diff --git a/poly1305/Cargo.toml b/poly1305/Cargo.toml
index 84ec37c..2378315 100644
--- a/poly1305/Cargo.toml
+++ b/poly1305/Cargo.toml
@@ -22,9 +22,48 @@ cpufeatures = "0.3"
 [dev-dependencies]
 hex-literal = "1"
 
+[lints.rust]
+missing_copy_implementations = "warn"
+missing_debug_implementations = "warn"
+missing_docs = "warn"
+trivial_casts = "warn"
+trivial_numeric_casts = "warn"
+unused_lifetimes = "warn"
+unused_qualifications = "warn"
+unreachable_pub = "warn"
+
 [lints.rust.unexpected_cfgs]
 level = "warn"
 check-cfg = [
     'cfg(fuzzing)',
     'cfg(poly1305_backend, values("soft"))'
 ]
+
+[lints.clippy]
+borrow_as_ptr = "warn"
+cast_lossless = "warn"
+cast_possible_truncation = "allow" # TODO(tarcieri): warn
+cast_possible_wrap = "warn"
+cast_precision_loss = "warn"
+cast_sign_loss = "warn"
+checked_conversions = "warn"
+from_iter_instead_of_collect = "warn"
+implicit_saturating_sub = "warn"
+manual_assert = "warn"
+map_unwrap_or = "warn"
+missing_errors_doc = "warn"
+missing_panics_doc = "warn"
+mod_module_files = "warn"
+must_use_candidate = "warn"
+needless_range_loop = "allow"
+ptr_as_ptr = "warn"
+redundant_closure_for_method_calls = "warn"
+ref_as_ptr = "warn"
+return_self_not_must_use = "warn"
+semicolon_if_nothing_returned = "warn"
+trivially_copy_pass_by_ref = "warn"
+std_instead_of_alloc = "warn"
+std_instead_of_core = "warn"
+undocumented_unsafe_blocks = "allow" # TODO(tarcieri): warn
+unnecessary_safety_comment = "warn"
+unwrap_used = "allow" # TODO(tarcieri): warn
diff --git a/poly1305/benches/poly1305.rs b/poly1305/benches/poly1305.rs
index c52ff25..2d469ca 100644
--- a/poly1305/benches/poly1305.rs
+++ b/poly1305/benches/poly1305.rs
@@ -1,3 +1,5 @@
+//! Poly1305 benchmarks.
+
 #![feature(test)]
 
 extern crate test;
diff --git a/poly1305/src/backend/autodetect.rs b/poly1305/src/backend/autodetect.rs
index aadef9f..5a8efa5 100644
--- a/poly1305/src/backend/autodetect.rs
+++ b/poly1305/src/backend/autodetect.rs
@@ -8,7 +8,7 @@ use core::mem::ManuallyDrop;
 
 cpufeatures::new!(avx2_cpuid, "avx2");
 
-pub struct State {
+pub(crate) struct State {
     inner: Inner,
     token: avx2_cpuid::InitToken,
 }
@@ -95,8 +95,8 @@ impl Clone for State {
 impl Drop for State {
     fn drop(&mut self) {
         use zeroize::Zeroize;
-        const SIZE: usize = core::mem::size_of::<State>();
-        let state = unsafe { &mut *(self as *mut State as *mut [u8; SIZE]) };
+        const SIZE: usize = size_of::<State>();
+        let state = unsafe { &mut *core::ptr::from_mut::<State>(self).cast::<[u8; SIZE]>() };
         state.zeroize();
     }
 }
diff --git a/poly1305/src/backend/avx2.rs b/poly1305/src/backend/avx2.rs
index 2ff18dd..1131b03 100644
--- a/poly1305/src/backend/avx2.rs
+++ b/poly1305/src/backend/avx2.rs
@@ -113,7 +113,7 @@ impl State {
             // finalization).
             let (m, r4) = SpacedMultiplier4x130::new(self.r1, self.r2);
 
-            self.initialized = Some(Initialized { p, m, r4 })
+            self.initialized = Some(Initialized { p, m, r4 });
         }
     }
 
diff --git a/poly1305/src/backend/avx2/helpers.rs b/poly1305/src/backend/avx2/helpers.rs
index 8b3b7c3..4631c45 100644
--- a/poly1305/src/backend/avx2/helpers.rs
+++ b/poly1305/src/backend/avx2/helpers.rs
@@ -18,11 +18,11 @@ const fn set02(x3: u8, x2: u8, x1: u8, x0: u8) -> i32 {
 
