diff --git a/crates/stdlib/src/binascii.rs b/crates/stdlib/src/binascii.rs
index 5deae90d5a1..bbeaa331e4c 100644
--- a/crates/stdlib/src/binascii.rs
+++ b/crates/stdlib/src/binascii.rs
@@ -2,6 +2,8 @@
 
 pub(super) use decl::crc32;
 pub(crate) use decl::module_def;
+
+use rustpython_common::wtf8::Wtf8Buf;
 use rustpython_vm::{VirtualMachine, builtins::PyBaseExceptionRef, convert::ToPyException};
 
 const PAD: u8 = 61u8;
@@ -16,6 +18,7 @@ mod decl {
         convert::ToPyException,
         function::{ArgAsciiBuffer, ArgBytesLike, OptionalArg},
     };
+
     use base64::Engine;
     use itertools::Itertools;
 
@@ -33,7 +36,7 @@ mod decl {
         vm.ctx.new_exception_type("binascii", "Incomplete", None)
     }
 
-    fn hex_nibble(n: u8) -> u8 {
+    const fn hex_nibble(n: u8) -> u8 {
         match n {
             0..=9 => b'0' + n,
             10..=15 => b'a' + (n - 10),
@@ -174,10 +177,7 @@ mod decl {
     fn unhexlify(data: ArgAsciiBuffer, vm: &VirtualMachine) -> PyResult<Vec<u8>> {
         data.with_ref(|hex_bytes| {
             if hex_bytes.len() % 2 != 0 {
-                return Err(super::new_binascii_error(
-                    "Odd-length string".to_owned(),
-                    vm,
-                ));
+                return Err(super::new_binascii_error("Odd-length string", vm));
             }
 
             let mut unhex = Vec::<u8>::with_capacity(hex_bytes.len() / 2);
@@ -185,10 +185,7 @@ mod decl {
                 if let (Some(n1), Some(n2)) = (unhex_nibble(*n1), unhex_nibble(*n2)) {
                     unhex.push((n1 << 4) | n2);
                 } else {
-                    return Err(super::new_binascii_error(
-                        "Non-hexadecimal digit found".to_owned(),
-                        vm,
-                    ));
+                    return Err(super::new_binascii_error("Non-hexadecimal digit found", vm));
                 }
             }
 
@@ -264,10 +261,10 @@ mod decl {
 
     #[pyfunction]
     fn a2b_base64(args: A2bBase64Args, vm: &VirtualMachine) -> PyResult<Vec<u8>> {
-        #[rustfmt::skip]
         // Converts between ASCII and base-64 characters. The index of a given number yields the
         // number in ASCII while the value of said index yields the number in base-64. For example
         // "=" is 61 in ASCII but 0 (since it's the pad character) in base-64, so BASE64_TABLE[61] == 0
+        #[rustfmt::skip]
         const BASE64_TABLE: [i8; 256] = [
             -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
             -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
@@ -398,7 +395,7 @@ mod decl {
             if [b'\r', b'\n'].contains(c) {
                 return Ok(0);
             }
-            return Err(super::new_binascii_error("Illegal char".to_owned(), vm));
+            return Err(super::new_binascii_error("Illegal char", vm));
         }
         Ok((*c - b' ') & 0x3f)
     }
@@ -757,8 +754,7 @@ mod decl {
 
             // Allocate the buffer
             let mut res = Vec::<u8>::with_capacity(length);
-            let trailing_garbage_error =
-                || Err(super::new_binascii_error("Trailing garbage".to_owned(), vm));
+            let trailing_garbage_error = || Err(super::new_binascii_error("Trailing garbage", vm));
 
             for chunk in b.get(1..).unwrap_or_default().chunks(4) {
                 let (char_a, char_b, char_c, char_d) = {
@@ -823,10 +819,7 @@ mod decl {
         data.with_ref(|b| {
             let length = b.len();
             if length > 45 {
-                return Err(super::new_binascii_error(
-                    "At most 45 bytes at once".to_owned(),
-                    vm,
-                ));
+                return Err(super::new_binascii_error("At most 45 bytes at once", vm));
             }
             let mut res = Vec::<u8>::with_capacity(2 + length.div_ceil(3) * 4);
             res.push(uu_b2a(length as u8, backtick));
@@ -850,7 +843,7 @@ mod decl {
 
 struct Base64DecodeError(base64::DecodeError);
 
-fn new_binascii_error(msg: String, vm: &VirtualMachine) -> PyBaseExceptionRef {
+fn new_binascii_error<T: Into<Wtf8Buf>>(msg: T, vm: &VirtualMachine) -> PyBaseExceptionRef {
     vm.new_exception_msg(decl::error_type(vm), msg.into())
 }
 
diff --git a/crates/stdlib/src/unicodedata.rs b/crates/stdlib/src/unicodedata.rs
index 0c43f5a2290..50731e606d7 100644
--- a/crates/stdlib/src/unicodedata.rs
+++ b/crates/stdlib/src/unicodedata.rs
@@ -274,11 +274,10 @@ mod unicodedata {
 
