Bump Rust edition to 2021 and make current Clippy happy.

Cargo.toml

@@ -11,7 +11,7 @@ documentation = "https://docs.rs/crate/pyo3/"
 categories = ["api-bindings", "development-tools::ffi"]
 license = "Apache-2.0"
 exclude = ["/.gitignore", ".cargo/config", "/codecov.yml", "/Makefile", "/pyproject.toml", "/noxfile.py", "/.github", "/tests/test_compile_error.rs", "/tests/ui"]
-edition = "2018"
+edition = "2021"
 rust-version = "1.56"
 
 [dependencies]
@@ -187,7 +187,6 @@ members = [
     "pytests",
     "examples",
 ]
-resolver = "2"
 
 [package.metadata.docs.rs]
 no-default-features = true

README.md

@@ -53,7 +53,7 @@ The most important files generated by this command are `Cargo.toml` and `lib.rs`
 [package]
 name = "string_sum"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 
 [lib]
 # The name of the native library. This is the name which will be used in Python to import the

examples/Cargo.toml

@@ -2,7 +2,7 @@
 name = "examples"
 version = "0.0.0"
 publish = false
-edition = "2018"
+edition = "2021"
 
 [dev-dependencies]
 pyo3 = { version = "0.19.0", path = "..", features = ["auto-initialize", "extension-module"] }

examples/decorator/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "decorator"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 
 [lib]
 name = "decorator"

examples/maturin-starter/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "maturin-starter"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 
 [lib]
 name = "maturin_starter"

examples/setuptools-rust-starter/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "setuptools-rust-starter"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 
 [lib]
 name = "setuptools_rust_starter"

examples/word-count/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "word-count"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 
 [lib]
 name = "word_count"

