diff --git a/Cargo.toml b/Cargo.toml
index b2cbf9134..a4fff779f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -430,3 +430,6 @@ unnecessary_box_returns = "warn"
 unnecessary_join = "warn"
 unnecessary_wraps = "warn"
 unnested_or_patterns = "warn"
+
+[lints]
+workspace = true
diff --git a/benches/execution.rs b/benches/execution.rs
index 0152de240..56d4fc4fc 100644
--- a/benches/execution.rs
+++ b/benches/execution.rs
@@ -1,10 +1,15 @@
+#![allow(clippy::iter_over_hash_type)]
+
+extern crate alloc;
+
+use core::hint::black_box;
 use criterion::{
     Bencher, BenchmarkGroup, BenchmarkId, Criterion, Throughput, criterion_group, criterion_main,
     measurement::WallTime,
 };
 use rustpython_compiler::Mode;
 use rustpython_vm::{Interpreter, PyResult, Settings};
-use std::{collections::HashMap, hint::black_box, path::Path};
+use std::{collections::HashMap, path::Path};
 
 /// `true` when the benchmarks are executed by the CodSpeed runner.
 ///
@@ -15,8 +20,8 @@ fn is_codspeed() -> bool {
     std::env::var_os("CODSPEED_ENV").is_some()
 }
 
-fn bench_cpython_code(b: &mut Bencher, source: &str) {
-    let c_str_source_head = std::ffi::CString::new(source).unwrap();
+fn bench_cpython_code(b: &mut Bencher<'_>, source: &str) {
+    let c_str_source_head = alloc::ffi::CString::new(source).unwrap();
     let c_str_source = c_str_source_head.as_c_str();
     pyo3::Python::attach(|py| {
         b.iter(|| {
@@ -27,7 +32,7 @@ fn bench_cpython_code(b: &mut Bencher, source: &str) {
     })
 }
 
-fn bench_rustpython_code(b: &mut Bencher, name: &str, source: &str) {
+fn bench_rustpython_code(b: &mut Bencher<'_>, name: &str, source: &str) {
     // NOTE: Take long time.
     let mut settings = Settings::default();
     settings.path_list.push("Lib/".to_string());
@@ -41,13 +46,17 @@ fn bench_rustpython_code(b: &mut Bencher, name: &str, source: &str) {
         b.iter(|| {
             let code = vm.compile(source, Mode::Exec, name).unwrap();
             let scope = vm.new_scope_with_builtins();
-            let res: PyResult = vm.run_code_obj(code.clone(), scope);
+            let res: PyResult = vm.run_code_obj(code, scope);
             vm.unwrap_pyresult(res);
         })
     })
 }
 
-pub fn benchmark_file_execution(group: &mut BenchmarkGroup<WallTime>, name: &str, contents: &str) {
+pub fn benchmark_file_execution(
+    group: &mut BenchmarkGroup<'_, WallTime>,
+    name: &str,
+    contents: &str,
+) {
     if !is_codspeed() {
         group.bench_function(BenchmarkId::new(name, "cpython"), |b| {
             bench_cpython_code(b, contents)
@@ -58,7 +67,11 @@ pub fn benchmark_file_execution(group: &mut BenchmarkGroup<WallTime>, name: &str
     });
 }
 
-pub fn benchmark_file_parsing(group: &mut BenchmarkGroup<WallTime>, name: &str, contents: &str) {
+pub fn benchmark_file_parsing(
+    group: &mut BenchmarkGroup<'_, WallTime>,
+    name: &str,
+    contents: &str,
+) {
     group.throughput(Throughput::Bytes(contents.len() as u64));
     group.bench_function(BenchmarkId::new("rustpython", name), |b| {
         b.iter(|| ruff_python_parser::parse_module(contents).unwrap())
@@ -81,7 +94,7 @@ pub fn benchmark_file_parsing(group: &mut BenchmarkGroup<WallTime>, name: &str,
     }
 }
 
-pub fn benchmark_pystone(group: &mut BenchmarkGroup<WallTime>, contents: String) {
+pub fn benchmark_pystone(group: &mut BenchmarkGroup<'_, WallTime>, contents: String) {
     // Default is 50_000. This takes a while, so reduce it to 30k.
     for idx in (10_000..=30_000).step_by(10_000) {
         let code_with_loops = format!("LOOPS = {idx}\n{contents}");
diff --git a/benches/microbenchmarks.rs b/benches/microbenchmarks.rs
index 9f7f70c02..4d48278e4 100644
--- a/benches/microbenchmarks.rs
+++ b/benches/microbenchmarks.rs
@@ -5,10 +5,7 @@ use criterion::{
 use pyo3::types::PyAnyMethods;
 use rustpython_compiler::Mode;
 use rustpython_vm::{AsObject, Interpreter, PyResult, Settings};
-use std::{
-    fs, io,
-    path::{Path, PathBuf},
-};
+use std::{fs, io, path::Path};
 
 // List of microbenchmarks to skip.
 //
@@ -36,7 +33,7 @@ pub struct MicroBenchmark {
     iterate: bool,
 }
 
-fn bench_cpython_code(group: &mut BenchmarkGroup<WallTime>, bench: &MicroBenchmark) {
+fn bench_cpython_code(group: &mut BenchmarkGroup<'_, WallTime>, bench: &MicroBenchmark) {
     pyo3::Python::attach(|py| {
         let setup_name = format!("{}_setup", bench.name);
         let setup_code = cpy_compile_code(py, &bench.setup, &setup_name).unwrap();
@@ -49,8 +46,8 @@ fn bench_cpython_code(group: &mut BenchmarkGroup<WallTime>, bench: &MicroBenchma
         let exec = builtins.getattr("exec").expect("no exec in builtins");
 
         let bench_func = |(globals, locals): &mut (
-            pyo3::Bound<pyo3::types::PyDict>,
-            pyo3::Bound<pyo3::types::PyDict>,
+            pyo3::Bound<'_, pyo3::types::PyDict>,
+            pyo3::Bound<'_, pyo3::types::PyDict>,
         )| {
             let res = exec.call((&code, &*globals, &*locals), None);
             if let Err(e) = res {
@@ -107,7 +104,7 @@ fn cpy_compile_code<'a>(
         .expect("compile() should return a code object"))
 }
 
-fn bench_rustpython_code(group: &mut BenchmarkGroup<WallTime>, bench: &MicroBenchmark) {
+fn bench_rustpython_code(group: &mut BenchmarkGroup<'_, WallTime>, bench: &MicroBenchmark) {
     let mut settings = Settings::default();
     settings.path_list.push("Lib/".to_string());
     settings.write_bytecode = false;
@@ -208,11 +205,11 @@ pub fn criterion_benchmark(c: &mut Criterion) {
         .unwrap()
         .collect::<io::Result<_>>()
         .unwrap();
-    let paths: Vec<PathBuf> = dirs.iter().map(|p| p.path()).collect();
 
-    let benchmarks: Vec<MicroBenchmark> = paths
-        .into_iter()
-        .map(|p| {
+    let benchmarks: Vec<MicroBenchmark> = dirs
+        .iter()
+        .map(|d| {
+            let p = d.path();
             let name = p.file_name().unwrap().to_os_string();
             let contents = fs::read_to_string(p).unwrap();
             let iterate = contents.contains("ITERATIONS");
diff --git a/crates/codegen/src/ir.rs b/crates/codegen/src/ir.rs
index 2c7aaedc0..790846a40 100644
--- a/crates/codegen/src/ir.rs
+++ b/crates/codegen/src/ir.rs
@@ -1253,8 +1253,7 @@ fn assemble_location_info(
     let mut prev_line = first_line;
     let mut loc = no_linetable_location();
     let mut size = 0;
-    for i in 0..instr_sequence.instr_used {
-        let entry = &instr_sequence.instrs[i];
+    for entry in instr_sequence.instrs.iter().take(instr_sequence.instr_used) {
         let instr_loc = entry.info.instruction_linetable_location();
         if !same_location(loc, instr_loc) {
             assemble_emit_location(&mut linetable, loc, size, &mut prev_line, debug_ranges)?;
@@ -2772,8 +2771,7 @@ impl Blocks {
         let mut block_idx = BlockIdx(0);
         while block_idx != BlockIdx::NULL {
             let block = &self[block_idx];
-            for i in 0..block.instruction_used {
-                let instr = &block.instructions[i];
+            for instr in block.instructions.iter().take(block.instruction_used) {
                 if instr.instr.has_const() {
                     let index = u32::from(instr.arg) as usize;
                     debug_assert!(index < nconsts);
@@ -6596,8 +6594,11 @@ fn cfg_from_instruction_sequence(
             if let Some(annotations_code) = &annotations_code {
                 debug_assert!(annotations_code.label_map.is_none());
                 debug_assert_eq!(annotations_code.label_map_allocation, 0);
-                for j in 0..annotations_code.instr_used {
-                    let ann_entry = annotations_code.instrs[j];
+                for ann_entry in annotations_code
+                    .instrs
+                    .iter()
+                    .take(annotations_code.instr_used)
+                {
                     debug_assert!(!ann_entry.info.instr.has_target());
                     let mut info = ann_entry.info;
                     info.target = BlockIdx::NULL;
diff --git a/crates/common/src/float_ops.rs b/crates/common/src/float_ops.rs
index ac4e6b0bf..f519cdaba 100644
--- a/crates/common/src/float_ops.rs
+++ b/crates/common/src/float_ops.rs
@@ -1,4 +1,4 @@
-use core::f64;
+use core::f64::consts::LOG10_2;
 use malachite_bigint::{BigInt, ToBigInt};
 use num_traits::{Signed, ToPrimitive};
 
@@ -240,9 +240,8 @@ pub fn round_float_digits(x: f64, ndigits: i32) -> Option<f64> {
         return Some(x);
     }
 
-    const NDIGITS_MAX: i32 =
-        ((f64::MANTISSA_DIGITS as i32 - f64::MIN_EXP) as f64 * f64::consts::LOG10_2) as i32;
-    const NDIGITS_MIN: i32 = -(((f64::MAX_EXP + 1) as f64 * f64::consts::LOG10_2) as i32);
+    const NDIGITS_MAX: i32 = ((f64::MANTISSA_DIGITS as i32 - f64::MIN_EXP) as f64 * LOG10_2) as i32;
+    const NDIGITS_MIN: i32 = -(((f64::MAX_EXP + 1) as f64 * LOG10_2) as i32);
 
     if ndigits > NDIGITS_MAX {
         return Some(x);
diff --git a/crates/common/src/wtf8_index.rs b/crates/common/src/wtf8_index.rs
index 4b2e5ebee..a45033d98 100644
--- a/crates/common/src/wtf8_index.rs
+++ b/crates/common/src/wtf8_index.rs
@@ -146,13 +146,13 @@ impl Wtf8Index {
         };
         let mut index = group_min << 6;
         let mut pos = base;
-        for entry in 0..entries {
-            let at = base + self.groups[group_min].ofs[entry] as usize;
+        for (i, &entry) in self.groups[group_min].ofs.iter().enumerate().take(entries) {
+            let at = base + entry as usize;
             if at >= bytepos {
                 break;
             }
             pos = at;
-            index = (group_min << 6) + (entry << 2) + 1;
+            index = (group_min << 6) + (i << 2) + 1;
         }
         while pos < bytepos {
             pos = next_pos(data, pos);
diff --git a/crates/host_env/Cargo.toml b/crates/host_env/Cargo.toml
index bf2cc2a71..8b3f0dd37 100644
--- a/crates/host_env/Cargo.toml
+++ b/crates/host_env/Cargo.toml
@@ -50,7 +50,7 @@ nix = { workspace = true }
 rustix = { workspace = true }
 