         #[pymethod]
         fn decomposition(&self, character: PyStrRef, vm: &VirtualMachine) -> PyResult<String> {
-            let ch = match self.extract_char(character, vm)?.and_then(|c| c.to_char()) {
-                Some(ch) => ch,
-                None => return Ok(String::new()),
+            let Some(ch) = self.extract_char(character, vm)?.and_then(|c| c.to_char()) else {
+                return Ok(String::new());
             };
-            let chars: Vec<char> = ch.decomposition_map().collect();
+            let chars = ch.decomposition_map().collect::<Vec<char>>();
             // If decomposition maps to just the character itself, there's no decomposition
             if chars.len() == 1 && chars[0] == ch {
                 return Ok(String::new());
@@ -356,7 +355,7 @@ mod unicodedata {
         }
     }
 
-    fn decomposition_type_tag(dt: DecompositionType) -> &'static str {
+    const fn decomposition_type_tag(dt: DecompositionType) -> &'static str {
         match dt {
             DecompositionType::Canonical => "canonical",
             DecompositionType::Compat => "compat",
diff --git a/crates/vm/src/builtins/dict.rs b/crates/vm/src/builtins/dict.rs
index 4b2b7c7541e..605322ef07f 100644
--- a/crates/vm/src/builtins/dict.rs
+++ b/crates/vm/src/builtins/dict.rs
@@ -855,6 +855,7 @@ impl Iterator for DictIntoIter {
         (l, Some(l))
     }
 }
+
 impl ExactSizeIterator for DictIntoIter {
     fn len(&self) -> usize {
         self.dict.entries.len_from_entry_index(self.position)
@@ -886,6 +887,7 @@ impl Iterator for DictIter<'_> {
         (l, Some(l))
     }
 }
+
 impl ExactSizeIterator for DictIter<'_> {
     fn len(&self) -> usize {
         self.dict.entries.len_from_entry_index(self.position)
@@ -1266,6 +1268,7 @@ trait ViewSetOps: DictView {
 }
 
 impl ViewSetOps for PyDictKeys {}
+
 #[pyclass(
     flags(DISALLOW_INSTANTIATION),
     with(
diff --git a/crates/vm/src/builtins/list.rs b/crates/vm/src/builtins/list.rs
index f4af27ea492..4179f7ef949 100644
--- a/crates/vm/src/builtins/list.rs
+++ b/crates/vm/src/builtins/list.rs
@@ -533,7 +533,7 @@ impl AsSequence for PyList {
                 }
                 .map_err(|e| {
                     if e.class().is(vm.ctx.exceptions.index_error) {
-                        vm.new_index_error("list assignment index out of range".to_owned())
+                        vm.new_index_error("list assignment index out of range")
                     } else {
                         e
                     }
diff --git a/crates/vm/src/stdlib/_collections.rs b/crates/vm/src/stdlib/_collections.rs
index e5127431c8b..4f580ab5dff 100644
--- a/crates/vm/src/stdlib/_collections.rs
+++ b/crates/vm/src/stdlib/_collections.rs
@@ -365,7 +365,7 @@ mod _collections {
                 })
             } else {
                 Err(vm.new_type_error(format!(
-                    "can only concatenate deque (not \"{}\") to deque",
+                    r#"can only concatenate deque (not "{}") to deque"#,
                     other.class().name()
                 )))
             }
@@ -503,11 +503,13 @@ mod _collections {
                         .concat(other, vm)
                         .map(|x| x.into_ref(&vm.ctx).into())
                 }),
+
                 repeat: atomic_func!(|seq, n, vm| {
                     PyDeque::sequence_downcast(seq)
                         .__mul__(n, vm)
                         .map(|x| x.into_ref(&vm.ctx).into())
                 }),
+
                 item: atomic_func!(|seq, i, vm| PyDeque::sequence_downcast(seq).__getitem__(i, vm)),
                 ass_item: atomic_func!(|seq, i, value, vm| {
                     let zelf = PyDeque::sequence_downcast(seq);
@@ -517,14 +519,17 @@ mod _collections {
                         zelf.__delitem__(i, vm)
                     }
                 }),
+
                 contains: atomic_func!(
                     |seq, needle, vm| PyDeque::sequence_downcast(seq)._contains(needle, vm)
                 ),
+
                 inplace_concat: atomic_func!(|seq, other, vm| {
                     let zelf = PyDeque::sequence_downcast(seq);
                     zelf._extend(other, vm)?;
                     Ok(zelf.to_owned().into())
                 }),
+
                 inplace_repeat: atomic_func!(|seq, n, vm| {
                     let zelf = PyDeque::sequence_downcast(seq);
                     PyDeque::__imul__(zelf.to_owned(), n, vm).map(|x| x.into())
@@ -545,6 +550,7 @@ mod _collections {
             if let Some(res) = op.identical_optimization(zelf, other) {
                 return Ok(res.into());
             }
+
             let other = class_or_notimplemented!(Self, other);
             let lhs = zelf.borrow_deque();
             let rhs = other.borrow_deque();
@@ -573,6 +579,7 @@ mod _collections {
             if zelf.__len__() == 0 {
                 return Ok(vm.ctx.new_str(format!("{class_name}([{closing_part})")));
             }
+
             if let Some(_guard) = ReprGuard::enter(vm, zelf.as_object()) {
                 Ok(vm.ctx.new_str(collection_repr(
                     Some(&class_name),
diff --git a/crates/vm/src/stdlib/_io.rs b/crates/vm/src/stdlib/_io.rs
index 4d16c104694..c6bee82c223 100644
--- a/crates/vm/src/stdlib/_io.rs
+++ b/crates/vm/src/stdlib/_io.rs
@@ -188,18 +188,18 @@ mod _io {
         result.map(Some)
     }
 