guide/src/class/numeric.md

@@ -71,7 +71,6 @@ impl Number {
 
 With that out of the way, let's implement some operators:
 ```rust
-use std::convert::TryInto;
 use pyo3::exceptions::{PyZeroDivisionError, PyValueError};
 
 # use pyo3::prelude::*;

pyo3-build-config/Cargo.toml

@@ -8,7 +8,7 @@ homepage = "https://github.com/pyo3/pyo3"
 repository = "https://github.com/pyo3/pyo3"
 categories = ["api-bindings", "development-tools::ffi"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 once_cell = "1"

pyo3-ffi-check/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "pyo3-ffi-check"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]

pyo3-ffi-check/macro/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "pyo3-ffi-check-macro"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [lib]

pyo3-ffi/Cargo.toml

@@ -8,7 +8,7 @@ homepage = "https://github.com/pyo3/pyo3"
 repository = "https://github.com/pyo3/pyo3"
 categories = ["api-bindings", "development-tools::ffi"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 links = "python"
 
 [dependencies]

pyo3-ffi/src/cpython/abstract_.rs

@@ -41,11 +41,11 @@ extern "C" {
     ) -> *mut PyObject;
 }
 
-#[cfg(all(Py_3_8))]
+#[cfg(Py_3_8)]
 const PY_VECTORCALL_ARGUMENTS_OFFSET: Py_ssize_t =
     1 << (8 * std::mem::size_of::<Py_ssize_t>() as Py_ssize_t - 1);
 
-#[cfg(all(Py_3_8))]
+#[cfg(Py_3_8)]
 #[inline(always)]
 pub unsafe fn PyVectorcall_NARGS(n: size_t) -> Py_ssize_t {
     assert!(n <= (PY_SSIZE_T_MAX as size_t));
@@ -113,7 +113,7 @@ extern "C" {
         kwnames: *mut PyObject,
     ) -> *mut PyObject;
 
-    #[cfg(all(Py_3_8))]
+    #[cfg(Py_3_8)]
     #[cfg_attr(all(not(PyPy), not(Py_3_9)), link_name = "_PyObject_VectorcallDict")]
     #[cfg_attr(all(PyPy, not(Py_3_9)), link_name = "_PyPyObject_VectorcallDict")]
     #[cfg_attr(all(PyPy, Py_3_9), link_name = "PyPyObject_VectorcallDict")]
@@ -124,7 +124,7 @@ extern "C" {
         kwdict: *mut PyObject,
     ) -> *mut PyObject;
 
-    #[cfg(all(Py_3_8))]
+    #[cfg(Py_3_8)]
     #[cfg_attr(not(any(Py_3_9, PyPy)), link_name = "_PyVectorcall_Call")]
     #[cfg_attr(PyPy, link_name = "PyPyVectorcall_Call")]
     pub fn PyVectorcall_Call(

pyo3-macros-backend/Cargo.toml

@@ -8,7 +8,7 @@ homepage = "https://github.com/pyo3/pyo3"
 repository = "https://github.com/pyo3/pyo3"
 categories = ["api-bindings", "development-tools::ffi"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 
 # Note: we use default-features = false for proc-macro related crates
 # not to depend on proc-macro itself.

pyo3-macros-backend/src/frompyobject.rs

@@ -416,7 +416,7 @@ impl ContainerOptions {
                         }
                         ContainerPyO3Attribute::ItemAll(kw) => {
                             ensure_spanned!(
-                                matches!(options.from_item_all, None),
+                                options.from_item_all.is_none(),
                                 kw.span() => "`from_item_all` may only be provided once"
                             );
                             options.from_item_all = Some(kw);
@@ -608,7 +608,7 @@ pub fn build_derive_from_pyobject(tokens: &DeriveInput) -> Result<TokenStream> {
             use #krate as _pyo3;
 
             #[automatically_derived]
-            impl#trait_generics _pyo3::FromPyObject<#lt_param> for #ident#generics #where_clause {
+            impl #trait_generics _pyo3::FromPyObject<#lt_param> for #ident #generics #where_clause {
                 fn extract(obj: &#lt_param _pyo3::PyAny) -> _pyo3::PyResult<Self>  {
                     #derives
                 }

pyo3-macros/Cargo.toml

@@ -8,7 +8,7 @@ homepage = "https://github.com/pyo3/pyo3"
 repository = "https://github.com/pyo3/pyo3"
 categories = ["api-bindings", "development-tools::ffi"]
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 
 [lib]
 proc-macro = true

pytests/Cargo.toml

@@ -3,7 +3,7 @@ authors = ["PyO3 Authors"]
 name = "pyo3-pytests"
 version = "0.1.0"
 description = "Python-based tests for PyO3"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]

pytests/src/pyclasses.rs

@@ -16,6 +16,7 @@ impl EmptyClass {
 
 /// This is for demonstrating how to return a value from __next__
 #[pyclass]
+#[derive(Default)]
 struct PyClassIter {
     count: usize,
 }
@@ -24,7 +25,7 @@ struct PyClassIter {
 impl PyClassIter {
     #[new]
     pub fn new() -> Self {
-        PyClassIter { count: 0 }
+        Default::default()
     }
 
     fn __next__(&mut self) -> IterNextOutput<usize, &'static str> {

src/lib.rs

@@ -139,7 +139,7 @@
 //! [package]
 //! name = "string-sum"
 //! version = "0.1.0"
-//! edition = "2018"
+//! edition = "2021"
 //!
 //! [lib]
 //! name = "string_sum"

src/pycell.rs

@@ -499,7 +499,6 @@ impl<T: PyClass> PyCell<T> {
     /// Gets the offset of the dictionary from the start of the struct in bytes.
     pub(crate) fn dict_offset() -> ffi::Py_ssize_t {
         use memoffset::offset_of;
-        use std::convert::TryInto;
 
         let offset = offset_of!(PyCell<T>, contents) + offset_of!(PyCellContents<T>, dict);
 
@@ -511,7 +510,6 @@ impl<T: PyClass> PyCell<T> {
     /// Gets the offset of the weakref list from the start of the struct in bytes.
     pub(crate) fn weaklist_offset() -> ffi::Py_ssize_t {
         use memoffset::offset_of;
-        use std::convert::TryInto;
 
         let offset = offset_of!(PyCell<T>, contents) + offset_of!(PyCellContents<T>, weakref);
 

src/test_hygiene/pyclass.rs

@@ -56,6 +56,6 @@ pub struct Foo4 {
     field: i32,
 
     #[pyo3(get, set)]
-    #[cfg(any(not(FALSE)))]
+    #[cfg(not(FALSE))]
     field: u32,
 }

tests/ui/invalid_closure.stderr

@@ -8,21 +8,3 @@ error[E0597]: `local_data` does not live long enough
    |         ---------------------------------------------------- argument requires that `local_data` is borrowed for `'static`
 14 |     });
    |     - `local_data` dropped here while still borrowed
-
-error[E0373]: closure may outlive the current function, but it borrows `ref_`, which is owned by the current function
-  --> tests/ui/invalid_closure.rs:9:26
-   |
-9  |         let closure_fn = |_args: &PyTuple, _kwargs: Option<&PyDict>| -> PyResult<()> {
-   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ may outlive borrowed value `ref_`
-10 |             println!("This is five: {:?}", ref_.len());
-   |                                            ---- `ref_` is borrowed here
-   |
-note: function requires argument type to outlive `'static`
-  --> tests/ui/invalid_closure.rs:13:9
-   |
-13 |         PyCFunction::new_closure(py, None, None, closure_fn).unwrap().into()
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-help: to force the closure to take ownership of `ref_` (and any other referenced variables), use the `move` keyword
-   |
-9  |         let closure_fn = move |_args: &PyTuple, _kwargs: Option<&PyDict>| -> PyResult<()> {
-   |                          ++++