 [target.'cfg(any(not(target_arch = "wasm32"), target_os = "wasi"))'.dependencies]
-num_cpus = "1.17.0"
+num_cpus = { workspace = true }
 
 [target.'cfg(not(any(target_os = "ios", target_os = "android", target_os = "windows", target_arch = "wasm32", target_os = "redox")))'.dependencies]
 mac_address = { workspace = true }
@@ -67,8 +67,8 @@ which = { workspace = true }
 termios = { workspace = true }
 
 [target.'cfg(any(unix, windows))'.dependencies]
-memmap2 = "0.9.10"
-libloading = "0.9"
+memmap2 = { workspace = true }
+libloading = { workspace = true }
 
 [target.'cfg(all(any(target_os = "linux", target_os = "macos", target_os = "windows", target_os = "android"), not(any(target_env = "musl", target_env = "sgx"))))'.dependencies]
 libffi = { workspace = true, features = ["system"] }
diff --git a/crates/host_env/src/multiprocessing.rs b/crates/host_env/src/multiprocessing.rs
index 255369f7c..f61a136e9 100644
--- a/crates/host_env/src/multiprocessing.rs
+++ b/crates/host_env/src/multiprocessing.rs
@@ -179,10 +179,11 @@ impl SemHandle {
 
     /// A handle rebuilt from the integer a `SemLock` stored.
     ///
+    /// # Safety
     /// `Drop` closes the semaphore. A caller that still owns that close
     /// must forget this value.
     #[inline]
-    pub unsafe fn from_raw(raw: *mut sem_t) -> Self {
+    pub const unsafe fn from_raw(raw: *mut sem_t) -> Self {
         Self { raw }
     }
 
diff --git a/crates/host_env/src/os.rs b/crates/host_env/src/os.rs
index e37dd1d0c..6678572bf 100644
--- a/crates/host_env/src/os.rs
+++ b/crates/host_env/src/os.rs
@@ -235,7 +235,6 @@ pub fn rename(
 ///
 /// On Windows, this supports the full u32 range including STATUS_CONTROL_C_EXIT (0xC000013A).
 /// On other platforms, only the lower 8 bits are used.
-#[must_use]
 pub fn exit_code(code: u32) -> ExitCode {
     #[cfg(windows)]
     {
diff --git a/crates/literal/Cargo.toml b/crates/literal/Cargo.toml
index 60350f793..2a80fc633 100644
--- a/crates/literal/Cargo.toml
+++ b/crates/literal/Cargo.toml
@@ -8,6 +8,9 @@ repository = { workspace = true }
 license = { workspace = true }
 rust-version = { workspace = true }
 
+[lints]
+workspace = true
+
 [dependencies]
 rustpython-unicode = { workspace = true }
 rustpython-wtf8 = { workspace = true }
diff --git a/crates/literal/src/complex.rs b/crates/literal/src/complex.rs
index bc193f0f2..78f3fc023 100644
--- a/crates/literal/src/complex.rs
+++ b/crates/literal/src/complex.rs
@@ -33,6 +33,7 @@ fn component_to_string(value: f64) -> String {
 }
 
 /// Convert a complex number to a string.
+#[must_use]
 pub fn to_string(re: f64, im: f64) -> String {
     let mut im_part = component_to_string(im);
     im_part.push('j');
@@ -41,9 +42,8 @@ pub fn to_string(re: f64, im: f64) -> String {
     let re_part = if re == 0.0 {
         if re.is_sign_positive() {
             return im_part;
-        } else {
-            "-0".to_owned()
         }
+        "-0".to_owned()
     } else {
         component_to_string(re)
     };
diff --git a/crates/literal/src/escape.rs b/crates/literal/src/escape.rs
index 50dce8b26..29f0e82bc 100644
--- a/crates/literal/src/escape.rs
+++ b/crates/literal/src/escape.rs
@@ -9,6 +9,7 @@ pub enum Quote {
 
 impl Quote {
     #[inline]
+    #[must_use]
     pub const fn swap(self) -> Self {
         match self {
             Self::Single => Self::Double,
@@ -17,6 +18,7 @@ impl Quote {
     }
 
     #[inline]
+    #[must_use]
     pub const fn to_byte(&self) -> u8 {
         match self {
             Self::Single => b'\'',
@@ -25,6 +27,7 @@ impl Quote {
     }
 
     #[inline]
+    #[must_use]
     pub const fn to_char(&self) -> char {
         match self {
             Self::Single => '\'',
@@ -96,20 +99,24 @@ pub struct UnicodeEscape<'a> {
 
 impl<'a> UnicodeEscape<'a> {
     #[inline]
+    #[must_use]
     pub const fn with_forced_quote(source: &'a Wtf8, quote: Quote) -> Self {
         let layout = EscapeLayout { quote, len: None };
         Self { source, layout }
     }
     #[inline]
+    #[must_use]
     pub fn with_preferred_quote(source: &'a Wtf8, quote: Quote) -> Self {
         let layout = Self::repr_layout(source, quote);
         Self { source, layout }
     }
     #[inline]
+    #[must_use]
     pub fn new_repr(source: &'a Wtf8) -> Self {
         Self::with_preferred_quote(source, Quote::Single)
     }
     #[inline]
+    #[must_use]
     pub const fn str_repr<'r>(&'a self) -> StrRepr<'r, 'a> {
         StrRepr(self)
     }
@@ -125,6 +132,7 @@ impl StrRepr<'_, '_> {
         formatter.write_char(quote)
     }
 
+    #[must_use]
     pub fn to_string(&self) -> Option<String> {
         let mut s = String::with_capacity(self.0.layout().len?);
         self.write(&mut s).unwrap();
@@ -141,6 +149,7 @@ impl core::fmt::Display for StrRepr<'_, '_> {
 impl UnicodeEscape<'_> {
     const REPR_RESERVED_LEN: usize = 2; // for quotes
 
+    #[must_use]
     pub fn repr_layout(source: &Wtf8, preferred_quote: Quote) -> EscapeLayout {
         Self::output_layout_with_checker(source, preferred_quote, |a, b| {
             Some((a as isize).checked_add(b as isize)? as usize)
@@ -284,36 +293,43 @@ pub struct AsciiEscape<'a> {
 
 impl<'a> AsciiEscape<'a> {
     #[inline]
+    #[must_use]
     pub const fn new(source: &'a [u8], layout: EscapeLayout) -> Self {
         Self { source, layout }
     }
     #[inline]
+    #[must_use]
     pub const fn with_forced_quote(source: &'a [u8], quote: Quote) -> Self {
         let layout = EscapeLayout { quote, len: None };
         Self { source, layout }
     }
     #[inline]
+    #[must_use]
     pub fn with_preferred_quote(source: &'a [u8], quote: Quote) -> Self {
         let layout = Self::repr_layout(source, quote);
         Self { source, layout }
     }
     #[inline]
+    #[must_use]
     pub fn new_repr(source: &'a [u8]) -> Self {
         Self::with_preferred_quote(source, Quote::Single)
     }
     #[inline]
+    #[must_use]
     pub const fn bytes_repr<'r>(&'a self) -> BytesRepr<'r, 'a> {
         BytesRepr(self)
     }
 }
 
 impl AsciiEscape<'_> {
+    #[must_use]
     pub fn repr_layout(source: &[u8], preferred_quote: Quote) -> EscapeLayout {
         Self::output_layout_with_checker(source, preferred_quote, 3, |a, b| {
             Some((a as isize).checked_add(b as isize)? as usize)
         })
     }
 
+    #[must_use]
     pub fn named_repr_layout(source: &[u8], name: &str) -> EscapeLayout {
         Self::output_layout_with_checker(source, Quote::Single, name.len() + 2 + 3, |a, b| {
             Some((a as isize).checked_add(b as isize)? as usize)
@@ -436,6 +452,7 @@ impl BytesRepr<'_, '_> {
         formatter.write_char(quote)
     }
 
+    #[must_use]
     pub fn to_string(&self) -> Option<String> {
         let mut s = String::with_capacity(self.0.layout().len?);
         self.write(&mut s).unwrap();
diff --git a/crates/literal/src/float.rs b/crates/literal/src/float.rs
index 2db4fd084..8a0a18fc9 100644
--- a/crates/literal/src/float.rs
+++ b/crates/literal/src/float.rs
@@ -2,13 +2,14 @@ use crate::format::Case;
 use alloc::borrow::ToOwned;
 use alloc::format;
 use alloc::string::{String, ToString};
-use core::f64;
 use num_traits::Zero;
 
+#[must_use]
 pub fn parse_str(literal: &str) -> Option<f64> {
     parse_inner(literal.trim().as_bytes())
 }
 
+#[must_use]
 pub fn parse_bytes(literal: &[u8]) -> Option<f64> {
     parse_inner(literal.trim_ascii())
 }
@@ -25,6 +26,7 @@ fn parse_inner(literal: &[u8]) -> Option<f64> {
     f64::from_lexical_with_options::<PYTHON_STRING>(literal, &Options::new()).ok()
 }
 
+#[must_use]
 pub fn is_integer(v: f64) -> bool {
     v.is_finite() && v.fract() == 0.0
 }
@@ -47,6 +49,7 @@ fn format_inf(case: Case) -> String {
     inf.to_string()
 }
 
+#[must_use]
 pub const fn decimal_point_or_empty(precision: usize, alternate_form: bool) -> &'static str {
     match (precision, alternate_form) {
         (0, true) => ".",
@@ -70,15 +73,18 @@ pub const FMT_MAX_PRECISION: usize = u16::MAX as usize;
 pub const FMT_MAX_EXP_PRECISION: usize = u16::MAX as usize - 1;
 
 #[inline]
+#[must_use]
 pub fn clamp_fmt_precision(precision: usize) -> usize {
     core::cmp::min(precision, FMT_MAX_PRECISION)
 }
 
 #[inline]
+#[must_use]
 pub fn clamp_exp_precision(precision: usize) -> usize {
     core::cmp::min(precision, FMT_MAX_EXP_PRECISION)
 }
 