-    pub(super) fn new_unsupported_operation(
+    pub(super) fn new_unsupported_operation<T: Into<String>>(
+        msg: T,
         vm: &VirtualMachine,
-        msg: String,
     ) -> PyBaseExceptionRef {
-        vm.new_os_subtype_error(unsupported_operation().to_owned(), None, msg)
+        vm.new_os_subtype_error(unsupported_operation().to_owned(), None, msg.into())
             .upcast()
     }
 
     fn _unsupported<T>(vm: &VirtualMachine, zelf: &PyObject, operation: &str) -> PyResult<T> {
         Err(new_unsupported_operation(
-            vm,
             format!("{}.{}() not supported", zelf.class().name(), operation),
+            vm,
         ))
     }
 
@@ -363,8 +363,8 @@ mod _io {
             Ok(())
         } else {
             Err(new_unsupported_operation(
+                "File or stream is not readable",
                 vm,
-                "File or stream is not readable".to_owned(),
             ))
         }
     }
@@ -374,8 +374,8 @@ mod _io {
             Ok(())
         } else {
             Err(new_unsupported_operation(
+                "File or stream is not writable.",
                 vm,
-                "File or stream is not writable.".to_owned(),
             ))
         }
     }
@@ -385,8 +385,8 @@ mod _io {
             Ok(())
         } else {
             Err(new_unsupported_operation(
+                "File or stream is not seekable",
                 vm,
-                "File or stream is not seekable".to_owned(),
             ))
         }
     }
@@ -1680,7 +1680,7 @@ mod _io {
             let mut data = zelf.lock(vm)?;
             data.check_init(vm)?;
             if !data.writable() {
-                return Err(new_unsupported_operation(vm, "truncate".to_owned()));
+                return Err(new_unsupported_operation("truncate", vm));
             }
             data.flush_rewind(vm)?;
             let res = vm.call_method(data.raw.as_ref().unwrap(), "truncate", (pos,))?;
@@ -3063,9 +3063,8 @@ mod _io {
                     || data.decoded_chars_used.chars != 0)
             {
                 return Err(new_unsupported_operation(
+                    "cannot reconfigure encoding or newline after reading from the stream",
                     vm,
-                    "cannot reconfigure encoding or newline after reading from the stream"
-                        .to_owned(),
                 ));
             }
 
@@ -3203,8 +3202,8 @@ mod _io {
 
             if !textio.seekable {
                 return Err(new_unsupported_operation(
+                    "underlying stream is not seekable",
                     vm,
-                    "underlying stream is not seekable".to_owned(),
                 ));
             }
 
@@ -3217,8 +3216,8 @@ mod _io {
                         vm.call_method(&textio.buffer, "tell", ())?
                     } else {
                         return Err(new_unsupported_operation(
+                            "can't do nonzero cur-relative seeks",
                             vm,
-                            "can't do nonzero cur-relative seeks".to_owned(),
                         ));
                     }
                 }
@@ -3241,8 +3240,8 @@ mod _io {
                         return Ok(res);
                     }
                     return Err(new_unsupported_operation(
+                        "can't do nonzero end-relative seeks",
                         vm,
-                        "can't do nonzero end-relative seeks".to_owned(),
                     ));
                 }
                 _ => {
@@ -3312,8 +3311,8 @@ mod _io {
             let mut textio = zelf.lock(vm)?;
             if !textio.seekable {
                 return Err(new_unsupported_operation(
+                    "underlying stream is not seekable",
                     vm,
-                    "underlying stream is not seekable".to_owned(),
                 ));
             }
             if !textio.telling {
@@ -3444,7 +3443,7 @@ mod _io {
             let decoder = textio
                 .decoder
                 .clone()
-                .ok_or_else(|| new_unsupported_operation(vm, "not readable".to_owned()))?;
+                .ok_or_else(|| new_unsupported_operation("not readable", vm))?;
 
             textio.write_pending(vm)?;
 
