diff --git a/pyo3-ffi/src/pyport.rs b/pyo3-ffi/src/pyport.rs
index 741b0db7..a144c67f 100644
--- a/pyo3-ffi/src/pyport.rs
+++ b/pyo3-ffi/src/pyport.rs
@@ -11,8 +11,8 @@ pub type Py_ssize_t = ::libc::ssize_t;
 pub type Py_hash_t = Py_ssize_t;
 pub type Py_uhash_t = ::libc::size_t;
 
-pub const PY_SSIZE_T_MIN: Py_ssize_t = std::isize::MIN as Py_ssize_t;
-pub const PY_SSIZE_T_MAX: Py_ssize_t = std::isize::MAX as Py_ssize_t;
+pub const PY_SSIZE_T_MIN: Py_ssize_t = isize::MIN as Py_ssize_t;
+pub const PY_SSIZE_T_MAX: Py_ssize_t = isize::MAX as Py_ssize_t;
 
 #[cfg(target_endian = "big")]
 pub const PY_BIG_ENDIAN: usize = 1;
diff --git a/pyo3-macros-backend/src/module.rs b/pyo3-macros-backend/src/module.rs
index 8ff720cc..3153279a 100644
--- a/pyo3-macros-backend/src/module.rs
+++ b/pyo3-macros-backend/src/module.rs
@@ -249,6 +249,7 @@ pub fn pymodule_module_impl(mut module: syn::ItemMod) -> Result<TokenStream> {
 
             #initialization
 
+            #[allow(unknown_lints, non_local_definitions)]
             impl MakeDef {
                 const fn make_def() -> #pyo3_path::impl_::pymodule::ModuleDef {
                     use #pyo3_path::impl_::pymodule as impl_;
@@ -333,6 +334,7 @@ pub fn pymodule_function_impl(mut function: syn::ItemFn) -> Result<TokenStream>
         // this avoids complications around the fact that the generated module has a different scope
         // (and `super` doesn't always refer to the outer scope, e.g. if the `#[pymodule] is
         // inside a function body)
+        #[allow(unknown_lints, non_local_definitions)]
         impl #ident::MakeDef {
             const fn make_def() -> #pyo3_path::impl_::pymodule::ModuleDef {
                 fn __pyo3_pymodule(module: &#pyo3_path::Bound<'_, #pyo3_path::types::PyModule>) -> #pyo3_path::PyResult<()> {
diff --git a/pyo3-macros-backend/src/pyfunction.rs b/pyo3-macros-backend/src/pyfunction.rs
index 9f9557a3..7c355533 100644
--- a/pyo3-macros-backend/src/pyfunction.rs
+++ b/pyo3-macros-backend/src/pyfunction.rs
@@ -273,6 +273,7 @@ pub fn impl_wrap_pyfunction(
         // this avoids complications around the fact that the generated module has a different scope
         // (and `super` doesn't always refer to the outer scope, e.g. if the `#[pyfunction] is
         // inside a function body)
+        #[allow(unknown_lints, non_local_definitions)]
         impl #name::MakeDef {
             const _PYO3_DEF: #pyo3_path::impl_::pymethods::PyMethodDef = #methoddef;
         }
diff --git a/pyo3-macros-backend/src/pymethod.rs b/pyo3-macros-backend/src/pymethod.rs
index abe8c7ac..7a4c54db 100644
--- a/pyo3-macros-backend/src/pymethod.rs
+++ b/pyo3-macros-backend/src/pymethod.rs
@@ -366,6 +366,7 @@ pub fn impl_py_method_def_new(
                     #deprecations
 
                     use #pyo3_path::impl_::pyclass::*;
+                    #[allow(unknown_lints, non_local_definitions)]
                     impl PyClassNewTextSignature<#cls> for PyClassImplCollector<#cls> {
                         #[inline]
                         fn new_text_signature(self) -> ::std::option::Option<&'static str> {
diff --git a/src/callback.rs b/src/callback.rs
index a56b268a..1e446039 100644
--- a/src/callback.rs
+++ b/src/callback.rs
@@ -4,7 +4,6 @@ use crate::err::{PyErr, PyResult};
 use crate::exceptions::PyOverflowError;
 use crate::ffi::{self, Py_hash_t};
 use crate::{IntoPy, PyObject, Python};
-use std::isize;
 use std::os::raw::c_int;
 