+#[must_use]
 pub fn format_fixed(precision: usize, magnitude: f64, case: Case, alternate_form: bool) -> String {
     match magnitude {
         magnitude if magnitude.is_finite() => {
@@ -103,6 +109,7 @@ pub fn format_fixed(precision: usize, magnitude: f64, case: Case, alternate_form
 
 // Formats floats into Python style exponent notation, by first formatting in Rust style
 // exponent notation (`1.0000e0`), then convert to Python style (`1.0000e+00`).
+#[must_use]
 pub fn format_exponent(
     precision: usize,
     magnitude: f64,
@@ -166,6 +173,7 @@ fn remove_trailing_decimal_point(s: String) -> String {
     s
 }
 
+#[must_use]
 pub fn format_general(
     precision: usize,
     magnitude: f64,
@@ -176,7 +184,7 @@ pub fn format_general(
     match magnitude {
         magnitude if magnitude.is_finite() => {
             let exp_precision = clamp_exp_precision(precision.saturating_sub(1));
-            let r_exp = format!("{:.*e}", exp_precision, magnitude);
+            let r_exp = format!("{magnitude:.exp_precision$e}");
             let mut parts = r_exp.splitn(2, 'e');
             let base = parts.next().unwrap();
             let exponent = parts.next().unwrap().parse::<i64>().unwrap();
@@ -230,7 +238,7 @@ pub(crate) fn prefer_cpython_tie_repr(s: String, value: f64) -> String {
 
     let mut candidate = s.clone();
     candidate.replace_range(
-        digit_pos..digit_pos + 1,
+        digit_pos..=digit_pos,
         core::str::from_utf8(&[decremented]).unwrap(),
     );
     if parse_str(&candidate).is_none_or(|parsed| parsed.to_bits() != value.to_bits()) {
@@ -266,9 +274,7 @@ fn parse_decimal_rational(s: &str) -> Option<(u128, u32)> {
     };
     let significand = mantissa.strip_prefix('-').unwrap_or(mantissa);
     let dot_pos = significand.find('.');
-    let frac_digits = dot_pos
-        .map(|pos| significand.len().saturating_sub(pos + 1))
-        .unwrap_or(0);
+    let frac_digits = dot_pos.map_or(0, |pos| significand.len().saturating_sub(pos + 1));
     let mut digits = String::with_capacity(significand.len());
     for ch in significand.chars() {
         if ch != '.' {
@@ -317,6 +323,7 @@ fn decimal_distance_to_f64(s: &str, value: f64) -> Option<u128> {
 }
 
 // TODO: rewrite using format_general
+#[must_use]
 pub fn to_string(value: f64) -> String {
     let lit = format!("{value:e}");
     if let Some(position) = lit.find('e') {
@@ -339,37 +346,7 @@ pub fn to_string(value: f64) -> String {
     }
 }
 
-#[cfg(test)]
-mod tests {
-    use super::to_string;
-
-    #[test]
-    fn repr_uses_cpython_tie_digit_for_power_of_two() {
-        assert_eq!(to_string(2.0f64.powi(-25)), "2.9802322387695312e-08");
-        assert_eq!(to_string((-2.0f64).powi(-25)), "-2.9802322387695312e-08");
-        assert_eq!(to_string(2.0f64.powi(-26)), "1.4901161193847656e-08");
-        assert_eq!(
-            to_string(2.0f64.powi(-14) - 2.0f64.powi(-25)),
-            "6.1005353927612305e-05"
-        );
-    }
-
-    #[test]
-    fn repr_normal_range_uses_cpython_tie_digit() {
-        // Rust's shortest formatter yields "161852602146008.13" for this
-        // value; round-half-to-even (what `repr` uses) picks "…08.12".
-        assert_eq!(
-            to_string(f64::from_bits(0x42e26687db6b9b04)),
-            "161852602146008.12"
-        );
-        // Non-tie values are left untouched.
-        assert_eq!(to_string(1.5), "1.5");
-        assert_eq!(to_string(0.1), "0.1");
-        assert_eq!(to_string(12.34), "12.34");
-        assert_eq!(to_string(100.0), "100.0");
-    }
-}
-
+#[must_use]
 pub fn from_hex(s: &str) -> Option<f64> {
     if let Ok(f) = hexf_parse::parse_hexf64(s, false) {
         return Some(f);
@@ -418,6 +395,7 @@ pub fn from_hex(s: &str) -> Option<f64> {
     }
 }
 
+#[must_use]
 pub fn to_hex(value: f64) -> String {
     let bits = value.to_bits();
     let sign_fmt = if bits >> 63 != 0 { "-" } else { "" };
@@ -440,55 +418,86 @@ pub fn to_hex(value: f64) -> String {
     }
 }
 
-#[test]
-fn test_to_hex() {
-    use rand::RngExt;
-    assert_eq!(to_hex(f64::from_bits(1)), "0x0.0000000000001p-1022");
-    assert_eq!(to_hex(f64::from_bits(2)), "0x0.0000000000002p-1022");
-    assert_eq!(to_hex(-f64::from_bits(1)), "-0x0.0000000000001p-1022");
-    assert_eq!(to_hex(f64::MIN_POSITIVE), "0x1.0000000000000p-1022");
-    for _ in 0..20000 {
-        let bytes = rand::rng().random::<u64>();
-        let f = f64::from_bits(bytes);
-        if !f.is_finite() {
-            continue;
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn repr_uses_cpython_tie_digit_for_power_of_two() {
+        assert_eq!(to_string(2.0f64.powi(-25)), "2.9802322387695312e-08");
+        assert_eq!(to_string((-2.0f64).powi(-25)), "-2.9802322387695312e-08");
+        assert_eq!(to_string(2.0f64.powi(-26)), "1.4901161193847656e-08");
+        assert_eq!(
+            to_string(2.0f64.powi(-14) - 2.0f64.powi(-25)),
+            "6.1005353927612305e-05"
+        );
+    }
+
+    #[test]
+    fn repr_normal_range_uses_cpython_tie_digit() {
+        // Rust's shortest formatter yields "161852602146008.13" for this
+        // value; round-half-to-even (what `repr` uses) picks "…08.12".
+        assert_eq!(
+            to_string(f64::from_bits(0x42e26687db6b9b04)),
+            "161852602146008.12"
+        );
+        // Non-tie values are left untouched.
+        assert_eq!(to_string(1.5), "1.5");
+        assert_eq!(to_string(0.1), "0.1");
+        assert_eq!(to_string(12.34), "12.34");
+        assert_eq!(to_string(100.0), "100.0");
+    }
+
+    #[test]
+    fn to_hex_works() {
+        use rand::RngExt;
+        assert_eq!(to_hex(f64::from_bits(1)), "0x0.0000000000001p-1022");
+        assert_eq!(to_hex(f64::from_bits(2)), "0x0.0000000000002p-1022");
+        assert_eq!(to_hex(-f64::from_bits(1)), "-0x0.0000000000001p-1022");
+        assert_eq!(to_hex(f64::MIN_POSITIVE), "0x1.0000000000000p-1022");
+        for _ in 0..20000 {
+            let bytes = rand::rng().random::<u64>();
+            let f = f64::from_bits(bytes);
+            if !f.is_finite() {
+                continue;
+            }
+            let hex = to_hex(f);
+            // println!("{} -> {}", f, hex);
+            let roundtrip = hexf_parse::parse_hexf64(&hex, false).unwrap();
+            // println!("  -> {}", roundtrip);
+            assert!(f == roundtrip, "{f} {hex} {roundtrip}");
         }
-        let hex = to_hex(f);
-        // println!("{} -> {}", f, hex);
-        let roundtrip = hexf_parse::parse_hexf64(&hex, false).unwrap();
-        // println!("  -> {}", roundtrip);
-        assert!(f == roundtrip, "{f} {hex} {roundtrip}");
+    }
+
+    #[test]
+    fn remove_trailing_zeros_works() {
+        assert!(remove_trailing_zeros(String::from("100")) == *"1");
+        assert!(remove_trailing_zeros(String::from("100.00")) == *"100.");
+
+        // leave leading zeros untouched
+        assert!(remove_trailing_zeros(String::from("001")) == *"001");
+
+        // leave strings untouched if they don't end with 0
+        assert!(remove_trailing_zeros(String::from("101")) == *"101");
+    }
+
+    #[test]
+    fn remove_trailing_decimal_point_works() {
+        assert!(remove_trailing_decimal_point(String::from("100.")) == *"100");
+        assert!(remove_trailing_decimal_point(String::from("1.")) == *"1");
+
+        // leave leading decimal points untouched
+        assert!(remove_trailing_decimal_point(String::from(".5")) == *".5");
+    }
+
+    #[test]
+    fn maybe_remove_trailing_redundant_chars_works() {
+        assert!(maybe_remove_trailing_redundant_chars(String::from("100."), true) == *"100.");
+        assert!(maybe_remove_trailing_redundant_chars(String::from("100."), false) == *"100");
+        assert!(maybe_remove_trailing_redundant_chars(String::from("1."), false) == *"1");
+        assert!(maybe_remove_trailing_redundant_chars(String::from("10.0"), false) == *"10");
+
+        // don't truncate integers
+        assert!(maybe_remove_trailing_redundant_chars(String::from("1000"), false) == *"1000");
     }
 }
-
-#[test]
-fn test_remove_trailing_zeros() {
-    assert!(remove_trailing_zeros(String::from("100")) == *"1");
-    assert!(remove_trailing_zeros(String::from("100.00")) == *"100.");
-
-    // leave leading zeros untouched
-    assert!(remove_trailing_zeros(String::from("001")) == *"001");
-
-    // leave strings untouched if they don't end with 0
-    assert!(remove_trailing_zeros(String::from("101")) == *"101");
-}
-
-#[test]
-fn test_remove_trailing_decimal_point() {
-    assert!(remove_trailing_decimal_point(String::from("100.")) == *"100");
-    assert!(remove_trailing_decimal_point(String::from("1.")) == *"1");
-
-    // leave leading decimal points untouched
-    assert!(remove_trailing_decimal_point(String::from(".5")) == *".5");
-}
-
-#[test]
-fn test_maybe_remove_trailing_redundant_chars() {
-    assert!(maybe_remove_trailing_redundant_chars(String::from("100."), true) == *"100.");
-    assert!(maybe_remove_trailing_redundant_chars(String::from("100."), false) == *"100");
-    assert!(maybe_remove_trailing_redundant_chars(String::from("1."), false) == *"1");
-    assert!(maybe_remove_trailing_redundant_chars(String::from("10.0"), false) == *"10");
-
-    // don't truncate integers
-    assert!(maybe_remove_trailing_redundant_chars(String::from("1000"), false) == *"1000");
-}
diff --git a/crates/stdlib/src/_sqlite3.rs b/crates/stdlib/src/_sqlite3.rs
index c6fe0516a..7f3fc1606 100644
--- a/crates/stdlib/src/_sqlite3.rs
+++ b/crates/stdlib/src/_sqlite3.rs
@@ -2179,7 +2179,7 @@ mod _sqlite3 {
                         .flat_map(|x| x.to_uppercase())
                         .collect::<String>();
                     if let Some(converter) = converters().get_item_opt(&col_name, vm)? {
-                        cast_map.push(Some(converter.clone()));
+                        cast_map.push(Some(converter));
                         continue;
                     }
                 }
@@ -2189,7 +2189,7 @@ mod _sqlite3 {
                     if let Some(decltype) = decltype.split_terminator(&[' ', '(']).next() {
                         let decltype = decltype.to_uppercase();
                         if let Some(converter) = converters().get_item_opt(&decltype, vm)? {
-                            cast_map.push(Some(converter.clone()));
+                            cast_map.push(Some(converter));
                             continue;
                         }
                     }
diff --git a/crates/stdlib/src/hashlib.rs b/crates/stdlib/src/hashlib.rs
index 591604b7b..c111abaa2 100644
--- a/crates/stdlib/src/hashlib.rs
+++ b/crates/stdlib/src/hashlib.rs
@@ -262,7 +262,6 @@ pub(crate) mod _hashlib {
     }
 