@@ -3495,7 +3494,7 @@ mod _io {
             let (encoder, encode_func) = textio
                 .encoder
                 .as_ref()
-                .ok_or_else(|| new_unsupported_operation(vm, "not writable".to_owned()))?;
+                .ok_or_else(|| new_unsupported_operation("not writable", vm))?;
 
             let char_len = obj.char_len();
 
@@ -3861,7 +3860,7 @@ mod _io {
             let decoder = self
                 .decoder
                 .as_ref()
-                .ok_or_else(|| new_unsupported_operation(vm, "not readable".to_owned()))?;
+                .ok_or_else(|| new_unsupported_operation("not readable", vm))?;
 
             let dec_state = if self.telling {
                 let state = vm.call_method(decoder, "getstate", ())?;
@@ -5101,8 +5100,8 @@ mod _io {
         }
         .ok_or_else(|| {
             new_unsupported_operation(
+                "Couldn't get FileIO, io.open likely isn't supported on your platform",
                 vm,
-                "Couldn't get FileIO, io.open likely isn't supported on your platform".to_owned(),
             )
         })?;
         let raw = PyType::call(
@@ -5586,8 +5585,8 @@ mod fileio {
         ) -> PyResult<Option<Vec<u8>>> {
             if !zelf.mode.load().contains(host_io::FileMode::READABLE) {
                 return Err(new_unsupported_operation(
+                    "File or stream is not readable",
                     vm,
-                    "File or stream is not readable".to_owned(),
                 ));
             }
             let handle = zelf.get_fd(vm)?;
@@ -5644,8 +5643,8 @@ mod fileio {
         ) -> PyResult<Option<usize>> {
             if !zelf.mode.load().contains(host_io::FileMode::READABLE) {
                 return Err(new_unsupported_operation(
+                    "File or stream is not readable",
                     vm,
-                    "File or stream is not readable".to_owned(),
                 ));
             }
 
@@ -5679,8 +5678,8 @@ mod fileio {
         ) -> PyResult<Option<usize>> {
             if !zelf.mode.load().contains(host_io::FileMode::WRITABLE) {
                 return Err(new_unsupported_operation(
+                    "File or stream is not writable",
                     vm,
-                    "File or stream is not writable".to_owned(),
                 ));
             }
 
@@ -6219,8 +6218,8 @@ mod winconsoleio {
             let fd = self.get_fd(vm)?;
             if !self.readable.load() {
                 return Err(new_unsupported_operation(
+                    "Console buffer does not support reading",
                     vm,
-                    "Console buffer does not support reading".to_owned(),
                 ));
             }
             let mut buf_ref = buffer.borrow_buf_mut();
@@ -6267,8 +6266,8 @@ mod winconsoleio {
             }
             if !self.readable.load() {
                 return Err(new_unsupported_operation(
+                    "Console buffer does not support reading",
                     vm,
-                    "Console buffer does not support reading".to_owned(),
                 ));
             }
             let size = size.unwrap_or(-1);
@@ -6310,8 +6309,8 @@ mod winconsoleio {
             }
             if !self.writable.load() {
                 return Err(new_unsupported_operation(
+                    "Console buffer does not support writing",
                     vm,
-                    "Console buffer does not support writing".to_owned(),
                 ));
             }
 
diff --git a/crates/vm/src/stdlib/_thread.rs b/crates/vm/src/stdlib/_thread.rs
index 7291026ed58..93d42676b4e 100644
--- a/crates/vm/src/stdlib/_thread.rs
+++ b/crates/vm/src/stdlib/_thread.rs
@@ -152,6 +152,7 @@ pub(crate) mod _thread {
         fn acquire(&self, args: AcquireArgs, vm: &VirtualMachine) -> PyResult<bool> {
             acquire_lock_impl!(&self.mu, args, vm)
         }
+
         #[pymethod]
         #[pymethod(name = "release_lock")]
         fn release(&self, vm: &VirtualMachine) -> PyResult<()> {
@@ -240,6 +241,7 @@ pub(crate) mod _thread {
             }
             Ok(result)
         }
+
         #[pymethod]
         #[pymethod(name = "release_lock")]
         fn release(&self, vm: &VirtualMachine) -> PyResult<()> {
@@ -413,34 +415,36 @@ pub(crate) mod _thread {
 
