Use Rust 2018 syntax

Author: lrazovic

Cargo.toml

@@ -6,6 +6,7 @@ name = "subtle"
 # - update README if necessary by semver
 # - if any updates were made to the README, also update the module documentation in src/lib.rs
 version = "2.4.1"
+edition = "2018"
 authors = ["Isis Lovecruft <isis@patternsinthevoid.net>",
            "Henry de Valence <hdevalence@hdevalence.ca>"]
 readme = "README.md"

src/lib.rs

@@ -388,7 +388,6 @@ pub trait ConditionallySelectable: Copy {
     /// # Example
     ///
     /// ```
-    /// # extern crate subtle;
     /// use subtle::ConditionallySelectable;
     /// #
     /// # fn main() {
@@ -411,7 +410,6 @@ pub trait ConditionallySelectable: Copy {
     /// # Example
     ///
     /// ```
-    /// # extern crate subtle;
     /// use subtle::ConditionallySelectable;
     /// #
     /// # fn main() {
@@ -437,7 +435,6 @@ pub trait ConditionallySelectable: Copy {
     /// # Example
     ///
     /// ```
-    /// # extern crate subtle;
     /// use subtle::ConditionallySelectable;
     /// #
     /// # fn main() {
@@ -784,7 +781,6 @@ pub trait ConstantTimeGreater {
     /// # Example
     ///
     /// ```
-    /// # extern crate subtle;
     /// use subtle::ConstantTimeGreater;
     ///
     /// let x: u8 = 13;
@@ -868,7 +864,6 @@ pub trait ConstantTimeLess: ConstantTimeEq + ConstantTimeGreater {
     /// # Example
     ///
     /// ```
-    /// # extern crate subtle;
     /// use subtle::ConstantTimeLess;
     ///
     /// let x: u8 = 13;

tests/mod.rs

@@ -1,6 +1,3 @@
-extern crate rand;
-extern crate subtle;
-
 use rand::rngs::OsRng;
 use rand::RngCore;