     #[repr(C, align(16))]
-    #[repr(align(16))]
     struct RawHashState {
         words: [MaybeUninit<usize>; backend::HASH_STATE_STORAGE_WORDS],
     }
@@ -369,7 +368,6 @@ pub(crate) mod _hashlib {
     }
 
     #[repr(C, align(16))]
-    #[repr(align(16))]
     struct RawHmacState {
         words: [MaybeUninit<usize>; backend::HMAC_STATE_STORAGE_WORDS],
     }
diff --git a/crates/vm/src/exceptions.rs b/crates/vm/src/exceptions.rs
index 2db1bc7ec..4195b366d 100644
--- a/crates/vm/src/exceptions.rs
+++ b/crates/vm/src/exceptions.rs
@@ -838,7 +838,7 @@ impl PyRef<PyBaseException> {
                 if key_str.as_bytes().starts_with(b"__") {
                     continue;
                 }
-                self.as_object().set_attr(&key_str, value.clone(), vm)?;
+                self.as_object().set_attr(&key_str, value, vm)?;
             }
         }
         Ok(vm.ctx.none())
diff --git a/crates/vm/src/gc_state.rs b/crates/vm/src/gc_state.rs
index d7677f5fe..30fa1032c 100644
--- a/crates/vm/src/gc_state.rs
+++ b/crates/vm/src/gc_state.rs
@@ -681,8 +681,8 @@ impl GcState {
             // Reset counts for generations whose objects were promoted away.
             // For gen2 (oldest), survivors stay in-place so don't reset gen2 count.
             let reset_end = if generation >= 2 { 2 } else { generation + 1 };
-            for i in 0..reset_end {
-                self.counts[i].store(0, Ordering::Relaxed);
+            for count in self.counts.iter().take(reset_end) {
+                count.store(0, Ordering::Relaxed);
             }
 
             let duration = elapsed_secs(start_time);
@@ -857,8 +857,8 @@ impl GcState {
             drop(gen_locks);
             self.promote_survivors(generation, &survivor_refs);
             let reset_end = if generation >= 2 { 2 } else { generation + 1 };
-            for i in 0..reset_end {
-                self.counts[i].store(0, Ordering::Relaxed);
+            for count in self.counts.iter().take(reset_end) {
+                count.store(0, Ordering::Relaxed);
             }
 
             let duration = elapsed_secs(start_time);
@@ -880,8 +880,8 @@ impl GcState {
         if unreachable_refs.is_empty() {
             self.promote_survivors(generation, &survivor_refs);
             let reset_end = if generation >= 2 { 2 } else { generation + 1 };
-            for i in 0..reset_end {
-                self.counts[i].store(0, Ordering::Relaxed);
+            for count in self.counts.iter().take(reset_end) {
+                count.store(0, Ordering::Relaxed);
             }
 
             let duration = elapsed_secs(start_time);
@@ -1107,8 +1107,8 @@ impl GcState {
         // Reset counts for generations whose objects were promoted away.
         // For gen2 (oldest), survivors stay in-place so don't reset gen2 count.
         let reset_end = if generation >= 2 { 2 } else { generation + 1 };
-        for i in 0..reset_end {
-            self.counts[i].store(0, Ordering::Relaxed);
+        for count in self.counts.iter().take(reset_end) {
+            count.store(0, Ordering::Relaxed);
         }
 
         let duration = elapsed_secs(start_time);
diff --git a/crates/vm/src/stdlib/_ctypes/structure.rs b/crates/vm/src/stdlib/_ctypes/structure.rs
index 39ab31a27..474d9eaca 100644
--- a/crates/vm/src/stdlib/_ctypes/structure.rs
+++ b/crates/vm/src/stdlib/_ctypes/structure.rs
@@ -417,7 +417,6 @@ impl PyCStructType {
 
             // Create CField descriptor with padding-adjusted offset
             let field_type_ref = field_type
-                .clone()
                 .downcast::<PyType>()
                 .map_err(|_| vm.new_type_error("_fields_ type must be a ctypes type"))?;
 
diff --git a/crates/vm/src/stdlib/_ctypes/union.rs b/crates/vm/src/stdlib/_ctypes/union.rs
index 2acf70144..e03200041 100644
--- a/crates/vm/src/stdlib/_ctypes/union.rs
+++ b/crates/vm/src/stdlib/_ctypes/union.rs
@@ -274,7 +274,6 @@ impl PyCUnionType {
 
             // For Union, all fields start at offset 0
             let field_type_ref = field_type
-                .clone()
                 .downcast::<PyType>()
                 .map_err(|_| vm.new_type_error("_fields_ type must be a ctypes type"))?;
 
diff --git a/crates/vm/src/stdlib/_io.rs b/crates/vm/src/stdlib/_io.rs
index e90cac5ea..3bec5b299 100644
--- a/crates/vm/src/stdlib/_io.rs
+++ b/crates/vm/src/stdlib/_io.rs
@@ -537,7 +537,7 @@ mod _io {
             for line in it.iter(vm)? {
                 let line = line?;
                 let line_len = line.length(vm)?;
-                ret.push(line.clone());
+                ret.push(line);
                 full_len += line_len;
                 if full_len > hint {
                     break;
diff --git a/crates/vm/src/stdlib/gc.rs b/crates/vm/src/stdlib/gc.rs
index a73d2adfa..42b74eb33 100644
--- a/crates/vm/src/stdlib/gc.rs
+++ b/crates/vm/src/stdlib/gc.rs
@@ -238,7 +238,7 @@ mod gc {
                 continue;
             }
             if refers_to_target(obj.as_ref()) {
-                result.push(obj.clone());
+                result.push(obj);
             }
         }
 
diff --git a/crates/vm/src/stdlib/sys/monitoring.rs b/crates/vm/src/stdlib/sys/monitoring.rs
index 28374ea7d..87fb6cb7e 100644
--- a/crates/vm/src/stdlib/sys/monitoring.rs
+++ b/crates/vm/src/stdlib/sys/monitoring.rs
@@ -324,28 +324,33 @@ pub(crate) fn instrument_code(code: &Py<PyCode>, events: u32) {
 
     // Phase 1: Remove INSTRUMENTED_LINE → restore from side-table
     if let Some(data) = monitoring_data.as_mut() {
-        for i in 0..len {
-            if data.line_opcodes[i] != 0 {
-                let original = Instruction::try_from(data.line_opcodes[i])
-                    .expect("invalid opcode in line side-table");
+        for (i, opcode) in data.line_opcodes.iter_mut().enumerate().take(len) {
+            if *opcode != 0 {
+                let original =
+                    Instruction::try_from(*opcode).expect("invalid opcode in line side-table");
                 unsafe {
                     code.code.instructions.replace_op(i, original);
                 }
-                data.line_opcodes[i] = 0;
+                *opcode = 0;
             }
         }
     }
 
     // Phase 2: Remove INSTRUMENTED_INSTRUCTION → restore from side-table
     if let Some(data) = monitoring_data.as_mut() {
-        for i in 0..len {
-            if data.per_instruction_opcodes[i] != 0 {
-                let original = Instruction::try_from(data.per_instruction_opcodes[i])
+        for (i, opcode) in data
+            .per_instruction_opcodes
+            .iter_mut()
+            .enumerate()
+            .take(len)
+        {
+            if *opcode != 0 {
+                let original = Instruction::try_from(*opcode)
                     .expect("invalid opcode in instruction side-table");
                 unsafe {
                     code.code.instructions.replace_op(i, original);
                 }
-                data.per_instruction_opcodes[i] = 0;
+                *opcode = 0;
             }
         }
     }
@@ -812,9 +817,9 @@ fn all_events(vm: &VirtualMachine) -> PyResult<PyDictRef> {
             .filter_map(|(event_id, event_name)| {
                 let event_bit = 1u32 << event_id;
                 let mut tools_mask = 0u8;
-                for tool in 0..TOOL_LIMIT {
-                    if (state.global_events[tool] & event_bit) != 0 {
-                        tools_mask |= 1 << tool;
+                for (i, tool) in state.global_events.iter().enumerate().take(TOOL_LIMIT) {
+                    if (tool & event_bit) != 0 {
+                        tools_mask |= 1 << i;
                     }
                 }
                 if tools_mask != 0 {
diff --git a/crates/wtf8/Cargo.toml b/crates/wtf8/Cargo.toml
index 20bf82489..0afc826f5 100644
--- a/crates/wtf8/Cargo.toml
+++ b/crates/wtf8/Cargo.toml
@@ -8,6 +8,9 @@ rust-version.workspace = true
 repository.workspace = true
 license.workspace = true
 
+[lints]
+workspace = true
+
 [dependencies]
 ascii = { workspace = true, features = ["alloc"] }
 bstr = { workspace = true, features = ["alloc"] }
diff --git a/crates/wtf8/src/concat.rs b/crates/wtf8/src/concat.rs
index 055a401d6..200dabfde 100644
--- a/crates/wtf8/src/concat.rs
+++ b/crates/wtf8/src/concat.rs
@@ -67,7 +67,7 @@ impl Wtf8Concat for CodePoint {
 /// display output will be replaced with U+FFFD. Use direct [`Wtf8Concat`]
 /// impls for surrogate-preserving concatenation.
 #[allow(dead_code)]
-pub struct DisplayAsWtf8<T>(pub T);
+pub(crate) struct DisplayAsWtf8<T>(pub T);
 
 impl<T: fmt::Display> Wtf8Concat for DisplayAsWtf8<T> {
     #[inline]
@@ -112,9 +112,9 @@ impl<T: Wtf8Concat + ?Sized> Wtf8Concat for Box<T> {
     }
 }
 
