diff --git a/trie-db/src/fatdb.rs b/trie-db/src/fatdb.rs
index e5d4a198..bcb317c8 100644
--- a/trie-db/src/fatdb.rs
+++ b/trie-db/src/fatdb.rs
@@ -53,11 +53,11 @@ where
 {
 	fn root(&self) -> &TrieHash<L> { self.raw.root() }
 
-	fn contains(&self, key: &[u8]) -> Result<bool, TrieHash<L>, CError<L>> {
+	fn contains(&mut self, key: &[u8]) -> Result<bool, TrieHash<L>, CError<L>> {
 		self.raw.contains(L::Hash::hash(key).as_ref())
 	}
 
-	fn get_with<'a, 'key, Q: Query<L::Hash>>(&'a self, key: &'key [u8], query: Q)
+	fn get_with<'a, 'key, Q: Query<L::Hash>>(&'a mut self, key: &'key [u8], query: Q)
 		-> Result<Option<Q::Item>, TrieHash<L>, CError<L>>
 		where 'a: 'key
 	{
diff --git a/trie-db/src/lib.rs b/trie-db/src/lib.rs
index 37bfe64e..a3c72aac 100644
--- a/trie-db/src/lib.rs
+++ b/trie-db/src/lib.rs
@@ -178,13 +178,13 @@ pub trait Trie<L: TrieLayout> {
 	fn is_empty(&self) -> bool { *self.root() == L::Codec::hashed_null_node() }
 
 	/// Does the trie contain a given key?
-	fn contains(&self, key: &[u8]) -> Result<bool, TrieHash<L>, CError<L>> {
-		self.get(key).map(|x| x.is_some() )
+	fn contains(&mut self, key: &[u8]) -> Result<bool, TrieHash<L>, CError<L>> {
+		self.get(key).map(|x| x.is_some())
 	}
 
 	/// What is the value of the given key in this trie?
 	fn get<'a, 'key>(
-		&'a self,
+		&'a mut self,
 		key: &'key [u8],
 	) -> Result<Option<DBValue>, TrieHash<L>, CError<L>> where 'a: 'key {
 		self.get_with(key, |v: &[u8]| v.to_vec() )
@@ -193,7 +193,7 @@ pub trait Trie<L: TrieLayout> {
 	/// Search for the key with the given query parameter. See the docs of the `Query`
 	/// trait for more details.
 	fn get_with<'a, 'key, Q: Query<L::Hash>>(
-		&'a self,
+		&'a mut self,
 		key: &'key [u8],
 		query: Q
 	) -> Result<Option<Q::Item>, TrieHash<L>, CError<L>> where 'a: 'key;
@@ -300,17 +300,26 @@ impl<'db, L: TrieLayout> Trie<L> for TrieKinds<'db, L> {
 		wrapper!(self, is_empty,)
 	}
 
-	fn contains(&self, key: &[u8]) -> Result<bool, TrieHash<L>, CError<L>> {
-		wrapper!(self, contains, key)
+	fn contains(&mut self, key: &[u8]) -> Result<bool, TrieHash<L>, CError<L>> {
+		match self {
+			TrieKinds::Generic(ref mut t) => t.contains(key),
+			TrieKinds::Secure(ref mut t) => t.contains(key),
+			TrieKinds::Fat(ref mut t) => t.contains(key),
+		}
 	}
 
 	fn get_with<'a, 'key, Q: Query<L::Hash>>(
-		&'a self, key: &'key [u8],
+		&'a mut self,
+		key: &'key [u8],
 		query: Q,
 	) -> Result<Option<Q::Item>, TrieHash<L>, CError<L>>
 		where 'a: 'key
 	{
-		wrapper!(self, get_with, key, query)
+		match self {
+			TrieKinds::Generic(ref mut t) => t.get_with(key, query),
+			TrieKinds::Secure(ref mut t) => t.get_with(key, query),
+			TrieKinds::Fat(ref mut t) => t.get_with(key, query),
+		}
 	}
 
 	fn iter<'a>(&'a self) -> Result<
diff --git a/trie-db/src/proof/generate.rs b/trie-db/src/proof/generate.rs
index 817e9333..08789dbe 100644
--- a/trie-db/src/proof/generate.rs
+++ b/trie-db/src/proof/generate.rs
@@ -218,7 +218,7 @@ impl<'a, C: NodeCodec> StackEntry<'a, C> {
 /// Generate a compact proof for key-value pairs in a trie given a set of keys.
 ///
 /// Assumes inline nodes have only inline children.
-pub fn generate_proof<'a, T, L, I, K>(trie: &T, keys: I)
+pub fn generate_proof<'a, T, L, I, K>(trie: &mut T, keys: I)
 									  -> TrieResult<Vec<Vec<u8>>, TrieHash<L>, CError<L>>
 	where
 		T: Trie<L>,
diff --git a/trie-db/src/sectriedb.rs b/trie-db/src/sectriedb.rs
index 8b047135..33362d14 100644
--- a/trie-db/src/sectriedb.rs
+++ b/trie-db/src/sectriedb.rs
@@ -60,12 +60,12 @@ where
 {
 	fn root(&self) -> &TrieHash<L> { self.raw.root() }
 
-	fn contains(&self, key: &[u8]) -> Result<bool, TrieHash<L>, CError<L>> {
+	fn contains(&mut self, key: &[u8]) -> Result<bool, TrieHash<L>, CError<L>> {
 		self.raw.contains(L::Hash::hash(key).as_ref())
 	}
 
 	fn get_with<'a, 'key, Q: Query<L::Hash>>(
-		&'a self,
+		&'a mut self,
 		key: &'key [u8],
 		query: Q,
 	) -> Result<Option<Q::Item>, TrieHash<L>, CError<L>>
diff --git a/trie-db/src/triedb.rs b/trie-db/src/triedb.rs
index 385f08f9..eb91ec08 100644
--- a/trie-db/src/triedb.rs
+++ b/trie-db/src/triedb.rs
@@ -153,7 +153,7 @@ where
 	fn root(&self) -> &TrieHash<L> { self.root }
 
 	fn get_with<'a, 'key, Q: Query<L::Hash>>(
-		&'a self,
+		&'a mut self,
 		key: &'key [u8],
 		query: Q,
 	) -> Result<Option<Q::Item>, TrieHash<L>, CError<L>>