prevent manual __hash__ with #pyo3(hash)

Author: Icxolu

pyo3-macros-backend/src/pyclass.rs

@@ -1813,14 +1813,14 @@ fn pyclass_hash(
     match options.hash {
         Some(opt) => {
             let mut hash_impl = parse_quote_spanned! { opt.span() =>
-                fn __pyo3__hash__(&self) -> u64 {
+                fn __pyo3__generated____hash__(&self) -> u64 {
                     let mut s = ::std::collections::hash_map::DefaultHasher::new();
                     ::std::hash::Hash::hash(self, &mut s);
                     ::std::hash::Hasher::finish(&s)
                 }
             };
             let hash_slot =
-                generate_default_protocol_slot(cls, &mut hash_impl, &__HASH__, ctx).unwrap();
+                generate_protocol_slot(cls, &mut hash_impl, &__HASH__, "__hash__", ctx).unwrap();
             Ok((Some(hash_impl), Some(hash_slot)))
         }
         None => Ok((None, None)),

tests/ui/invalid_pyclass_args.rs

@@ -64,4 +64,15 @@ struct HashWithoutFrozen;
 #[derive(Hash)]
 struct HashWithoutEq;
 
+#[pyclass(frozen, eq, hash)]
+#[derive(PartialEq, Hash)]
+struct HashOptAndManualHash {}
+
+#[pymethods]
+impl HashOptAndManualHash {
+    fn __hash__(&self) -> u64 {
+        todo!()
+    }
+}
+
 fn main() {}

tests/ui/invalid_pyclass_args.stderr

@@ -87,6 +87,17 @@ error[E0592]: duplicate definitions with name `__pymethod___richcmp____`
    |
    = note: this error originates in the attribute macro `pyclass` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+error[E0592]: duplicate definitions with name `__pymethod___hash____`
+  --> tests/ui/invalid_pyclass_args.rs:67:1
+   |
+67 | #[pyclass(frozen, eq, hash)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ duplicate definitions for `__pymethod___hash____`
+...
+71 | #[pymethods]
+   | ------------ other definition for `__pymethod___hash____`
+   |
+   = note: this error originates in the attribute macro `pyclass` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error[E0369]: binary operation `==` cannot be applied to type `&EqOptRequiresEq`
   --> tests/ui/invalid_pyclass_args.rs:33:11
    |
@@ -168,3 +179,39 @@ help: consider annotating `HashOptRequiresHash` with `#[derive(Hash)]`
 57 + #[derive(Hash)]
 58 | struct HashOptRequiresHash;
    |
+
+error[E0034]: multiple applicable items in scope
+  --> tests/ui/invalid_pyclass_args.rs:67:1
+   |
+67 | #[pyclass(frozen, eq, hash)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ multiple `__pymethod___hash____` found
+   |
+note: candidate #1 is defined in an impl for the type `HashOptAndManualHash`
+  --> tests/ui/invalid_pyclass_args.rs:67:1
+   |
+67 | #[pyclass(frozen, eq, hash)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+note: candidate #2 is defined in an impl for the type `HashOptAndManualHash`
+  --> tests/ui/invalid_pyclass_args.rs:71:1
+   |
+71 | #[pymethods]
+   | ^^^^^^^^^^^^
+   = note: this error originates in the attribute macro `pyclass` which comes from the expansion of the attribute macro `pymethods` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0034]: multiple applicable items in scope
+  --> tests/ui/invalid_pyclass_args.rs:71:1
+   |
+71 | #[pymethods]
+   | ^^^^^^^^^^^^ multiple `__pymethod___hash____` found
+   |
+note: candidate #1 is defined in an impl for the type `HashOptAndManualHash`
+  --> tests/ui/invalid_pyclass_args.rs:67:1
+   |
+67 | #[pyclass(frozen, eq, hash)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+note: candidate #2 is defined in an impl for the type `HashOptAndManualHash`
+  --> tests/ui/invalid_pyclass_args.rs:71:1
+   |
+71 | #[pymethods]
+   | ^^^^^^^^^^^^
+   = note: this error originates in the attribute macro `pymethods` (in Nightly builds, run with -Z macro-backtrace for more info)