diff --git a/secp256k1-sys/Cargo.toml b/secp256k1-sys/Cargo.toml
index 203011f..8993a16 100644
--- a/secp256k1-sys/Cargo.toml
+++ b/secp256k1-sys/Cargo.toml
@@ -13,6 +13,7 @@ keywords = [ "secp256k1", "libsecp256k1", "ffi" ]
 readme = "README.md"
 build = "build.rs"
 links = "rustsecp256k1_v0_5_0"
+edition = "2018"
 
 # Should make docs.rs show all functions, even those behind non-default features
 [package.metadata.docs.rs]
diff --git a/secp256k1-sys/src/lib.rs b/secp256k1-sys/src/lib.rs
index a681f98..d560ea6 100644
--- a/secp256k1-sys/src/lib.rs
+++ b/secp256k1-sys/src/lib.rs
@@ -17,10 +17,7 @@
 //! not be needed for most users.
 
 // Coding conventions
-#![deny(non_upper_case_globals)]
-#![deny(non_camel_case_types)]
-#![deny(non_snake_case)]
-#![deny(unused_mut)]
+#![deny(non_upper_case_globals, non_camel_case_types, non_snake_case, unused_mut)]
 
 #![cfg_attr(all(not(test), not(feature = "std")), no_std)]
 #![cfg_attr(docsrs, feature(doc_cfg))]
@@ -31,7 +28,6 @@ extern crate core;
 #[cfg(fuzzing)]
 const THIS_UNUSED_CONSTANT_IS_YOUR_WARNING_THAT_ALL_THE_CRYPTO_IN_THIS_LIB_IS_DISABLED_FOR_FUZZING: usize = 0;
 
-#[macro_use]
 mod macros;
 pub mod types;
 
diff --git a/secp256k1-sys/src/macros.rs b/secp256k1-sys/src/macros.rs
index 47f10df..10d715e 100644
--- a/secp256k1-sys/src/macros.rs
+++ b/secp256k1-sys/src/macros.rs
@@ -69,14 +69,14 @@ macro_rules! impl_array_newtype {
 
         impl PartialOrd for $thing {
             #[inline]
-            fn partial_cmp(&self, other: &$thing) -> Option<::core::cmp::Ordering> {
+            fn partial_cmp(&self, other: &$thing) -> Option<core::cmp::Ordering> {
                 self[..].partial_cmp(&other[..])
             }
         }
 
         impl Ord for $thing {
             #[inline]
-            fn cmp(&self, other: &$thing) -> ::core::cmp::Ordering {
+            fn cmp(&self, other: &$thing) -> core::cmp::Ordering {
                 self[..].cmp(&other[..])
             }
         }
@@ -89,7 +89,7 @@ macro_rules! impl_array_newtype {
             }
         }
 
-        impl ::core::ops::Index<usize> for $thing {
+        impl core::ops::Index<usize> for $thing {
             type Output = $ty;
 
             #[inline]
@@ -99,41 +99,41 @@ macro_rules! impl_array_newtype {
             }
         }
 
-        impl ::core::ops::Index<::core::ops::Range<usize>> for $thing {
+        impl core::ops::Index<core::ops::Range<usize>> for $thing {
             type Output = [$ty];
 
             #[inline]
-            fn index(&self, index: ::core::ops::Range<usize>) -> &[$ty] {
+            fn index(&self, index: core::ops::Range<usize>) -> &[$ty] {
                 let &$thing(ref dat) = self;
                 &dat[index]
             }
         }
 
-        impl ::core::ops::Index<::core::ops::RangeTo<usize>> for $thing {
+        impl core::ops::Index<core::ops::RangeTo<usize>> for $thing {
             type Output = [$ty];
 
             #[inline]
-            fn index(&self, index: ::core::ops::RangeTo<usize>) -> &[$ty] {
+            fn index(&self, index: core::ops::RangeTo<usize>) -> &[$ty] {
                 let &$thing(ref dat) = self;
                 &dat[index]
             }
         }
 
-        impl ::core::ops::Index<::core::ops::RangeFrom<usize>> for $thing {
+        impl core::ops::Index<core::ops::RangeFrom<usize>> for $thing {
             type Output = [$ty];
 
