStorage>(
+		k1: &KArg1,
+		storage: &mut S,
+	) where KArg1: ?Sized + Encode, K1: Borrow<KArg1> {
 		storage.kill_prefix(&Self::prefix_for(k1));
 	}
 
 	/// Mutate the value under a key.
-	fn mutate<R, F: FnOnce(&mut Self::Query) -> R, S: UnhashedStorage>(k1: &K1, k2: &K2, f: F, storage: &mut S) -> R;
+	fn mutate<KArg1, KArg2, R, F, S: UnhashedStorage>(
+		k1: &KArg1,
+		k2: &KArg2,
+		f: F,
+		storage: &mut S,
+	) -> R where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
+		F: FnOnce(&mut Self::Query) -> R;
 
 	/// Append the given items to the value under the key specified.
-	fn append<I, S: UnhashedStorage>(
-		k1: &K1,
-		k2: &K2,
+	fn append<KArg1, KArg2, I, S: UnhashedStorage>(
+		k1: &KArg1,
+		k2: &KArg2,
 		items: &[I],
 		storage: &mut S,
 	) -> Result<(), &'static str>
 	where
+		K1: Borrow<KArg1>,
+		K2: Borrow<KArg2>,
+		KArg1: ?Sized + Encode,
+		KArg2: ?Sized + Encode,
 		I: codec::Encode,
-		V: codec::EncodeAppend<Item=I>,
+		V: EncodeAppend<Item=I>,
 	{
 		let key = Self::key_for(k1, k2);
 		let new_val = <V as codec::EncodeAppend>::append(
diff --git a/substrate/srml/support/src/storage/unhashed/mod.rs b/substrate/srml/support/src/storage/unhashed/mod.rs
index 40e18d0cd2..77e6c2b37b 100644
--- a/substrate/srml/support/src/storage/unhashed/mod.rs
+++ b/substrate/srml/support/src/storage/unhashed/mod.rs
@@ -51,7 +51,7 @@ pub fn get_or_else<T: Decode + Sized, F: FnOnce() -> T>(key: &[u8], default_valu
 }
 
 /// Put `value` in storage under `key`.
-pub fn put<T: Encode>(key: &[u8], value: &T) {
+pub fn put<T: Encode + ?Sized>(key: &[u8], value: &T) {
 	value.using_encoded(|slice| runtime_io::set_storage(key, slice));
 }
 
diff --git a/substrate/srml/support/test/tests/final_keys.rs b/substrate/srml/support/test/tests/final_keys.rs
index 888ef48cb2..54c08d5e5f 100644
--- a/substrate/srml/support/test/tests/final_keys.rs
+++ b/substrate/srml/support/test/tests/final_keys.rs
@@ -29,7 +29,7 @@ srml_support::decl_module! {
 }
 
 srml_support::decl_storage!{
-	trait Store for Module<T: Trait> as Module {
+	trait Store for Module<T: Trait> as FinalKeys {
 		pub Value config(value): u32;
 
 		pub Map: map u32 => u32;
@@ -60,37 +60,37 @@ fn new_test_ext() -> runtime_io::TestExternalities<Blake2Hasher> {
 fn final_keys() {
 	with_externalities(&mut new_test_ext(), || {
 		Value::put(1);
-		assert_eq!(unhashed::get::<u32>(&runtime_io::twox_128(b"Module Value")), Some(1u32));
+		assert_eq!(unhashed::get::<u32>(&runtime_io::twox_128(b"FinalKeys Value")), Some(1u32));
 
 		Map::insert(1, 2);
-		let mut k = b"Module Map".to_vec();
+		let mut k = b"FinalKeys Map".to_vec();
 		k.extend(1u32.encode());
 		assert_eq!(unhashed::get::<u32>(&runtime_io::blake2_256(&k)), Some(2u32));
 
 		Map2::insert(1, 2);
-		let mut k = b"Module Map2".to_vec();
+		let mut k = b"FinalKeys Map2".to_vec();
 		k.extend(1u32.encode());
 		assert_eq!(unhashed::get::<u32>(&runtime_io::twox_128(&k)), Some(2u32));
 
 		LinkedMap::insert(1, 2);
-		let mut k = b"Module LinkedMap".to_vec();
+		let mut k = b"FinalKeys LinkedMap".to_vec();
 		k.extend(1u32.encode());
 		assert_eq!(unhashed::get::<u32>(&runtime_io::blake2_256(&k)), Some(2u32));
 
 		LinkedMap2::insert(1, 2);
-		let mut k = b"Module LinkedMap2".to_vec();
+		let mut k = b"FinalKeys LinkedMap2".to_vec();
 		k.extend(1u32.encode());
 		assert_eq!(unhashed::get::<u32>(&runtime_io::twox_128(&k)), Some(2u32));
 