 /// A type which can be the return type of a python C-API callback
@@ -85,11 +84,7 @@ impl IntoPyCallbackOutput<()> for () {
 impl IntoPyCallbackOutput<ffi::Py_ssize_t> for usize {
     #[inline]
     fn convert(self, _py: Python<'_>) -> PyResult<ffi::Py_ssize_t> {
-        if self <= (isize::MAX as usize) {
-            Ok(self as isize)
-        } else {
-            Err(PyOverflowError::new_err(()))
-        }
+        self.try_into().map_err(|_err| PyOverflowError::new_err(()))
     }
 }
 
diff --git a/src/conversions/std/num.rs b/src/conversions/std/num.rs
index 44843141..e2072d21 100644
--- a/src/conversions/std/num.rs
+++ b/src/conversions/std/num.rs
@@ -445,7 +445,7 @@ mod test_128bit_integers {
     #[test]
     fn test_i128_max() {
         Python::with_gil(|py| {
-            let v = std::i128::MAX;
+            let v = i128::MAX;
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<i128>(py).unwrap());
             assert_eq!(v as u128, obj.extract::<u128>(py).unwrap());
@@ -456,7 +456,7 @@ mod test_128bit_integers {
     #[test]
     fn test_i128_min() {
         Python::with_gil(|py| {
-            let v = std::i128::MIN;
+            let v = i128::MIN;
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<i128>(py).unwrap());
             assert!(obj.extract::<i64>(py).is_err());
@@ -467,7 +467,7 @@ mod test_128bit_integers {
     #[test]
     fn test_u128_max() {
         Python::with_gil(|py| {
-            let v = std::u128::MAX;
+            let v = u128::MAX;
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<u128>(py).unwrap());
             assert!(obj.extract::<i128>(py).is_err());
@@ -495,7 +495,7 @@ mod test_128bit_integers {
     #[test]
     fn test_nonzero_i128_max() {
         Python::with_gil(|py| {
-            let v = NonZeroI128::new(std::i128::MAX).unwrap();
+            let v = NonZeroI128::new(i128::MAX).unwrap();
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<NonZeroI128>(py).unwrap());
             assert_eq!(
@@ -509,7 +509,7 @@ mod test_128bit_integers {
     #[test]
     fn test_nonzero_i128_min() {
         Python::with_gil(|py| {
-            let v = NonZeroI128::new(std::i128::MIN).unwrap();
+            let v = NonZeroI128::new(i128::MIN).unwrap();
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<NonZeroI128>(py).unwrap());
             assert!(obj.extract::<NonZeroI64>(py).is_err());
@@ -520,7 +520,7 @@ mod test_128bit_integers {
     #[test]
     fn test_nonzero_u128_max() {
         Python::with_gil(|py| {
-            let v = NonZeroU128::new(std::u128::MAX).unwrap();
+            let v = NonZeroU128::new(u128::MAX).unwrap();
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<NonZeroU128>(py).unwrap());
             assert!(obj.extract::<NonZeroI128>(py).is_err());
@@ -573,7 +573,7 @@ mod tests {
     #[test]
     fn test_u32_max() {
         Python::with_gil(|py| {
-            let v = std::u32::MAX;
+            let v = u32::MAX;
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<u32>(py).unwrap());
             assert_eq!(u64::from(v), obj.extract::<u64>(py).unwrap());
@@ -584,7 +584,7 @@ mod tests {
     #[test]
     fn test_i64_max() {
         Python::with_gil(|py| {
-            let v = std::i64::MAX;
+            let v = i64::MAX;
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<i64>(py).unwrap());
             assert_eq!(v as u64, obj.extract::<u64>(py).unwrap());
@@ -595,7 +595,7 @@ mod tests {
     #[test]
     fn test_i64_min() {
         Python::with_gil(|py| {
-            let v = std::i64::MIN;
+            let v = i64::MIN;
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<i64>(py).unwrap());
             assert!(obj.extract::<i32>(py).is_err());
@@ -606,7 +606,7 @@ mod tests {
     #[test]
     fn test_u64_max() {
         Python::with_gil(|py| {
-            let v = std::u64::MAX;
+            let v = u64::MAX;
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<u64>(py).unwrap());
             assert!(obj.extract::<i64>(py).is_err());
@@ -664,7 +664,7 @@ mod tests {
     #[test]
     fn test_nonzero_u32_max() {
         Python::with_gil(|py| {
-            let v = NonZeroU32::new(std::u32::MAX).unwrap();
+            let v = NonZeroU32::new(u32::MAX).unwrap();
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<NonZeroU32>(py).unwrap());
             assert_eq!(NonZeroU64::from(v), obj.extract::<NonZeroU64>(py).unwrap());
@@ -675,7 +675,7 @@ mod tests {
     #[test]
     fn test_nonzero_i64_max() {
         Python::with_gil(|py| {
-            let v = NonZeroI64::new(std::i64::MAX).unwrap();
+            let v = NonZeroI64::new(i64::MAX).unwrap();
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<NonZeroI64>(py).unwrap());
             assert_eq!(
@@ -689,7 +689,7 @@ mod tests {
     #[test]
     fn test_nonzero_i64_min() {
         Python::with_gil(|py| {
-            let v = NonZeroI64::new(std::i64::MIN).unwrap();
+            let v = NonZeroI64::new(i64::MIN).unwrap();
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<NonZeroI64>(py).unwrap());
             assert!(obj.extract::<NonZeroI32>(py).is_err());
@@ -700,7 +700,7 @@ mod tests {
     #[test]
     fn test_nonzero_u64_max() {
         Python::with_gil(|py| {
-            let v = NonZeroU64::new(std::u64::MAX).unwrap();
+            let v = NonZeroU64::new(u64::MAX).unwrap();
             let obj = v.to_object(py);
             assert_eq!(v, obj.extract::<NonZeroU64>(py).unwrap());
             assert!(obj.extract::<NonZeroI64>(py).is_err());
diff --git a/src/impl_/pyclass.rs b/src/impl_/pyclass.rs
index 1a144f73..1302834c 100644
--- a/src/impl_/pyclass.rs
+++ b/src/impl_/pyclass.rs
@@ -852,6 +852,7 @@ slot_fragment_trait! {
 #[macro_export]
 macro_rules! generate_pyclass_richcompare_slot {
     ($cls:ty) => {{
+        #[allow(unknown_lints, non_local_definitions)]
         impl $cls {
             #[allow(non_snake_case)]
             unsafe extern "C" fn __pymethod___richcmp____(
diff --git a/src/pycell/impl_.rs b/src/pycell/impl_.rs
index 378bec04..1bdd44b9 100644
--- a/src/pycell/impl_.rs
+++ b/src/pycell/impl_.rs
@@ -55,7 +55,7 @@ struct BorrowFlag(usize);
 