             #[inline]
-            fn index(&self, index: ::core::ops::RangeFrom<usize>) -> &[$ty] {
+            fn index(&self, index: core::ops::RangeFrom<usize>) -> &[$ty] {
                 let &$thing(ref dat) = self;
                 &dat[index]
             }
         }
 
-        impl ::core::ops::Index<::core::ops::RangeFull> for $thing {
+        impl core::ops::Index<core::ops::RangeFull> for $thing {
             type Output = [$ty];
 
             #[inline]
-            fn index(&self, _: ::core::ops::RangeFull) -> &[$ty] {
+            fn index(&self, _: core::ops::RangeFull) -> &[$ty] {
                 let &$thing(ref dat) = self;
                 &dat[..]
             }
@@ -142,7 +142,7 @@ macro_rules! impl_array_newtype {
             type Target = $ty;
             fn as_c_ptr(&self) -> *const Self::Target {
                 if self.is_empty() {
-                    ::core::ptr::null()
+                    core::ptr::null()
                 } else {
                     self.as_ptr()
                 }
@@ -150,7 +150,7 @@ macro_rules! impl_array_newtype {
 
             fn as_mut_c_ptr(&mut self) -> *mut Self::Target {
                 if self.is_empty() {
-                    ::core::ptr::null::<Self::Target>() as *mut _
+                    core::ptr::null::<Self::Target>() as *mut _
                 } else {
                     self.as_mut_ptr()
                 }
@@ -162,8 +162,8 @@ macro_rules! impl_array_newtype {
 #[macro_export]
 macro_rules! impl_raw_debug {
     ($thing:ident) => {
-        impl ::core::fmt::Debug for $thing {
-            fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
+        impl core::fmt::Debug for $thing {
+            fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
                 for i in self[..].iter().cloned() {
                     write!(f, "{:02x}", i)?;
                 }
diff --git a/secp256k1-sys/src/recovery.rs b/secp256k1-sys/src/recovery.rs
index 567f19d..99bb49c 100644
--- a/secp256k1-sys/src/recovery.rs
+++ b/secp256k1-sys/src/recovery.rs
@@ -15,9 +15,9 @@
 
 //! # FFI of the recovery module
 
-use ::types::*;
-use ::core::fmt;
-use {Context, Signature, NonceFn, PublicKey, CPtr};
+use crate::{Context, Signature, NonceFn, PublicKey, CPtr, impl_array_newtype};
+use crate::types::*;
+use core::fmt;
 
 /// Library-internal representation of a Secp256k1 signature + recovery ID
 #[repr(C)]
@@ -98,13 +98,10 @@ extern "C" {
 
 #[cfg(fuzzing)]
 mod fuzz_dummy {
-    use super::*;
-    use std::slice;
+    use core::slice;
 
-    use secp256k1_ec_pubkey_create;
-    use secp256k1_ec_pubkey_parse;
-    use secp256k1_ec_pubkey_serialize;
-    use SECP256K1_SER_COMPRESSED;
+    use crate::{secp256k1_ec_pubkey_create, secp256k1_ec_pubkey_parse, secp256k1_ec_pubkey_serialize, SECP256K1_SER_COMPRESSED};
+    use super::*;
 
     /// Sets sig to msg32||full pk
     pub unsafe fn secp256k1_ecdsa_sign_recoverable(
@@ -170,6 +167,6 @@ mod fuzz_dummy {
         1
     }
 }
-#[cfg(fuzzing)]
-pub use self::fuzz_dummy::*;
 
+#[cfg(fuzzing)]
+pub use self::fuzz_dummy::*;
\ No newline at end of file
diff --git a/secp256k1-sys/src/types.rs b/secp256k1-sys/src/types.rs
index e257d43..e2b9030 100644
--- a/secp256k1-sys/src/types.rs
+++ b/secp256k1-sys/src/types.rs
@@ -54,7 +54,7 @@ mod tests {
     use std::any::TypeId;
     use std::mem;
     use std::os::raw;
-    use {types, AlignedType};
+    use crate::{types, AlignedType};
 
     #[test]
     fn verify_types() {