-impl<T: Wtf8Concat + ?Sized> Wtf8Concat for Cow<'_, T>
+impl<T> Wtf8Concat for Cow<'_, T>
 where
-    T: ToOwned,
+    T: ToOwned + Wtf8Concat + ?Sized,
 {
     #[inline]
     fn fmt_wtf8(&self, buf: &mut Wtf8Buf) {
diff --git a/crates/wtf8/src/core_char.rs b/crates/wtf8/src/core_char.rs
index 66f321d8a..69a0f1934 100644
--- a/crates/wtf8/src/core_char.rs
+++ b/crates/wtf8/src/core_char.rs
@@ -3,8 +3,8 @@
 
 use core::slice;
 
-pub const MAX_LEN_UTF8: usize = 4;
-pub const MAX_LEN_UTF16: usize = 2;
+pub(crate) const MAX_LEN_UTF8: usize = 4;
+pub(crate) const MAX_LEN_UTF16: usize = 2;
 
 // UTF-8 ranges and tags for encoding characters
 const TAG_CONT: u8 = 0b1000_0000;
@@ -17,7 +17,7 @@ const MAX_THREE_B: u32 = 0x10000;
 
 #[inline]
 #[must_use]
-pub const fn len_utf8(code: u32) -> usize {
+pub(crate) const fn len_utf8(code: u32) -> usize {
     match code {
         ..MAX_ONE_B => 1,
         ..MAX_TWO_B => 2,
@@ -47,7 +47,7 @@ const fn len_utf16(code: u32) -> usize {
 /// A buffer of length four is large enough to encode any `char`.
 #[doc(hidden)]
 #[inline]
-pub fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> &mut [u8] {
+pub(crate) fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> &mut [u8] {
     let len = len_utf8(code);
     match (len, &mut *dst) {
         (1, [a, ..]) => {
@@ -91,7 +91,7 @@ pub fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> &mut [u8] {
 /// A buffer of length 2 is large enough to encode any `char`.
 #[doc(hidden)]
 #[inline]
-pub fn encode_utf16_raw(mut code: u32, dst: &mut [u16]) -> &mut [u16] {
+pub(crate) fn encode_utf16_raw(mut code: u32, dst: &mut [u16]) -> &mut [u16] {
     let len = len_utf16(code);
     match (len, &mut *dst) {
         (1, [a, ..]) => {
diff --git a/crates/wtf8/src/core_str.rs b/crates/wtf8/src/core_str.rs
index 56f715cf7..18c9472c7 100644
--- a/crates/wtf8/src/core_str.rs
+++ b/crates/wtf8/src/core_str.rs
@@ -30,7 +30,7 @@ pub(super) const fn utf8_is_cont_byte(byte: u8) -> bool {
 ///
 /// `bytes` must produce a valid UTF-8-like (UTF-8 or WTF-8) string
 #[inline]
-pub unsafe fn next_code_point<'a, I: Iterator<Item = &'a u8>>(bytes: &mut I) -> Option<u32> {
+pub(crate) unsafe fn next_code_point<'a, I: Iterator<Item = &'a u8>>(bytes: &mut I) -> Option<u32> {
     // Decode UTF-8
     let x = *bytes.next()?;
     if x < 128 {
@@ -73,7 +73,7 @@ pub unsafe fn next_code_point<'a, I: Iterator<Item = &'a u8>>(bytes: &mut I) ->
 ///
 /// `bytes` must produce a valid UTF-8-like (UTF-8 or WTF-8) string
 #[inline]
-pub unsafe fn next_code_point_reverse<'a, I>(bytes: &mut I) -> Option<u32>
+pub(crate) unsafe fn next_code_point_reverse<'a, I>(bytes: &mut I) -> Option<u32>
 where
     I: DoubleEndedIterator<Item = &'a u8>,
 {
diff --git a/crates/wtf8/src/lib.rs b/crates/wtf8/src/lib.rs
index 7625e6f18..69c8586dd 100644
--- a/crates/wtf8/src/lib.rs
+++ b/crates/wtf8/src/lib.rs
@@ -96,17 +96,19 @@ impl CodePoint {
     ///
     /// `value` must be less than or equal to 0x10FFFF.
     #[inline]
-    pub const unsafe fn from_u32_unchecked(value: u32) -> CodePoint {
-        CodePoint { value }
+    #[must_use]
+    pub const unsafe fn from_u32_unchecked(value: u32) -> Self {
+        Self { value }
     }
 
     /// Creates a new `CodePoint` if the value is a valid code point.
     ///
     /// Returns `None` if `value` is above 0x10FFFF.
     #[inline]
-    pub const fn from_u32(value: u32) -> Option<CodePoint> {
+    #[must_use]
+    pub const fn from_u32(value: u32) -> Option<Self> {
         match value {
-            0..=0x10FFFF => Some(CodePoint { value }),
+            0..=0x10FFFF => Some(Self { value }),
             _ => None,
         }
     }
@@ -115,20 +117,23 @@ impl CodePoint {
     ///
     /// Since all Unicode scalar values are code points, this always succeeds.
     #[inline]
-    pub const fn from_char(value: char) -> CodePoint {
-        CodePoint {
+    #[must_use]
+    pub const fn from_char(value: char) -> Self {
+        Self {
             value: value as u32,
         }
     }
 
     /// Returns the numeric value of the code point.
     #[inline]
+    #[must_use]
     pub const fn to_u32(self) -> u32 {
         self.value
     }
 
     /// Returns the numeric value of the code point if it is a leading surrogate.
     #[inline]
+    #[must_use]
     pub const fn to_lead_surrogate(self) -> Option<LeadSurrogate> {
         match self.value {
             lead @ 0xD800..=0xDBFF => Some(LeadSurrogate(lead as u16)),
@@ -138,6 +143,7 @@ impl CodePoint {
 
     /// Returns the numeric value of the code point if it is a trailing surrogate.
     #[inline]
+    #[must_use]
     pub const fn to_trail_surrogate(self) -> Option<TrailSurrogate> {
         match self.value {
             trail @ 0xDC00..=0xDFFF => Some(TrailSurrogate(trail as u16)),
@@ -149,6 +155,7 @@ impl CodePoint {
     ///
     /// Returns `None` if the code point is a surrogate (from U+D800 to U+DFFF).
     #[inline]
+    #[must_use]
     pub const fn to_char(self) -> Option<char> {
         match self.value {
             0xD800..=0xDFFF => None,
@@ -161,6 +168,7 @@ impl CodePoint {
     /// Returns `'\u{FFFD}'` (the replacement character “�”)
     /// if the code point is a surrogate (from U+D800 to U+DFFF).
     #[inline]
+    #[must_use]
     pub fn to_char_lossy(self) -> char {
         self.to_char().unwrap_or('\u{FFFD}')
     }
@@ -173,10 +181,12 @@ impl CodePoint {
         unsafe { Wtf8::from_mut_bytes_unchecked(encode_utf8_raw(self.value, dst)) }
     }
 
+    #[must_use]
     pub const fn len_wtf8(&self) -> usize {
         len_utf8(self.value)
     }
 
+    #[must_use]
     pub fn is_ascii(&self) -> bool {
         self.is_char_and(|c| c.is_ascii())
     }
@@ -230,6 +240,7 @@ pub struct LeadSurrogate(u16);
 pub struct TrailSurrogate(u16);
 
 impl LeadSurrogate {
+    #[must_use]
     pub const fn merge(self, trail: TrailSurrogate) -> char {
         decode_surrogate_pair(self.0, trail.0)
     }
@@ -288,14 +299,16 @@ impl fmt::Display for Wtf8Buf {
 impl Wtf8Buf {
     /// Creates a new, empty WTF-8 string.
     #[inline]
-    pub fn new() -> Wtf8Buf {
-        Wtf8Buf::default()
+    #[must_use]
+    pub fn new() -> Self {
+        Self::default()
     }
 
     /// Creates a new, empty WTF-8 string with pre-allocated capacity for `capacity` bytes.
     #[inline]
-    pub fn with_capacity(capacity: usize) -> Wtf8Buf {
-        Wtf8Buf {
+    #[must_use]
+    pub fn with_capacity(capacity: usize) -> Self {
+        Self {
             bytes: Vec::with_capacity(capacity),
         }
     }
@@ -306,8 +319,9 @@ impl Wtf8Buf {
     ///
     /// `value` must contain valid WTF-8.
     #[inline]
-    pub const unsafe fn from_bytes_unchecked(value: Vec<u8>) -> Wtf8Buf {
-        Wtf8Buf { bytes: value }
+    #[must_use]
+    pub const unsafe fn from_bytes_unchecked(value: Vec<u8>) -> Self {
+        Self { bytes: value }
     }
 
     /// Create a WTF-8 string from a WTF-8 byte vec.
@@ -324,13 +338,14 @@ impl Wtf8Buf {
     ///
     /// Since WTF-8 is a superset of UTF-8, this always succeeds.
     #[inline]
-    pub fn from_string(string: String) -> Wtf8Buf {
-        Wtf8Buf {
+    #[must_use]
+    pub fn from_string(string: String) -> Self {
+        Self {
             bytes: string.into_bytes(),
         }
     }
 
-    pub fn join<I, S>(sep: impl AsRef<Wtf8>, iter: I) -> Wtf8Buf
+    pub fn join<I, S>(sep: impl AsRef<Wtf8>, iter: I) -> Self
     where
         I: IntoIterator<Item = S>,
         S: AsRef<Wtf8>,
@@ -339,7 +354,7 @@ impl Wtf8Buf {
         let mut iter = iter.into_iter();
         let mut buf = match iter.next() {
             Some(first) => first.as_ref().to_owned(),
-            None => return Wtf8Buf::new(),
+            None => return Self::new(),
         };
         for part in iter {
             buf.push_wtf8(sep);
@@ -356,9 +371,10 @@ impl Wtf8Buf {
     ///
     /// This is lossless: calling `.encode_wide()` on the resulting string
     /// will always return the original code units.
-    pub fn from_wide(v: &[u16]) -> Wtf8Buf {
-        let mut string = Wtf8Buf::with_capacity(v.len());
-        for item in char::decode_utf16(v.iter().cloned()) {
+    #[must_use]
+    pub fn from_wide(v: &[u16]) -> Self {
+        let mut string = Self::with_capacity(v.len());
+        for item in char::decode_utf16(v.iter().copied()) {
             match item {
                 Ok(ch) => string.push_char(ch),
                 Err(surrogate) => {
@@ -375,6 +391,7 @@ impl Wtf8Buf {
     }
 
     #[inline]
+    #[must_use]
     pub fn as_slice(&self) -> &Wtf8 {
         unsafe { Wtf8::from_bytes_unchecked(&self.bytes) }
     }
@@ -452,12 +469,14 @@ impl Wtf8Buf {
     }
 
     #[inline]
+    #[must_use]
     pub fn leak<'a>(self) -> &'a mut Wtf8 {
         unsafe { Wtf8::from_mut_bytes_unchecked(self.bytes.leak()) }
     }
 