-		DoubleMap::insert(1, 2, 3);
-		let mut k = b"Module DoubleMap".to_vec();
+		DoubleMap::insert(&1, &2, &3);
+		let mut k = b"FinalKeys DoubleMap".to_vec();
 		k.extend(1u32.encode());
 		let mut k = runtime_io::blake2_256(&k).to_vec();
 		k.extend(&runtime_io::blake2_256(&2u32.encode()));
 		assert_eq!(unhashed::get::<u32>(&k), Some(3u32));
 
-		DoubleMap2::insert(1, 2, 3);
-		let mut k = b"Module DoubleMap2".to_vec();
+		DoubleMap2::insert(&1, &2, &3);
+		let mut k = b"FinalKeys DoubleMap2".to_vec();
 		k.extend(1u32.encode());
 		let mut k = runtime_io::twox_128(&k).to_vec();
 		k.extend(&runtime_io::blake2_128(&2u32.encode()));
diff --git a/substrate/srml/support/test/tests/instance.rs b/substrate/srml/support/test/tests/instance.rs
index a5f40878e0..4702105bba 100644
--- a/substrate/srml/support/test/tests/instance.rs
+++ b/substrate/srml/support/test/tests/instance.rs
@@ -335,14 +335,14 @@ fn storage_instance_independance() {
 			module2::LinkedMap::<module2::Instance1>::key_for(1).to_vec(),
 			module2::LinkedMap::<module2::Instance2>::key_for(1).to_vec(),
 			module2::LinkedMap::<module2::Instance3>::key_for(1).to_vec(),
-			module2::DoubleMap::<module2::DefaultInstance>::prefix_for(1),
-			module2::DoubleMap::<module2::Instance1>::prefix_for(1).to_vec(),
-			module2::DoubleMap::<module2::Instance2>::prefix_for(1).to_vec(),
-			module2::DoubleMap::<module2::Instance3>::prefix_for(1).to_vec(),
-			module2::DoubleMap::<module2::DefaultInstance>::key_for(1, 1),
-			module2::DoubleMap::<module2::Instance1>::key_for(1, 1).to_vec(),
-			module2::DoubleMap::<module2::Instance2>::key_for(1, 1).to_vec(),
-			module2::DoubleMap::<module2::Instance3>::key_for(1, 1).to_vec(),
+			module2::DoubleMap::<module2::DefaultInstance>::prefix_for(&1),
+			module2::DoubleMap::<module2::Instance1>::prefix_for(&1).to_vec(),
+			module2::DoubleMap::<module2::Instance2>::prefix_for(&1).to_vec(),
+			module2::DoubleMap::<module2::Instance3>::prefix_for(&1).to_vec(),
+			module2::DoubleMap::<module2::DefaultInstance>::key_for(&1, &1),
+			module2::DoubleMap::<module2::Instance1>::key_for(&1, &1).to_vec(),
+			module2::DoubleMap::<module2::Instance2>::key_for(&1, &1).to_vec(),
+			module2::DoubleMap::<module2::Instance3>::key_for(&1, &1).to_vec(),
 		].iter() {
 			assert!(map.insert(key, ()).is_none())
 		}
@@ -396,15 +396,15 @@ fn storage_with_instance_basic_operation() {
 
 		let key1 = 1;
 		let key2 = 1;
-		assert_eq!(DoubleMap::exists(0, 0), true);
-		assert_eq!(DoubleMap::exists(key1, key2), false);
-		DoubleMap::insert(key1, key2, 1);
-		assert_eq!(DoubleMap::get(key1, key2), 1);
-		assert_eq!(DoubleMap::take(key1, key2), 1);
-		assert_eq!(DoubleMap::get(key1, key2), 0);
-		DoubleMap::mutate(key1, key2, |a| *a=2);
-		assert_eq!(DoubleMap::get(key1, key2), 2);
-		DoubleMap::remove(key1, key2);
-		assert_eq!(DoubleMap::get(key1, key2), 0);
+		assert_eq!(DoubleMap::exists(&0, &0), true);
+		assert_eq!(DoubleMap::exists(&key1, &key2), false);
+		DoubleMap::insert(&key1, &key2, &1);
+		assert_eq!(DoubleMap::get(&key1, &key2), 1);
+		assert_eq!(DoubleMap::take(&key1, &key2), 1);
+		assert_eq!(DoubleMap::get(&key1, &key2), 0);
+		DoubleMap::mutate(&key1, &key2, |a| *a=2);
+		assert_eq!(DoubleMap::get(&key1, &key2), 2);
+		DoubleMap::remove(&key1, &key2);
+		assert_eq!(DoubleMap::get(&key1, &key2), 0);
 	});
 }