diff --git a/Cargo.lock b/Cargo.lock
index c378eb1..468db50 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,14 +1,3 @@
-[root]
-name = "fatfs"
-version = "0.2.0"
-dependencies = [
- "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "byteorder 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "chrono 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "aho-corasick"
 version = "0.6.3"
@@ -45,6 +34,17 @@ dependencies = [
  "regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "fatfs"
+version = "0.2.0"
+dependencies = [
+ "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byteorder 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "chrono 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "kernel32-sys"
 version = "0.2.2"
diff --git a/examples/write.rs b/examples/write.rs
index c157299..2f5a0ae 100644
--- a/examples/write.rs
+++ b/examples/write.rs
@@ -2,7 +2,6 @@ extern crate fatfs;
 
 use std::fs::OpenOptions;
 use std::io::prelude::*;
-use std::str;
 
 use fatfs::{FileSystem, FsOptions, BufStream};
 
diff --git a/src/dir.rs b/src/dir.rs
index 74c159e..b5fb715 100644
--- a/src/dir.rs
+++ b/src/dir.rs
@@ -1,4 +1,3 @@
-use std::ascii::AsciiExt;
 use std::io::prelude::*;
 use std::io;
 use std::io::{ErrorKind, SeekFrom};
diff --git a/src/fs.rs b/src/fs.rs
index 6e63294..e0a965d 100644
--- a/src/fs.rs
+++ b/src/fs.rs
@@ -209,7 +209,7 @@ impl FsOptions {
     }
 }
 
-pub(crate) type FileSystemRef<'a, 'b: 'a> = &'a FileSystem<'b>;
+pub(crate) type FileSystemRef<'a, 'b> = &'a FileSystem<'b>;
 
 /// FAT filesystem main struct.
 pub struct FileSystem<'a> {