     /// Returns the number of bytes that this string buffer can hold without reallocating.
     #[inline]
+    #[must_use]
     pub const fn capacity(&self) -> usize {
         self.bytes.capacity()
     }
@@ -521,6 +540,7 @@ impl Wtf8Buf {
 
     /// Consumes the WTF-8 string and tries to convert it to a vec of bytes.
     #[inline]
+    #[must_use]
     pub fn into_bytes(self) -> Vec<u8> {
         self.bytes
     }
@@ -532,7 +552,7 @@ impl Wtf8Buf {
     /// If the contents are not well-formed UTF-8
     /// (that is, if the string contains surrogates),
     /// the original WTF-8 string is returned instead.
-    pub fn into_string(self) -> Result<String, Wtf8Buf> {
+    pub fn into_string(self) -> Result<String, Self> {
         if self.is_utf8() {
             Ok(unsafe { String::from_utf8_unchecked(self.bytes) })
         } else {
@@ -545,6 +565,7 @@ impl Wtf8Buf {
     /// This does not copy the data (but may overwrite parts of it in place).
     ///
     /// Surrogates are replaced with `"\u{FFFD}"` (the replacement character “�”)
+    #[must_use]
     pub fn into_string_lossy(mut self) -> String {
         let mut pos = 0;
         while let Some((surrogate_pos, _)) = self.next_surrogate(pos) {
@@ -558,15 +579,17 @@ impl Wtf8Buf {
 
     /// Converts this `Wtf8Buf` into a boxed `Wtf8`.
     #[inline]
+    #[must_use]
     pub fn into_box(self) -> Box<Wtf8> {
         // SAFETY: relies on `Wtf8` being `repr(transparent)`.
         unsafe { mem::transmute(self.bytes.into_boxed_slice()) }
     }
 
     /// Converts a `Box<Wtf8>` into a `Wtf8Buf`.
-    pub fn from_box(boxed: Box<Wtf8>) -> Wtf8Buf {
+    #[must_use]
+    pub fn from_box(boxed: Box<Wtf8>) -> Self {
         let bytes: Box<[u8]> = unsafe { mem::transmute(boxed) };
-        Wtf8Buf {
+        Self {
             bytes: bytes.into_vec(),
         }
     }
@@ -577,8 +600,8 @@ impl Wtf8Buf {
 /// This replaces surrogate code point pairs with supplementary code points,
 /// like concatenating ill-formed UTF-16 strings effectively would.
 impl FromIterator<CodePoint> for Wtf8Buf {
-    fn from_iter<T: IntoIterator<Item = CodePoint>>(iter: T) -> Wtf8Buf {
-        let mut string = Wtf8Buf::new();
+    fn from_iter<T: IntoIterator<Item = CodePoint>>(iter: T) -> Self {
+        let mut string = Self::new();
         string.extend(iter);
         string
     }
@@ -613,7 +636,7 @@ impl<W: AsRef<Wtf8>> Extend<W> for Wtf8Buf {
 
 impl<W: AsRef<Wtf8>> FromIterator<W> for Wtf8Buf {
     fn from_iter<T: IntoIterator<Item = W>>(iter: T) -> Self {
-        let mut buf = Wtf8Buf::new();
+        let mut buf = Self::new();
         iter.into_iter().for_each(|w| buf.push_wtf8(w.as_ref()));
         buf
     }
@@ -633,19 +656,19 @@ impl AsRef<Wtf8> for Wtf8Buf {
 
 impl From<String> for Wtf8Buf {
     fn from(s: String) -> Self {
-        Wtf8Buf::from_string(s)
+        Self::from_string(s)
     }
 }
 
 impl From<&str> for Wtf8Buf {
     fn from(s: &str) -> Self {
-        Wtf8Buf::from_string(s.to_owned())
+        Self::from_string(s.to_owned())
     }
 }
 
 impl From<ascii::AsciiString> for Wtf8Buf {
     fn from(s: ascii::AsciiString) -> Self {
-        Wtf8Buf::from_string(s.into())
+        Self::from_string(s.into())
     }
 }
 
@@ -658,8 +681,8 @@ pub struct Wtf8 {
     bytes: [u8],
 }
 
-impl AsRef<Wtf8> for Wtf8 {
-    fn as_ref(&self) -> &Wtf8 {
+impl AsRef<Self> for Wtf8 {
+    fn as_ref(&self) -> &Self {
         self
     }
 }
@@ -730,9 +753,8 @@ impl fmt::Display for Wtf8 {
                     let s = unsafe { str::from_utf8_unchecked(&wtf8_bytes[pos..]) };
                     if pos == 0 {
                         return s.fmt(formatter);
-                    } else {
-                        return formatter.write_str(s);
                     }
+                    return formatter.write_str(s);
                 }
             }
         }
@@ -757,7 +779,7 @@ impl Wtf8 {
     ///
     /// Since WTF-8 is a superset of UTF-8, this always succeeds.
     #[inline]
-    pub fn new<S: AsRef<Wtf8> + ?Sized>(value: &S) -> &Wtf8 {
+    pub fn new<S: AsRef<Self> + ?Sized>(value: &S) -> &Self {
         value.as_ref()
     }
 
@@ -767,9 +789,10 @@ impl Wtf8 {
     ///
     /// `value` must contain valid WTF-8.
     #[inline]
-    pub const unsafe fn from_bytes_unchecked(value: &[u8]) -> &Wtf8 {
+    #[must_use]
+    pub const unsafe fn from_bytes_unchecked(value: &[u8]) -> &Self {
         // SAFETY: start with &[u8], end with fancy &[u8]
-        unsafe { &*(value as *const [u8] as *const Wtf8) }
+        unsafe { &*(value as *const [u8] as *const Self) }
     }
 
     /// Creates a mutable WTF-8 slice from a mutable WTF-8 byte slice.
@@ -777,15 +800,16 @@ impl Wtf8 {
     /// Since the byte slice is not checked for valid WTF-8, this functions is
     /// marked unsafe.
     #[inline]
-    const unsafe fn from_mut_bytes_unchecked(value: &mut [u8]) -> &mut Wtf8 {
+    const unsafe fn from_mut_bytes_unchecked(value: &mut [u8]) -> &mut Self {
         // SAFETY: start with &mut [u8], end with fancy &mut [u8]
-        unsafe { &mut *(value as *mut [u8] as *mut Wtf8) }
+        unsafe { &mut *(value as *mut [u8] as *mut Self) }
     }
 
     /// Create a WTF-8 slice from a WTF-8 byte slice.
     //
     // whoops! using WTF-8 for interchange!
     #[inline]
+    #[must_use]
     pub fn from_bytes(b: &[u8]) -> Option<&Self> {
         let mut rest = b;
         while let Err(e) = core::str::from_utf8(rest) {
@@ -793,7 +817,7 @@ impl Wtf8 {
             let _ = Self::decode_surrogate(rest)?;
             rest = &rest[3..];
         }
-        Some(unsafe { Wtf8::from_bytes_unchecked(b) })
+        Some(unsafe { Self::from_bytes_unchecked(b) })
     }
 
     fn decode_surrogate(b: &[u8]) -> Option<CodePoint> {
@@ -805,11 +829,13 @@ impl Wtf8 {
 
     /// Returns the length, in WTF-8 bytes.
     #[inline]
+    #[must_use]
     pub const fn len(&self) -> usize {
         self.bytes.len()
     }
 
     #[inline]
+    #[must_use]
     pub const fn is_empty(&self) -> bool {
         self.bytes.is_empty()
     }
@@ -821,6 +847,7 @@ impl Wtf8 {
     ///
     /// Panics if `position` is beyond the end of the string.
     #[inline]
+    #[must_use]
     pub const fn ascii_byte_at(&self, position: usize) -> u8 {
         match self.bytes[position] {
             ascii_byte @ 0x00..=0x7F => ascii_byte,
@@ -830,6 +857,7 @@ impl Wtf8 {
 
     /// Returns an iterator for the string’s code points.
     #[inline]
+    #[must_use]
     pub fn code_points(&self) -> Wtf8CodePoints<'_> {
         Wtf8CodePoints {
             bytes: self.bytes.iter(),
@@ -838,6 +866,7 @@ impl Wtf8 {
 
     /// Returns an iterator for the string’s code points and their indices.
     #[inline]
+    #[must_use]
     pub fn code_point_indices(&self) -> Wtf8CodePointIndices<'_> {
         Wtf8CodePointIndices {
             front_offset: 0,
@@ -847,6 +876,7 @@ impl Wtf8 {
 
     /// Access raw bytes of WTF-8 data
     #[inline]
+    #[must_use]
     pub const fn as_bytes(&self) -> &[u8] {
         &self.bytes
     }
@@ -862,6 +892,7 @@ impl Wtf8 {
     }
 
     /// Creates an owned `Wtf8Buf` from a borrowed `Wtf8`.
+    #[must_use]
     pub fn to_wtf8_buf(&self) -> Wtf8Buf {
         Wtf8Buf {
             bytes: self.bytes.to_vec(),
@@ -874,6 +905,7 @@ impl Wtf8 {
     /// Surrogates are replaced with `"\u{FFFD}"` (the replacement character “�”).
     ///
     /// This only copies the data if necessary (if it contains any surrogate).
+    #[must_use]
     pub fn to_string_lossy(&self) -> Cow<'_, str> {
         let Some((surrogate_pos, _)) = self.next_surrogate(0) else {
             return Cow::Borrowed(unsafe { str::from_utf8_unchecked(&self.bytes) });
@@ -905,6 +937,7 @@ impl Wtf8 {
     /// calling `Wtf8Buf::from_ill_formed_utf16` on the resulting code units
     /// would always return the original WTF-8 string.
     #[inline]
+    #[must_use]
     pub fn encode_wide(&self) -> EncodeWide<'_> {
         EncodeWide {
             code_points: self.code_points(),
@@ -912,6 +945,7 @@ impl Wtf8 {
         }
     }
 
+    #[must_use]
     pub const fn chunks(&self) -> Wtf8Chunks<'_> {
         Wtf8Chunks { wtf8: self }
     }
@@ -956,19 +990,22 @@ impl Wtf8 {
         }
     }
 
+    #[must_use]
     pub fn is_code_point_boundary(&self, index: usize) -> bool {
         is_code_point_boundary(self, index)
     }
 
     /// Boxes this `Wtf8`.
     #[inline]
-    pub fn into_box(&self) -> Box<Wtf8> {
+    #[must_use]
+    pub fn into_box(&self) -> Box<Self> {
         let boxed: Box<[u8]> = self.bytes.into();
         unsafe { mem::transmute(boxed) }
     }
 
     /// Creates a boxed, empty `Wtf8`.
-    pub fn empty_box() -> Box<Wtf8> {
+    #[must_use]
+    pub fn empty_box() -> Box<Self> {
         let boxed: Box<[u8]> = Default::default();
         unsafe { mem::transmute(boxed) }
     }
@@ -984,6 +1021,7 @@ impl Wtf8 {
     }
 
