fix __clear__ slot naming collision with clear method (#4619)

* fix `__clear__` slot naming collision with `clear` method

* add newsfragment

newsfragments/4619.fixed.md

@@ -0,0 +1 @@
+fixed `__clear__` slot naming collision with `clear` method

pyo3-macros-backend/src/pymethod.rs

@@ -509,20 +509,20 @@ fn impl_clear_slot(cls: &syn::Type, spec: &FnSpec<'_>, ctx: &Ctx) -> syn::Result
     };
 
     let associated_method = quote! {
-        pub unsafe extern "C" fn __pymethod_clear__(
+        pub unsafe extern "C" fn __pymethod___clear____(
             _slf: *mut #pyo3_path::ffi::PyObject,
         ) -> ::std::os::raw::c_int {
             #pyo3_path::impl_::pymethods::_call_clear(_slf, |py, _slf| {
                 #holders
                 let result = #fncall;
                 #pyo3_path::callback::convert(py, result)
-            }, #cls::__pymethod_clear__)
+            }, #cls::__pymethod___clear____)
         }
     };
     let slot_def = quote! {
         #pyo3_path::ffi::PyType_Slot {
             slot: #pyo3_path::ffi::Py_tp_clear,
-            pfunc: #cls::__pymethod_clear__ as #pyo3_path::ffi::inquiry as _
+            pfunc: #cls::__pymethod___clear____ as #pyo3_path::ffi::inquiry as _
         }
     };
     Ok(MethodAndSlotDef {

src/tests/hygiene/pymethods.rs

@@ -412,6 +412,24 @@ impl Dummy {
     // Buffer protocol?
 }
 
+#[crate::pyclass(crate = "crate")]
+struct Clear;
+
+#[crate::pymethods(crate = "crate")]
+impl Clear {
+    pub fn __traverse__(
+        &self,
+        visit: crate::PyVisit<'_>,
+    ) -> ::std::result::Result<(), crate::PyTraverseError> {
+        ::std::result::Result::Ok(())
+    }
+
+    pub fn __clear__(&self) {}
+
+    #[pyo3(signature=(*, reuse=false))]
+    pub fn clear(&self, reuse: bool) {}
+}
+
 // Ensure that crate argument is also accepted inline
 
 #[crate::pyclass(crate = "crate")]