     /// Get OS-level thread ID (pthread_self on Unix)
     /// This is important for fork compatibility - the ID must remain stable after fork
-    #[cfg(unix)]
-    fn current_thread_id() -> u64 {
-        host_thread::current_thread_id()
-    }
-
-    #[cfg(not(unix))]
     fn current_thread_id() -> u64 {
-        thread_to_rust_id(&thread::current())
+        cfg_select! {
+            unix => host_thread::current_thread_id(),
+            _ => thread_to_rust_id(&thread::current()),
+        }
     }
 
     /// Convert Rust thread to ID (used for non-unix platforms)
     #[cfg(not(unix))]
     fn thread_to_rust_id(t: &thread::Thread) -> u64 {
         use core::hash::{Hash, Hasher};
+
         struct U64Hash {
             v: Option<u64>,
         }
+
         impl Hasher for U64Hash {
             fn write(&mut self, _: &[u8]) {
                 unreachable!()
             }
+
             fn write_u64(&mut self, i: u64) {
                 self.v = Some(i);
             }
+
             fn finish(&self) -> u64 {
                 self.v.expect("should have written a u64")
             }
         }
+
         let mut h = U64Hash { v: None };
         t.id().hash(&mut h);
         h.finish()
@@ -472,12 +476,14 @@ pub(crate) mod _thread {
         if !f_args.kwargs.is_empty() {
             return Err(vm.new_type_error("start_new_thread() takes no keyword arguments"));
         }
+
         let given = f_args.args.len();
         if given < 2 {
             return Err(vm.new_type_error(format!(
                 "start_new_thread expected at least 2 arguments, got {given}"
             )));
         }
+
         if given > 3 {
             return Err(vm.new_type_error(format!(
                 "start_new_thread expected at most 3 arguments, got {given}"
@@ -491,9 +497,11 @@ pub(crate) mod _thread {
         if func_obj.to_callable().is_none() {
             return Err(vm.new_type_error("first arg must be callable"));
         }
+
         if !args_obj.fast_isinstance(vm.ctx.types.tuple_type) {
             return Err(vm.new_type_error("2nd arg must be a tuple"));
         }
+
         if kwargs_obj
             .as_ref()
             .is_some_and(|obj| !obj.fast_isinstance(vm.ctx.types.dict_type))
@@ -1537,13 +1545,12 @@ pub(crate) mod _thread {
                 })
                 .min_by_key(|(distance, _)| *distance)
                 .map(|(_, candidate)| candidate);
-            let msg = if let Some(suggestion) = suggestion {
-                format!(
-                    "start_joinable_thread() got an unexpected keyword argument '{unexpected}'. Did you mean '{suggestion}'?"
-                )
-            } else {
-                format!("start_joinable_thread() got an unexpected keyword argument '{unexpected}'")
-            };
+
+            let msg_suffix =
+                suggestion.map_or_else(String::new, |s| format!(". Did you mean '{s}'?"));
+            let msg = format!(
+                "start_joinable_thread() got an unexpected keyword argument '{unexpected}'{msg_suffix}"
+            );
             return Err(vm.new_type_error(msg));
         }
 
diff --git a/crates/vm/src/stdlib/_weakref.rs b/crates/vm/src/stdlib/_weakref.rs
index e7e030b2b01..4db8970ba70 100644
--- a/crates/vm/src/stdlib/_weakref.rs
+++ b/crates/vm/src/stdlib/_weakref.rs
@@ -17,18 +17,22 @@ mod _weakref {
     fn ref_(vm: &VirtualMachine) -> PyTypeRef {
         vm.ctx.types.weakref_type.to_owned()
     }
+
     #[pyattr]
     fn proxy(vm: &VirtualMachine) -> PyTypeRef {
         vm.ctx.types.weakproxy_type.to_owned()
     }
+
     #[pyattr(name = "ReferenceType")]
     fn reference_type(vm: &VirtualMachine) -> PyTypeRef {
         vm.ctx.types.weakref_type.to_owned()
     }
+
     #[pyattr(name = "ProxyType")]
     fn proxy_type(vm: &VirtualMachine) -> PyTypeRef {
         vm.ctx.types.weakproxy_type.to_owned()
     }
+
     #[pyattr(name = "CallableProxyType")]
     fn callable_proxy_type(vm: &VirtualMachine) -> PyTypeRef {
         vm.ctx.types.weakproxy_type.to_owned()
@@ -41,10 +45,8 @@ mod _weakref {
 
     #[pyfunction]
     fn getweakrefs(obj: PyObjectRef) -> Vec<PyObjectRef> {
-        match obj.get_weak_references() {
-            Some(v) => v.into_iter().map(Into::into).collect(),
-            None => vec![],
-        }
+        obj.get_weak_references()
+            .map_or_else(Vec::new, |v| v.into_iter().map(Into::into).collect())
     }
 