 /// Helper for Display impls of aligned values.
 fn write_130(f: &mut fmt::Formatter<'_>, limbs: [u32; 5]) -> fmt::Result {
-    let r0 = limbs[0] as u128;
-    let r1 = limbs[1] as u128;
-    let r2 = limbs[2] as u128;
-    let r3 = limbs[3] as u128;
-    let r4 = limbs[4] as u128;
+    let r0 = u128::from(limbs[0]);
+    let r1 = u128::from(limbs[1]);
+    let r2 = u128::from(limbs[2]);
+    let r3 = u128::from(limbs[3]);
+    let r4 = u128::from(limbs[4]);
 
     // Reduce into two u128s
     let l0 = r0 + (r1 << 26) + (r2 << 52) + (r3 << 78);
@@ -34,11 +34,11 @@ fn write_130(f: &mut fmt::Formatter<'_>, limbs: [u32; 5]) -> fmt::Result {
 
 /// Helper for Display impls of unreduced values.
 fn write_130_wide(f: &mut fmt::Formatter<'_>, limbs: [u64; 5]) -> fmt::Result {
-    let r0 = limbs[0] as u128;
-    let r1 = limbs[1] as u128;
-    let r2 = limbs[2] as u128;
-    let r3 = limbs[3] as u128;
-    let r4 = limbs[4] as u128;
+    let r0 = u128::from(limbs[0]);
+    let r1 = u128::from(limbs[1]);
+    let r2 = u128::from(limbs[2]);
+    let r3 = u128::from(limbs[3]);
+    let r4 = u128::from(limbs[4]);
 
     // Reduce into two u128s
     let l0 = r0 + (r1 << 26) + (r2 << 52);
@@ -53,7 +53,7 @@ fn write_130_wide(f: &mut fmt::Formatter<'_>, limbs: [u64; 5]) -> fmt::Result {
 #[target_feature(enable = "avx2")]
 pub(super) unsafe fn prepare_keys(key: &Key) -> (AdditionKey, PrecomputedMultiplier) {
     // [k7, k6, k5, k4, k3, k2, k1, k0]
-    let key = _mm256_loadu_si256(key.as_ptr() as *const _);
+    let key = _mm256_loadu_si256(key.as_ptr().cast());
 
     // Prepare addition key: [0, k7, 0, k6, 0, k5, 0, k4]
     let k = AdditionKey(_mm256_and_si256(
@@ -80,7 +80,7 @@ impl fmt::Display for Aligned130 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut v0 = [0u8; 32];
         unsafe {
-            _mm256_storeu_si256(v0.as_mut_ptr() as *mut _, self.0);
+            _mm256_storeu_si256(v0.as_mut_ptr().cast(), self.0);
         }
 
         write!(f, "Aligned130(")?;
@@ -106,7 +106,7 @@ impl Aligned130 {
         Aligned130::new(_mm256_or_si256(
             _mm256_and_si256(
                 // Load the 128-bit block into a 256-bit vector.
-                _mm256_castsi128_si256(_mm_loadu_si128(block.as_ptr() as *const _)),
+                _mm256_castsi128_si256(_mm_loadu_si128(block.as_ptr().cast())),
                 // Mask off the upper 128 bits (undefined by _mm256_castsi128_si256).
                 _mm256_set_epi64x(0, 0, -1, -1),
             ),
@@ -122,7 +122,7 @@ impl Aligned130 {
     pub(super) unsafe fn from_partial_block(block: &Block) -> Self {
         Aligned130::new(_mm256_and_si256(
             // Load the 128-bit block into a 256-bit vector.
-            _mm256_castsi128_si256(_mm_loadu_si128(block.as_ptr() as *const _)),
+            _mm256_castsi128_si256(_mm_loadu_si128(block.as_ptr().cast())),
             // Mask off the upper 128 bits (undefined by _mm256_castsi128_si256).
             _mm256_set_epi64x(0, 0, -1, -1),
         ))
@@ -419,8 +419,8 @@ impl fmt::Display for Unreduced130 {
         let mut v0 = [0u8; 32];
         let mut v1 = [0u8; 32];
         unsafe {
-            _mm256_storeu_si256(v0.as_mut_ptr() as *mut _, self.v0);
-            _mm256_storeu_si256(v1.as_mut_ptr() as *mut _, self.v1);
+            _mm256_storeu_si256(v0.as_mut_ptr().cast(), self.v0);
+            _mm256_storeu_si256(v1.as_mut_ptr().cast(), self.v1);
         }
 
         write!(f, "Unreduced130(")?;
@@ -899,9 +899,9 @@ impl fmt::Display for Aligned4x130 {
         let mut v1 = [0u8; 32];
         let mut v2 = [0u8; 32];
         unsafe {
-            _mm256_storeu_si256(v0.as_mut_ptr() as *mut _, self.v0);
-            _mm256_storeu_si256(v1.as_mut_ptr() as *mut _, self.v1);
-            _mm256_storeu_si256(v2.as_mut_ptr() as *mut _, self.v2);
+            _mm256_storeu_si256(v0.as_mut_ptr().cast(), self.v0);
+            _mm256_storeu_si256(v1.as_mut_ptr().cast(), self.v1);
+            _mm256_storeu_si256(v2.as_mut_ptr().cast(), self.v2);
         }
 
