diff --git a/Cargo.toml b/Cargo.toml
index b673280..fb06f60 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,6 +9,7 @@ license = "MIT/Apache-2.0"
 repository = "https://github.com/rust-num/num-traits"
 name = "num-traits"
 version = "0.2.8"
+edition = "2018"
 readme = "README.md"
 build = "build.rs"
 exclude = ["/ci/*", "/.travis.yml", "/bors.toml"]
diff --git a/src/bounds.rs b/src/bounds.rs
index a133d7a..c9ff749 100644
--- a/src/bounds.rs
+++ b/src/bounds.rs
@@ -95,8 +95,8 @@ fn wrapping_bounded() {
     macro_rules! test_wrapping_bounded {
         ($($t:ty)+) => {
             $(
-                assert_eq!(Wrapping::<$t>::min_value().0, <$t>::min_value());
-                assert_eq!(Wrapping::<$t>::max_value().0, <$t>::max_value());
+                assert_eq!(<Wrapping<$t> as Bounded>::min_value().0, <$t>::min_value());
+                assert_eq!(<Wrapping<$t> as Bounded>::max_value().0, <$t>::max_value());
             )+
         };
     }
@@ -110,8 +110,8 @@ fn wrapping_bounded_i128() {
     macro_rules! test_wrapping_bounded {
         ($($t:ty)+) => {
             $(
-                assert_eq!(Wrapping::<$t>::min_value().0, <$t>::min_value());
-                assert_eq!(Wrapping::<$t>::max_value().0, <$t>::max_value());
+                assert_eq!(<Wrapping<$t> as Bounded>::min_value().0, <$t>::min_value());
+                assert_eq!(<Wrapping<$t> as Bounded>::max_value().0, <$t>::max_value());
             )+
         };
     }
diff --git a/src/cast.rs b/src/cast.rs
index 20e9340..6022eff 100644
--- a/src/cast.rs
+++ b/src/cast.rs
@@ -6,7 +6,7 @@ use core::{i128, u128};
 use core::{i16, i32, i64, i8, isize};
 use core::{u16, u32, u64, u8, usize};
 
-use float::FloatCore;
+use crate::float::FloatCore;
 
 /// A generic trait for converting a value to a number.
 pub trait ToPrimitive {
diff --git a/src/float.rs b/src/float.rs
index c91233c..7d1ba9d 100644
--- a/src/float.rs
+++ b/src/float.rs
@@ -5,7 +5,7 @@ use core::ops::Neg;
 use core::f32;
 use core::f64;
 
-use {Num, NumCast, ToPrimitive};
+use crate::{Num, NumCast, ToPrimitive};
 
 /// Generic trait for floating point numbers that works with `no_std`.
 ///
@@ -1982,7 +1982,7 @@ mod tests {
 
     #[test]
     fn convert_deg_rad() {
-        use float::FloatCore;
+        use crate::float::FloatCore;
 
         for &(deg, rad) in &DEG_RAD_PAIRS {
             assert!((FloatCore::to_degrees(rad) - deg).abs() < 1e-6);
@@ -1998,7 +1998,7 @@ mod tests {
     #[test]
     fn convert_deg_rad_std() {
         for &(deg, rad) in &DEG_RAD_PAIRS {
-            use Float;
+            use crate::Float;
 
             assert!((Float::to_degrees(rad) - deg).abs() < 1e-6);
             assert!((Float::to_radians(deg) - rad).abs() < 1e-6);
diff --git a/src/int.rs b/src/int.rs
index 26d5a9a..39412ee 100644
--- a/src/int.rs
+++ b/src/int.rs
@@ -1,9 +1,9 @@
 use core::ops::{BitAnd, BitOr, BitXor, Not, Shl, Shr};
 
-use bounds::Bounded;
-use ops::checked::*;
-use ops::saturating::Saturating;
-use {Num, NumCast};
+use crate::bounds::Bounded;
+use crate::ops::checked::*;
+use crate::ops::saturating::Saturating;
+use crate::{Num, NumCast};
 
 /// Generic trait for primitive integers.
 ///
diff --git a/src/lib.rs b/src/lib.rs
index 172e714..4e4060d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -16,9 +16,7 @@
 
 #![doc(html_root_url = "https://docs.rs/num-traits/0.2")]
 #![deny(unconditional_recursion)]
-#![no_std]
-#[cfg(feature = "std")]
-extern crate std;
+#![cfg_attr(not(feature = "std"), no_std)]
 
 use core::fmt;
 use core::num::Wrapping;
diff --git a/src/pow.rs b/src/pow.rs
index daecb8e..b45dc4c 100644
--- a/src/pow.rs
+++ b/src/pow.rs
@@ -1,6 +1,6 @@
 use core::num::Wrapping;
 use core::ops::Mul;
-use {CheckedMul, One};
+use crate::{CheckedMul, One};
 
 /// Binary operator for raising a value to a power.
 pub trait Pow<RHS> {
diff --git a/src/real.rs b/src/real.rs
index 23ac6b8..7281637 100644
--- a/src/real.rs
+++ b/src/real.rs
@@ -1,6 +1,6 @@
 use std::ops::Neg;
 
-use {Float, Num, NumCast};
+use crate::{Float, Num, NumCast};
 
 // NOTE: These doctests have the same issue as those in src/float.rs.
 // They're testing the inherent methods directly, and not those of `Real`.
diff --git a/src/sign.rs b/src/sign.rs
index 26d44c5..26b4e25 100644
--- a/src/sign.rs
+++ b/src/sign.rs
@@ -1,8 +1,8 @@
 use core::num::Wrapping;
 use core::ops::Neg;
 
-use float::FloatCore;
-use Num;
+use crate::float::FloatCore;
+use crate::Num;
 
 /// Useful functions for signed numbers (i.e. numbers that can be negative).
 pub trait Signed: Sized + Num + Neg<Output = Self> {