     #[pyfunction]
diff --git a/crates/vm/src/stdlib/builtins.rs b/crates/vm/src/stdlib/builtins.rs
index cfb9562b793..0bd04f332b5 100644
--- a/crates/vm/src/stdlib/builtins.rs
+++ b/crates/vm/src/stdlib/builtins.rs
@@ -128,7 +128,7 @@ mod builtins {
             let hash_pos = line.iter().position(|&b| b == b'#')?;
             if !line[..hash_pos]
                 .iter()
-                .all(|&b| b == b' ' || b == b'\t' || b == b'\x0c' || b == b'\r')
+                .all(|&b| matches!(b, b' ' | b'\t' | b'\x0c' | b'\r'))
             {
                 return None;
             }
@@ -139,8 +139,7 @@ mod builtins {
             let after_coding = &after_hash[coding_pos + 6..];
 
             // Next char must be ':' or '='
-            let rest = if after_coding.first() == Some(&b':') || after_coding.first() == Some(&b'=')
-            {
+            let rest = if matches!(after_coding.first(), Some(b':' | b'=')) {
                 &after_coding[1..]
             } else {
                 return None;
@@ -150,15 +149,15 @@ mod builtins {
             let rest = rest
                 .iter()
                 .copied()
-                .skip_while(|&b| b == b' ' || b == b'\t')
+                .skip_while(|&b| matches!(b, b' ' | b'\t'))
                 .collect::<Vec<_>>();
 
             // Read encoding name: [-\w.]+
-            let name: String = rest
+            let name = rest
                 .iter()
-                .take_while(|&&b| b.is_ascii_alphanumeric() || b == b'-' || b == b'_' || b == b'.')
+                .take_while(|&&b| b.is_ascii_alphanumeric() || matches!(b, b'-' | b'_' | b'.'))
                 .map(|&b| b as char)
-                .collect();
+                .collect::<String>();
 
             if name.is_empty() {
                 None
@@ -179,10 +178,10 @@ mod builtins {
             // Only check second line if first line is blank or a comment
             let trimmed = first
                 .iter()
-                .skip_while(|&&b| b == b' ' || b == b'\t' || b == b'\x0c' || b == b'\r')
-                .copied()
-                .collect::<Vec<_>>();
-            if !trimmed.is_empty() && trimmed[0] != b'#' {
+                .find(|&&b| !matches!(b, b' ' | b'\t' | b'\x0c' | b'\r'))
+                .copied();
+
+            if trimmed.is_some_and(|b| b != b'#') {
                 return None;
             }
         }
@@ -350,7 +349,7 @@ mod builtins {
 
                 #[cfg(not(feature = "rustpython-codegen"))]
                 {
-                    return Err(vm.new_type_error(CODEGEN_NOT_SUPPORTED.to_owned()));
+                    return Err(vm.new_type_error(CODEGEN_NOT_SUPPORTED));
                 }
                 #[cfg(feature = "rustpython-codegen")]
                 {
@@ -368,10 +367,10 @@ mod builtins {
             }
 
             #[cfg(not(feature = "parser"))]
-            {
-                const PARSER_NOT_SUPPORTED: &str = "can't compile() source code when the `parser` feature of rustpython is disabled";
-                Err(vm.new_type_error(PARSER_NOT_SUPPORTED.to_owned()))
-            }
+            return Err(vm.new_type_error(
+                "can't compile() source code when the `parser` feature of rustpython is disabled",
+            ));
+
             #[cfg(feature = "parser")]
             {
                 use crate::convert::ToPyException;
@@ -398,7 +397,7 @@ mod builtins {
                 if (flags & _ast::PY_CF_ONLY_AST).is_zero() {
                     #[cfg(not(feature = "compiler"))]
                     {
-                        Err(vm.new_value_error(CODEGEN_NOT_SUPPORTED.to_owned()))
+                        Err(vm.new_value_error(CODEGEN_NOT_SUPPORTED))
                     }
                     #[cfg(feature = "compiler")]
                     {
@@ -470,23 +469,22 @@ mod builtins {
         feature_version: OptionalArg<i32>,
         vm: &VirtualMachine,
     ) -> PyResult<Option<ruff_python_ast::PythonVersion>> {
-        let minor = match feature_version.into_option() {
-            Some(minor) => minor,
-            None => return Ok(None),
+        let Some(minor) = feature_version.into_option() else {
+            return Ok(None);
         };
 
         if minor < 0 {
             return Ok(None);
         }
 
-        let minor = u8::try_from(minor)
-            .map_err(|_| vm.new_value_error("compile() _feature_version out of range"))?;
-        Ok(Some(ruff_python_ast::PythonVersion { major: 3, minor }))
+        u8::try_from(minor)
+            .map(|v| Some(ruff_python_ast::PythonVersion { major: 3, minor: v }))
+            .map_err(|_| vm.new_value_error("compile() _feature_version out of range"))
     }
 
