Migrate tx-graph, tx-pool and trie to the 2018 edition (#1611)

substrate/core/trie/src/lib.rs

@@ -18,20 +18,6 @@
 
 // TODO: no_std
 
-extern crate trie_root;
-extern crate parity_codec as codec;
-extern crate trie_db;
-extern crate hash_db;
-extern crate memory_db;
-
-#[cfg(test)]
-extern crate substrate_primitives;
-#[cfg(test)]
-extern crate trie_standardmap;
-#[cfg(test)]
-#[macro_use]
-extern crate hex_literal;
-
 mod error;
 mod node_header;
 mod node_codec;
@@ -281,6 +267,7 @@ mod tests {
 	use hash_db::{HashDB, Hasher};
 	use trie_db::{DBValue, TrieMut, Trie};
 	use trie_standardmap::{Alphabet, ValueMode, StandardMap};
+	use hex_literal::{hex, hex_impl};
 
 	fn check_equivalent(input: &Vec<(&[u8], &[u8])>) {
 		{

substrate/core/trie/src/node_codec.rs

@@ -20,7 +20,7 @@ use std::marker::PhantomData;
 use codec::{Encode, Decode, Compact};
 use hash_db::Hasher;
 use trie_db::{self, DBValue, NibbleSlice, node::Node, ChildReference};
-use error::Error;
+use crate::error::Error;
 use super::{EMPTY_TRIE, LEAF_NODE_OFFSET, LEAF_NODE_BIG, EXTENSION_NODE_OFFSET,
 	EXTENSION_NODE_BIG, take, partial_to_key, node_header::NodeHeader, branch_node};