diff --git a/src/hashdb.rs b/src/hashdb.rs
index eb41d23df..561c7843d 100644
--- a/src/hashdb.rs
+++ b/src/hashdb.rs
@@ -1,5 +1,4 @@
 use hash::*;
-use bytes::Bytes;
 
 pub trait HashDB {
 	/// Look up a given hash into the bytes that hash to it, returning None if the 
diff --git a/src/memorydb.rs b/src/memorydb.rs
index 58dc980ca..4ec02bd5e 100644
--- a/src/memorydb.rs
+++ b/src/memorydb.rs
@@ -104,9 +104,8 @@ impl MemoryDB {
 	pub fn denote(&self, key: &H256, value: Bytes) -> &(Bytes, i32) {
 		if self.data.get(&key) == None {
 			unsafe {
-				let p = &self.data as *const HashMap<H256, (Bytes, i32)>;
-				let mp = p as *mut HashMap<H256, (Bytes, i32)>;
-				(*mp).insert(key.clone(), (value, 0));
+				let p = &self.data as *const HashMap<H256, (Bytes, i32)> as *mut HashMap<H256, (Bytes, i32)>;
+				(*p).insert(key.clone(), (value, 0));
 			}
 		}
 		self.data.get(key).unwrap()
@@ -161,7 +160,7 @@ fn memorydb_denote() {
 	let hash = m.insert(hello_bytes);
 	assert_eq!(m.lookup(&hash).unwrap(), b"Hello world!");
 
-	for i in 0..1000 {
+	for _ in 0..1000 {
 		let r = H256::random();
 		let k = r.sha3();
 		let &(ref v, ref rc) = m.denote(&k, r.bytes().to_vec());
diff --git a/src/overlaydb.rs b/src/overlaydb.rs
index 86ad266c9..b6f2b3eb2 100644
--- a/src/overlaydb.rs
+++ b/src/overlaydb.rs
@@ -8,7 +8,6 @@ use hashdb::*;
 use memorydb::*;
 use std::ops::*;
 use std::sync::*;
-use std::cell::*;
 use std::env;
 use rocksdb::{DB, Writable};
 
diff --git a/src/trie.rs b/src/trie.rs
index 41c8f58ea..392e40a04 100644
--- a/src/trie.rs
+++ b/src/trie.rs
@@ -1,8 +1,8 @@
 use memorydb::*;
 use hashdb::*;
 use hash::*;
-use rlp::*;
-use bytes::*;
+//use rlp::*;
+//use bytes::*;
 
 pub const NULL_RLP: [u8; 1] = [0x80; 1];
 pub const SHA3_NULL_RLP: H256 = H256( [0x56, 0xe8, 0x1f, 0x17, 0x1b, 0xcc, 0x55, 0xa6, 0xff, 0x83, 0x45, 0xe6, 0x92, 0xc0, 0xf8, 0x6e, 0x5b, 0x48, 0xe0, 0x1b, 0x99, 0x6c, 0xad, 0xc0, 0x01, 0x62, 0x2f, 0xb5, 0xe3, 0x63, 0xb4, 0x21] );