     #[inline]
+    #[must_use]
     pub fn to_ascii_lowercase(&self) -> Wtf8Buf {
         Wtf8Buf {
             bytes: self.bytes.to_ascii_lowercase(),
@@ -991,12 +1029,14 @@ impl Wtf8 {
     }
 
     #[inline]
+    #[must_use]
     pub fn to_ascii_uppercase(&self) -> Wtf8Buf {
         Wtf8Buf {
             bytes: self.bytes.to_ascii_uppercase(),
         }
     }
 
+    #[must_use]
     pub fn to_lowercase(&self) -> Wtf8Buf {
         let mut buf = Wtf8Buf::with_capacity(self.len());
         for chunk in self.chunks() {
@@ -1008,6 +1048,7 @@ impl Wtf8 {
         buf
     }
 
+    #[must_use]
     pub fn to_uppercase(&self) -> Wtf8Buf {
         let mut buf = Wtf8Buf::with_capacity(self.len());
         for chunk in self.chunks() {
@@ -1020,57 +1061,63 @@ impl Wtf8 {
     }
 
     #[inline]
+    #[must_use]
     pub const fn is_ascii(&self) -> bool {
         self.bytes.is_ascii()
     }
 
     #[inline]
+    #[must_use]
     pub fn is_utf8(&self) -> bool {
         self.next_surrogate(0).is_none()
     }
 
     #[inline]
+    #[must_use]
     pub fn eq_ignore_ascii_case(&self, other: &Self) -> bool {
         self.bytes.eq_ignore_ascii_case(&other.bytes)
     }
 
-    pub fn split(&self, pat: &Wtf8) -> impl Iterator<Item = &Self> {
+    pub fn split(&self, pat: &Self) -> impl Iterator<Item = &Self> {
         self.as_bytes()
             .split_str(pat)
-            .map(|w| unsafe { Wtf8::from_bytes_unchecked(w) })
+            .map(|w| unsafe { Self::from_bytes_unchecked(w) })
     }
 
-    pub fn splitn(&self, n: usize, pat: &Wtf8) -> impl Iterator<Item = &Self> {
+    pub fn splitn(&self, n: usize, pat: &Self) -> impl Iterator<Item = &Self> {
         self.as_bytes()
             .splitn_str(n, pat)
-            .map(|w| unsafe { Wtf8::from_bytes_unchecked(w) })
+            .map(|w| unsafe { Self::from_bytes_unchecked(w) })
     }
 
-    pub fn rsplit(&self, pat: &Wtf8) -> impl Iterator<Item = &Self> {
+    pub fn rsplit(&self, pat: &Self) -> impl Iterator<Item = &Self> {
         self.as_bytes()
             .rsplit_str(pat)
-            .map(|w| unsafe { Wtf8::from_bytes_unchecked(w) })
+            .map(|w| unsafe { Self::from_bytes_unchecked(w) })
     }
 
-    pub fn rsplitn(&self, n: usize, pat: &Wtf8) -> impl Iterator<Item = &Self> {
+    pub fn rsplitn(&self, n: usize, pat: &Self) -> impl Iterator<Item = &Self> {
         self.as_bytes()
             .rsplitn_str(n, pat)
-            .map(|w| unsafe { Wtf8::from_bytes_unchecked(w) })
+            .map(|w| unsafe { Self::from_bytes_unchecked(w) })
     }
 
+    #[must_use]
     pub fn trim(&self) -> &Self {
         let w = self.bytes.trim();
-        unsafe { Wtf8::from_bytes_unchecked(w) }
+        unsafe { Self::from_bytes_unchecked(w) }
     }
 
+    #[must_use]
     pub fn trim_start(&self) -> &Self {
         let w = self.bytes.trim_start();
-        unsafe { Wtf8::from_bytes_unchecked(w) }
+        unsafe { Self::from_bytes_unchecked(w) }
     }
 
+    #[must_use]
     pub fn trim_end(&self) -> &Self {
         let w = self.bytes.trim_end();
-        unsafe { Wtf8::from_bytes_unchecked(w) }
+        unsafe { Self::from_bytes_unchecked(w) }
     }
 
     pub fn trim_start_matches(&self, f: impl Fn(CodePoint) -> bool) -> &Self {
@@ -1109,26 +1156,30 @@ impl Wtf8 {
         self.trim_start_matches(&f).trim_end_matches(&f)
     }
 
-    pub fn find(&self, pat: &Wtf8) -> Option<usize> {
+    #[must_use]
+    pub fn find(&self, pat: &Self) -> Option<usize> {
         memchr::memmem::find(self.as_bytes(), pat.as_bytes())
     }
 
-    pub fn rfind(&self, pat: &Wtf8) -> Option<usize> {
+    #[must_use]
+    pub fn rfind(&self, pat: &Self) -> Option<usize> {
         memchr::memmem::rfind(self.as_bytes(), pat.as_bytes())
     }
 
-    pub fn find_iter(&self, pat: &Wtf8) -> impl Iterator<Item = usize> {
+    pub fn find_iter(&self, pat: &Self) -> impl Iterator<Item = usize> {
         memchr::memmem::find_iter(self.as_bytes(), pat.as_bytes())
     }
 
-    pub fn rfind_iter(&self, pat: &Wtf8) -> impl Iterator<Item = usize> {
+    pub fn rfind_iter(&self, pat: &Self) -> impl Iterator<Item = usize> {
         memchr::memmem::rfind_iter(self.as_bytes(), pat.as_bytes())
     }
 
-    pub fn contains(&self, pat: &Wtf8) -> bool {
+    #[must_use]
+    pub fn contains(&self, pat: &Self) -> bool {
         self.bytes.contains_str(pat)
     }
 
+    #[must_use]
     pub fn contains_code_point(&self, pat: CodePoint) -> bool {
         self.bytes
             .contains_str(pat.encode_wtf8(&mut [0; MAX_LEN_UTF8]))
@@ -1154,27 +1205,28 @@ impl Wtf8 {
         }
     }
 
-    pub fn ends_with(&self, w: impl AsRef<Wtf8>) -> bool {
+    pub fn ends_with(&self, w: impl AsRef<Self>) -> bool {
         self.bytes.ends_with_str(w.as_ref())
     }
 
-    pub fn starts_with(&self, w: impl AsRef<Wtf8>) -> bool {
+    pub fn starts_with(&self, w: impl AsRef<Self>) -> bool {
         self.bytes.starts_with_str(w.as_ref())
     }
 
-    pub fn strip_prefix(&self, w: impl AsRef<Wtf8>) -> Option<&Self> {
+    pub fn strip_prefix(&self, w: impl AsRef<Self>) -> Option<&Self> {
         self.bytes
             .strip_prefix(w.as_ref().as_bytes())
-            .map(|w| unsafe { Wtf8::from_bytes_unchecked(w) })
+            .map(|w| unsafe { Self::from_bytes_unchecked(w) })
     }
 
-    pub fn strip_suffix(&self, w: impl AsRef<Wtf8>) -> Option<&Self> {
+    pub fn strip_suffix(&self, w: impl AsRef<Self>) -> Option<&Self> {
         self.bytes
             .strip_suffix(w.as_ref().as_bytes())
-            .map(|w| unsafe { Wtf8::from_bytes_unchecked(w) })
+            .map(|w| unsafe { Self::from_bytes_unchecked(w) })
     }
 
-    pub fn replace(&self, from: &Wtf8, to: &Wtf8) -> Wtf8Buf {
+    #[must_use]
+    pub fn replace(&self, from: &Self, to: &Self) -> Wtf8Buf {
         if from.is_empty() {
             return self.insert_at_boundaries(to, usize::MAX);
         }
@@ -1182,7 +1234,8 @@ impl Wtf8 {
         unsafe { Wtf8Buf::from_bytes_unchecked(w) }
     }
 
-    pub fn replacen(&self, from: &Wtf8, to: &Wtf8, n: usize) -> Wtf8Buf {
+    #[must_use]
+    pub fn replacen(&self, from: &Self, to: &Self, n: usize) -> Wtf8Buf {
         if from.is_empty() {
             return self.insert_at_boundaries(to, n);
         }
@@ -1198,7 +1251,7 @@ impl Wtf8 {
     /// *byte*, so it splits a multi-byte code point down the middle and leaves
     /// bytes that are no longer WTF-8 at all. A needle that is not empty is
     /// safe there, because a WTF-8 sequence never starts inside another one.
-    fn insert_at_boundaries(&self, to: &Wtf8, limit: usize) -> Wtf8Buf {
+    fn insert_at_boundaries(&self, to: &Self, limit: usize) -> Wtf8Buf {
         let mut result = Wtf8Buf::with_capacity(self.len());
         let mut inserted = 0;
 
@@ -1237,11 +1290,11 @@ impl AsRef<[u8]> for Wtf8 {
 /// Panics when `begin` and `end` do not point to code point boundaries,
 /// or point beyond the end of the string.
 impl ops::Index<ops::Range<usize>> for Wtf8 {
-    type Output = Wtf8;
+    type Output = Self;
 
     #[inline]
     #[track_caller]
-    fn index(&self, range: ops::Range<usize>) -> &Wtf8 {
+    fn index(&self, range: ops::Range<usize>) -> &Self {
         // is_code_point_boundary checks that the index is in [0, .len()]
         if range.start <= range.end
             && is_code_point_boundary(self, range.start)
@@ -1261,11 +1314,11 @@ impl ops::Index<ops::Range<usize>> for Wtf8 {
 /// Panics when `begin` is not at a code point boundary,
 /// or is beyond the end of the string.
 impl ops::Index<ops::RangeFrom<usize>> for Wtf8 {
-    type Output = Wtf8;
+    type Output = Self;
 
     #[inline]
     #[track_caller]
-    fn index(&self, range: ops::RangeFrom<usize>) -> &Wtf8 {
+    fn index(&self, range: ops::RangeFrom<usize>) -> &Self {
         // is_code_point_boundary checks that the index is in [0, .len()]
         if is_code_point_boundary(self, range.start) {
             unsafe { slice_unchecked(self, range.start, self.len()) }
@@ -1282,11 +1335,11 @@ impl ops::Index<ops::RangeFrom<usize>> for Wtf8 {
 /// Panics when `end` is not at a code point boundary,
 /// or is beyond the end of the string.
 impl ops::Index<ops::RangeTo<usize>> for Wtf8 {
-    type Output = Wtf8;
+    type Output = Self;
 
     #[inline]
     #[track_caller]
-    fn index(&self, range: ops::RangeTo<usize>) -> &Wtf8 {
+    fn index(&self, range: ops::RangeTo<usize>) -> &Self {
         // is_code_point_boundary checks that the index is in [0, .len()]
         if is_code_point_boundary(self, range.end) {
             unsafe { slice_unchecked(self, 0, range.end) }
@@ -1297,10 +1350,10 @@ impl ops::Index<ops::RangeTo<usize>> for Wtf8 {
 }
 
 impl ops::Index<ops::RangeFull> for Wtf8 {
-    type Output = Wtf8;
+    type Output = Self;
 