     #[pyfunction]
     fn delattr(obj: PyObjectRef, attr: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
-        let attr = attr.try_to_ref::<PyStr>(vm).map_err(|_e| {
+        let attr = attr.try_to_ref::<PyStr>(vm).map_err(|_| {
             vm.new_type_error(format!(
                 "attribute name must be string, not '{}'",
                 attr.class().name()
@@ -514,40 +512,42 @@ mod builtins {
     }
 
     impl ScopeArgs {
+        fn validate_globals_dict(
+            globals: &PyObject,
+            vm: &VirtualMachine,
+            func_name: &'static str,
+        ) -> PyResult<()> {
+            if globals.fast_isinstance(vm.ctx.types.dict_type) {
+                return Ok(());
+            }
+
+            let msg = match func_name {
+                "eval" => {
+                    let is_mapping = globals.mapping_unchecked().check();
+                    if is_mapping {
+                        "globals must be a real dict; try eval(expr, {}, mapping)".into()
+                    } else {
+                        "globals must be a dict".into()
+                    }
+                }
+                "exec" => format!(
+                    "exec() globals must be a dict, not {}",
+                    globals.class().name()
+                ),
+                _ => "globals must be a dict".into(),
+            };
+
+            Err(vm.new_type_error(msg))
+        }
+
         fn make_scope(
             self,
             vm: &VirtualMachine,
             func_name: &'static str,
         ) -> PyResult<crate::scope::Scope> {
-            fn validate_globals_dict(
-                globals: &PyObject,
-                vm: &VirtualMachine,
-                func_name: &'static str,
-            ) -> PyResult<()> {
-                if !globals.fast_isinstance(vm.ctx.types.dict_type) {
-                    return Err(match func_name {
-                        "eval" => {
-                            let is_mapping = globals.mapping_unchecked().check();
-                            vm.new_type_error(if is_mapping {
-                                "globals must be a real dict; try eval(expr, {}, mapping)"
-                                    .to_owned()
-                            } else {
-                                "globals must be a dict".to_owned()
-                            })
-                        }
-                        "exec" => vm.new_type_error(format!(
-                            "exec() globals must be a dict, not {}",
-                            globals.class().name()
-                        )),
-                        _ => vm.new_type_error("globals must be a dict"),
-                    });
-                }
-                Ok(())
-            }
-
             let (globals, locals) = match self.globals {
                 Some(globals) => {
-                    validate_globals_dict(&globals, vm, func_name)?;
+                    Self::validate_globals_dict(&globals, vm, func_name)?;
 
                     let globals = PyDictRef::try_from_object(vm, globals)?;
                     if !globals.contains_key(identifier!(vm, __builtins__), vm) {
@@ -636,7 +636,7 @@ mod builtins {
                     .map_err(|err| vm.new_syntax_error(&err, Some(source)))?
             }
             #[cfg(not(feature = "rustpython-compiler"))]
-            Either::A(_) => return Err(vm.new_type_error(CODEGEN_NOT_SUPPORTED.to_owned())),
+            Either::A(_) => return Err(vm.new_type_error(CODEGEN_NOT_SUPPORTED)),
             Either::B(code_obj) => code_obj,
         };
 
diff --git a/crates/vm/src/stdlib/itertools.rs b/crates/vm/src/stdlib/itertools.rs
index 2cb23902ec9..8a78c698ed3 100644
--- a/crates/vm/src/stdlib/itertools.rs
+++ b/crates/vm/src/stdlib/itertools.rs
@@ -109,12 +109,11 @@ mod decl {
                     }
                 }
             };
-            match next {
-                Err(_) | Ok(PyIterReturn::StopIteration(_)) => {
-                    *zelf.source.write() = None;
-                }
-                _ => {}
+
+            if matches!(next, Err(_) | Ok(PyIterReturn::StopIteration(_))) {
+                *zelf.source.write() = None;
             };
+
             next
         }
     }
diff --git a/crates/vm/src/stdlib/typevar.rs b/crates/vm/src/stdlib/typevar.rs
index 81d32f852bc..da018b552e1 100644
--- a/crates/vm/src/stdlib/typevar.rs
+++ b/crates/vm/src/stdlib/typevar.rs
@@ -81,7 +81,6 @@ pub(crate) mod typevar {
     #[pyattr]
     #[pyclass(name = "TypeVar", module = "typing")]
     #[derive(Debug, PyPayload)]
-    #[allow(dead_code)]
     pub struct TypeVar {
         name: PyObjectRef, // TODO PyStrRef?
         bound: PyMutex<PyObjectRef>,
@@ -94,6 +93,7 @@ pub(crate) mod typevar {
         contravariant: bool,
         infer_variance: bool,
     }
+
     #[pyclass(
         flags(HAS_DICT, HAS_WEAKREF),
         with(AsNumber, Constructor, Representable)
@@ -267,7 +267,7 @@ pub(crate) mod typevar {
                 // Check if we have enough arguments
                 if args_tuple.len() <= index && zelf.has_default(vm) {
                     // Need to add default value
-                    let mut new_args: Vec<PyObjectRef> = args_tuple.iter().cloned().collect();
+                    let mut new_args = args_tuple.iter().cloned().collect::<Vec<PyObjectRef>>();
 