         writeln!(f, "Aligned4x130([")?;
@@ -967,8 +967,8 @@ impl Aligned4x130 {
     #[target_feature(enable = "avx2")]
     pub(super) unsafe fn from_blocks(src: &[Block; 4]) -> Self {
         let (lo, hi) = src.split_at(2);
-        let blocks_23 = _mm256_loadu_si256(hi.as_ptr() as *const _);
-        let blocks_01 = _mm256_loadu_si256(lo.as_ptr() as *const _);
+        let blocks_23 = _mm256_loadu_si256(hi.as_ptr().cast());
+        let blocks_01 = _mm256_loadu_si256(lo.as_ptr().cast());
 
         Self::from_loaded_blocks(blocks_01, blocks_23)
     }
@@ -978,8 +978,8 @@ impl Aligned4x130 {
     #[target_feature(enable = "avx2")]
     pub(super) unsafe fn from_par_blocks(src: &ParBlocks) -> Self {
         let (lo, hi) = src.split_at(2);
-        let blocks_23 = _mm256_loadu_si256(hi.as_ptr() as *const _);
-        let blocks_01 = _mm256_loadu_si256(lo.as_ptr() as *const _);
+        let blocks_23 = _mm256_loadu_si256(hi.as_ptr().cast());
+        let blocks_01 = _mm256_loadu_si256(lo.as_ptr().cast());
 
         Self::from_loaded_blocks(blocks_01, blocks_23)
     }
@@ -1598,11 +1598,11 @@ impl fmt::Display for Unreduced4x130 {
         let mut v3 = [0u8; 32];
         let mut v4 = [0u8; 32];
         unsafe {
-            _mm256_storeu_si256(v0.as_mut_ptr() as *mut _, self.v0);
-            _mm256_storeu_si256(v1.as_mut_ptr() as *mut _, self.v1);
-            _mm256_storeu_si256(v2.as_mut_ptr() as *mut _, self.v2);
-            _mm256_storeu_si256(v3.as_mut_ptr() as *mut _, self.v3);
-            _mm256_storeu_si256(v4.as_mut_ptr() as *mut _, self.v4);
+            _mm256_storeu_si256(v0.as_mut_ptr().cast(), self.v0);
+            _mm256_storeu_si256(v1.as_mut_ptr().cast(), self.v1);
+            _mm256_storeu_si256(v2.as_mut_ptr().cast(), self.v2);
+            _mm256_storeu_si256(v3.as_mut_ptr().cast(), self.v3);
+            _mm256_storeu_si256(v4.as_mut_ptr().cast(), self.v4);
         }
 
         writeln!(f, "Unreduced4x130([")?;
@@ -1986,7 +1986,7 @@ impl From<AdditionKey> for IntegerTag {
 impl IntegerTag {
     pub(super) fn write(self, tag: &mut [u8]) {
         unsafe {
-            _mm_storeu_si128(tag.as_mut_ptr() as *mut _, self.0);
+            _mm_storeu_si128(tag.as_mut_ptr().cast(), self.0);
         }
     }
 }
diff --git a/poly1305/src/lib.rs b/poly1305/src/lib.rs
index 25956fd..a327de1 100644
--- a/poly1305/src/lib.rs
+++ b/poly1305/src/lib.rs
@@ -4,7 +4,6 @@
     html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg",
     html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg"
 )]
-#![warn(missing_docs)]
 
 pub use universal_hash;
 
@@ -95,6 +94,7 @@ impl Poly1305 {
     /// Compute unpadded Poly1305 for the given input data.
     ///
     /// The main use case for this is XSalsa20Poly1305.
+    #[must_use]
     pub fn compute_unpadded(mut self, data: &[u8]) -> Tag {
         let (blocks, remaining) = Block::slice_as_chunks(data);
 
diff --git a/poly1305/tests/lib.rs b/poly1305/tests/lib.rs
index 583e79e..ccbe438 100644
--- a/poly1305/tests/lib.rs
+++ b/poly1305/tests/lib.rs
@@ -1,9 +1,11 @@
+//! Poly1305 integration tests.
+
+use core::iter::repeat_n;
 use hex_literal::hex;
 use poly1305::{
     Block, KEY_SIZE, Poly1305,
     universal_hash::{KeyInit, UniversalHash},
 };
-use std::iter::repeat_n;
 
 #[test]
 fn test_nacl_vector() {