     #[inline]
-    fn index(&self, _range: ops::RangeFull) -> &Wtf8 {
+    fn index(&self, _range: ops::RangeFull) -> &Self {
         self
     }
 }
@@ -1351,9 +1404,10 @@ pub fn check_utf8_boundary(slice: &Wtf8, index: usize) {
     }
     if slice.bytes[index + 1] >= 0xA0 {
         // There's a surrogate after index. Now check before index.
-        if index >= 3 && slice.bytes[index - 3] == 0xED && slice.bytes[index - 2] >= 0xA0 {
-            panic!("byte index {index} lies between surrogate codepoints");
-        }
+        assert!(
+            !(index >= 3 && slice.bytes[index - 3] == 0xED && slice.bytes[index - 2] >= 0xA0),
+            "byte index {index} lies between surrogate codepoints"
+        );
     }
 }
 
@@ -1363,6 +1417,7 @@ pub fn check_utf8_boundary(slice: &Wtf8, index: usize) {
 ///
 /// `begin` and `end` must be within bounds and on codepoint boundaries.
 #[inline]
+#[must_use]
 pub const unsafe fn slice_unchecked(s: &Wtf8, begin: usize, end: usize) -> &Wtf8 {
     // SAFETY: memory layout of a &[u8] and &Wtf8 are the same
     unsafe {
@@ -1431,6 +1486,7 @@ impl DoubleEndedIterator for Wtf8CodePoints<'_> {
 }
 
 impl<'a> Wtf8CodePoints<'a> {
+    #[must_use]
     pub fn as_wtf8(&self) -> &'a Wtf8 {
         unsafe { Wtf8::from_bytes_unchecked(self.bytes.as_slice()) }
     }
@@ -1578,6 +1634,7 @@ impl Hash for CodePoint {
 /// # Safety
 ///
 /// `value` must be valid WTF-8.
+#[must_use]
 pub unsafe fn from_boxed_wtf8_unchecked(value: Box<[u8]>) -> Box<Wtf8> {
     unsafe { Box::from_raw(Box::into_raw(value) as *mut Wtf8) }
 }
@@ -1628,7 +1685,7 @@ impl From<Box<ascii::AsciiStr>> for Box<Wtf8> {
 
 impl From<Box<Wtf8>> for Box<[u8]> {
     fn from(w: Box<Wtf8>) -> Self {
-        unsafe { Box::from_raw(Box::into_raw(w) as *mut [u8]) }
+        unsafe { Self::from_raw(Box::into_raw(w) as *mut [u8]) }
     }
 }
 
@@ -1640,7 +1697,7 @@ impl From<Wtf8Buf> for Box<Wtf8> {
 
 impl From<Box<Wtf8>> for Wtf8Buf {
     fn from(w: Box<Wtf8>) -> Self {
-        Wtf8Buf::from_box(w)
+        Self::from_box(w)
     }
 }
 
diff --git a/examples/call_between_rust_and_python.rs b/examples/call_between_rust_and_python.rs
index 3a7c0ce61..32b5a61b3 100644
--- a/examples/call_between_rust_and_python.rs
+++ b/examples/call_between_rust_and_python.rs
@@ -34,7 +34,7 @@ mod rust_py_module {
         s: String,
         python_person: PythonPerson,
         _vm: &VirtualMachine,
-    ) -> PyResult<RustStruct> {
+    ) -> RustStruct {
         println!(
             "Calling standalone rust function from python passing args:
 num: {},
@@ -42,9 +42,9 @@ string: {},
 python_person.name: {}",
             num, s, python_person.name
         );
-        Ok(RustStruct {
+        RustStruct {
             numbers: NumVec(vec![1, 2, 3, 4]),
-        })
+        }
     }
 
     #[derive(Debug, Clone)]
diff --git a/examples/freeze/main.rs b/examples/freeze/main.rs
index ab26a2bc8..ffbc45639 100644
--- a/examples/freeze/main.rs
+++ b/examples/freeze/main.rs
@@ -4,6 +4,7 @@ fn main() -> vm::PyResult<()> {
     vm::Interpreter::without_stdlib(Default::default()).enter(run)
 }
 
+#[expect(clippy::unnecessary_wraps)]
 fn run(vm: &vm::VirtualMachine) -> vm::PyResult<()> {
     let scope = vm.new_scope_with_builtins();
 
diff --git a/examples/mini_repl.rs b/examples/mini_repl.rs
index edbd6e149..1f8095aa9 100644
--- a/examples/mini_repl.rs
+++ b/examples/mini_repl.rs
@@ -6,7 +6,7 @@
 
 use rustpython_vm as vm;
 // these are needed for special memory shenanigans to let us share a variable with Python and Rust
-use std::sync::atomic::{AtomicBool, Ordering};
+use core::sync::atomic::{AtomicBool, Ordering};
 
 // This has to be a macro because it uses the py_compile macro,
 // which compiles python source to optimized bytecode at compile time, so that
diff --git a/examples/parse_folder.rs b/examples/parse_folder.rs
index 7ece0c740..05a3b2f36 100644
--- a/examples/parse_folder.rs
+++ b/examples/parse_folder.rs
@@ -8,11 +8,12 @@ extern crate env_logger;
 #[macro_use]
 extern crate log;
 
+use core::time::Duration;
 use ruff_python_parser::parse_module;
 use rustpython_compiler::ast;
 use std::{
     path::{Path, PathBuf},
-    time::{Duration, Instant},
+    time::Instant,
 };
 
 fn main() {
diff --git a/src/interpreter.rs b/src/interpreter.rs
index b9346ca1b..a8b03cba0 100644
--- a/src/interpreter.rs
+++ b/src/interpreter.rs
@@ -6,6 +6,7 @@ pub trait InterpreterBuilderExt {
     ///
     /// Requires the `stdlib` feature to be enabled.
     #[cfg(feature = "stdlib")]
+    #[must_use]
     fn init_stdlib(self) -> Self;
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index 918e33d79..ecad0a128 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -84,6 +84,7 @@ compile_error!(
 /// **Note**: This function provides no way to further initialize the VM after the builder is applied.
 /// All VM initialization (adding native modules, init hooks, etc.) must be done through the
 /// [`InterpreterBuilder`] parameter before calling this function.
+#[must_use]
 pub fn run(mut builder: InterpreterBuilder) -> ExitCode {
     env_logger::init();
 
@@ -369,7 +370,7 @@ fn run_rustpython(vm: &VirtualMachine, run_mode: RunMode) -> PyResult<()> {
         RunMode::InstallPip(installer) => install_pip(installer, scope.clone(), vm),
         RunMode::Script(script_path) => {
             // pymain_run_file_obj
-            debug!("Running script {}", script_path);
+            debug!("Running script {script_path}");
             run_file(vm, scope.clone(), &script_path)
         }
         RunMode::Repl => Ok(()),
@@ -467,7 +468,7 @@ mod tests {
     }
 
     #[test]
-    fn test_run_script() {
+    fn run_script() {
         interpreter().enter(|vm| {
             vm.unwrap_pyresult((|| {
                 let scope = vm.new_scope_with_main()?;
diff --git a/src/main.rs b/src/main.rs
index 01818ed97..32a8ccbdd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,6 +4,7 @@ use rustpython::{InterpreterBuilder, InterpreterBuilderExt};
 #[global_allocator]
 static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
 
+#[must_use]
 pub fn main() -> std::process::ExitCode {
     let mut config = InterpreterBuilder::new();
     #[cfg(feature = "stdlib")]
diff --git a/src/settings.rs b/src/settings.rs
index da36d9888..975204c00 100644
--- a/src/settings.rs
+++ b/src/settings.rs
@@ -1,9 +1,10 @@
-use lexopt::Arg::*;
+use core::cmp;
+use core::num::NonZeroI32;
+use core::str::FromStr;
+use lexopt::Arg::{Long, Short, Value};
 use lexopt::ValueExt;
 use rustpython_vm::{Settings, vm::CheckHashPycsMode};
-use std::num::NonZeroI32;
-use std::str::FromStr;
-use std::{cmp, env};
+use std::env;
 
 pub enum RunMode {
     Script(String),
@@ -113,7 +114,7 @@ fn parse_args() -> Result<(CliArgs, RunMode, Vec<String>), lexopt::Error> {
     let mut args = CliArgs::default();
     let mut parser = lexopt::Parser::from_env();
     fn argv(argv0: String, mut parser: lexopt::Parser) -> Result<Vec<String>, lexopt::Error> {
-        std::iter::once(Ok(argv0))
+        core::iter::once(Ok(argv0))
             .chain(parser.raw_args()?.map(|arg| arg.string()))
             .collect()
     }
@@ -532,7 +533,7 @@ fn dedent(input: &str) -> String {
         .collect();
 
     // Find maximum common whitespace prefix, if any.
-    for line in deblanked.iter() {
+    for line in &deblanked {
         if line.is_empty() {
             continue;
         }
diff --git a/src/shell/helper.rs b/src/shell/helper.rs
index c84c5437d..15fc75563 100644
--- a/src/shell/helper.rs
+++ b/src/shell/helper.rs
@@ -6,7 +6,7 @@ use rustpython_vm::{
     identifier,
 };
 
-pub struct ShellHelper<'vm> {
+pub(super) struct ShellHelper<'vm> {
     vm: &'vm VirtualMachine,
     globals: PyDictRef,
 }
@@ -54,7 +54,7 @@ fn split_idents_on_dot(line: &str) -> Option<(usize, Vec<String>)> {
 }
 
 impl<'vm> ShellHelper<'vm> {
-    pub const fn new(vm: &'vm VirtualMachine, globals: PyDictRef) -> Self {
+    pub(super) const fn new(vm: &'vm VirtualMachine, globals: PyDictRef) -> Self {
         ShellHelper { vm, globals }
     }
 
@@ -159,7 +159,7 @@ cfg_select! {
                 &self,
                 line: &str,
                 pos: usize,
-                _ctx: &Context,
+                _ctx: &Context<'_>,
             ) -> rustyline::Result<(usize, Vec<String>)> {
                 Ok(self
                     .complete_opt(&line[0..pos])
diff --git a/tests/benchmark_scripts.rs b/tests/benchmark_scripts.rs
index 89166a025..786c70942 100644
--- a/tests/benchmark_scripts.rs
+++ b/tests/benchmark_scripts.rs
@@ -1,4 +1,7 @@
 // cspell:ignore pyperformance nqueens pidigits
+
+#![allow(clippy::tests_outside_test_module)]
+
 use rustpython::{InterpreterBuilder, InterpreterBuilderExt};
 use std::{fs, path::Path};