                     // Add default value at the correct position
                     while new_args.len() <= index {
@@ -367,7 +367,7 @@ pub(crate) mod typevar {
 
             // Check for unexpected keyword arguments
             if !kwargs.is_empty() {
-                let unexpected_keys: Vec<String> = kwargs.keys().map(|s| s.to_string()).collect();
+                let unexpected_keys = kwargs.keys().map(|s| s.to_string()).collect::<Vec<_>>();
                 return Err(vm.new_type_error(format!(
                     "TypeVar() got unexpected keyword argument(s): {}",
                     unexpected_keys.join(", ")
@@ -459,7 +459,6 @@ pub(crate) mod typevar {
     #[pyattr]
     #[pyclass(name = "ParamSpec", module = "typing")]
     #[derive(Debug, PyPayload)]
-    #[allow(dead_code)]
     pub struct ParamSpec {
         name: PyObjectRef,
         bound: Option<PyObjectRef>,
@@ -651,7 +650,7 @@ pub(crate) mod typevar {
 
             // Check for unexpected keyword arguments
             if !kwargs.is_empty() {
-                let unexpected_keys: Vec<String> = kwargs.keys().map(|s| s.to_string()).collect();
+                let unexpected_keys = kwargs.keys().map(|s| s.to_string()).collect::<Vec<_>>();
                 return Err(vm.new_type_error(format!(
                     "ParamSpec() got unexpected keyword argument(s): {}",
                     unexpected_keys.join(", ")
@@ -721,12 +720,12 @@ pub(crate) mod typevar {
     #[pyattr]
     #[pyclass(name = "TypeVarTuple", module = "typing")]
     #[derive(Debug, PyPayload)]
-    #[allow(dead_code)]
     pub struct TypeVarTuple {
         name: PyObjectRef,
         default_value: PyMutex<PyObjectRef>,
         evaluate_default: PyMutex<PyObjectRef>,
     }
+
     #[pyclass(
         flags(HAS_DICT, HAS_WEAKREF),
         with(Constructor, Representable, Iterable)
@@ -845,7 +844,7 @@ pub(crate) mod typevar {
 
             // Check for unexpected keyword arguments
             if !kwargs.is_empty() {
-                let unexpected_keys: Vec<String> = kwargs.keys().map(|s| s.to_string()).collect();
+                let unexpected_keys = kwargs.keys().map(|s| s.to_string()).collect::<Vec<_>>();
                 return Err(vm.new_type_error(format!(
                     "TypeVarTuple() got unexpected keyword argument(s): {}",
                     unexpected_keys.join(", ")
@@ -898,10 +897,10 @@ pub(crate) mod typevar {
     #[pyattr]
     #[pyclass(name = "ParamSpecArgs", module = "typing")]
     #[derive(Debug, PyPayload)]
-    #[allow(dead_code)]
     pub struct ParamSpecArgs {
         __origin__: PyObjectRef,
     }
+
     #[pyclass(with(Constructor, Representable, Comparable), flags(HAS_WEAKREF))]
     impl ParamSpecArgs {
         #[pymethod]
@@ -961,10 +960,10 @@ pub(crate) mod typevar {
     #[pyattr]
     #[pyclass(name = "ParamSpecKwargs", module = "typing")]
     #[derive(Debug, PyPayload)]
-    #[allow(dead_code)]
     pub struct ParamSpecKwargs {
         __origin__: PyObjectRef,
     }
+
     #[pyclass(with(Constructor, Representable, Comparable), flags(HAS_WEAKREF))]
     impl ParamSpecKwargs {
         #[pymethod]
@@ -1048,7 +1047,6 @@ pub(crate) mod typevar {
     #[pyattr]
     #[pyclass(name = "Generic", module = "typing")]
     #[derive(Debug, PyPayload)]
-    #[allow(dead_code)]
     pub struct Generic;
 
     #[pyclass(flags(BASETYPE, HEAPTYPE))]