 impl BorrowFlag {
     pub(crate) const UNUSED: BorrowFlag = BorrowFlag(0);
-    const HAS_MUTABLE_BORROW: BorrowFlag = BorrowFlag(usize::max_value());
+    const HAS_MUTABLE_BORROW: BorrowFlag = BorrowFlag(usize::MAX);
     const fn increment(self) -> Self {
         Self(self.0 + 1)
     }
diff --git a/src/types/any.rs b/src/types/any.rs
index ab4f5727..a5ea4c80 100644
--- a/src/types/any.rs
+++ b/src/types/any.rs
@@ -2491,6 +2491,7 @@ class SimpleClass:
 
     #[cfg(feature = "macros")]
     #[test]
+    #[allow(unknown_lints, non_local_definitions)]
     fn test_hasattr_error() {
         use crate::exceptions::PyValueError;
         use crate::prelude::*;
diff --git a/tests/test_proto_methods.rs b/tests/test_proto_methods.rs
index dd707990..c5d73060 100644
--- a/tests/test_proto_methods.rs
+++ b/tests/test_proto_methods.rs
@@ -3,7 +3,7 @@
 use pyo3::exceptions::{PyAttributeError, PyIndexError, PyValueError};
 use pyo3::types::{PyDict, PyList, PyMapping, PySequence, PySlice, PyType};
 use pyo3::{prelude::*, py_run};
-use std::{isize, iter};
+use std::iter;
 
 #[path = "../src/tests/common.rs"]
 mod common;