diff --git a/pyo3-macros-backend/src/pymethod.rs b/pyo3-macros-backend/src/pymethod.rs
index afdfd13a1f5..560c3c9dcc1 100644
--- a/pyo3-macros-backend/src/pymethod.rs
+++ b/pyo3-macros-backend/src/pymethod.rs
@@ -1349,7 +1349,10 @@ impl SlotDef {
         let name = spec.name;
         let holders = holders.init_holders(ctx);
         let dep = if method_name == "__richcmp__" {
-            quote! { impl #pyo3_path::impl_::pyclass::HasCustomRichCmp for #cls {} }
+            quote! {
+                #[allow(unknown_lints, non_local_definitions)]
+                impl #pyo3_path::impl_::pyclass::HasCustomRichCmp for #cls {}
+            }
         } else {
             TokenStream::default()
         };
diff --git a/tests/ui/invalid_proto_pymethods.stderr b/tests/ui/invalid_proto_pymethods.stderr
index 82c99c2ddc3..18c96113299 100644
--- a/tests/ui/invalid_proto_pymethods.stderr
+++ b/tests/ui/invalid_proto_pymethods.stderr
@@ -40,6 +40,17 @@ note: candidate #2 is defined in an impl for the type `EqAndRichcmp`
    | ^^^^^^^^^^^^
    = note: this error originates in the macro `::pyo3::impl_::pyclass::generate_pyclass_richcompare_slot` which comes from the expansion of the attribute macro `pymethods` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+error[E0119]: conflicting implementations of trait `HasCustomRichCmp` for type `EqAndRichcmp`
+  --> tests/ui/invalid_proto_pymethods.rs:55:1
+   |
+55 | #[pymethods]
+   | ^^^^^^^^^^^^
+   | |
+   | first implementation here
+   | conflicting implementation for `EqAndRichcmp`
+   |
+   = note: this error originates in the macro `::pyo3::impl_::pyclass::generate_pyclass_richcompare_slot` which comes from the expansion of the attribute macro `pymethods` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error[E0592]: duplicate definitions with name `__pymethod___richcmp____`
   --> tests/ui/invalid_proto_pymethods.rs:55:1
    |
diff --git a/tests/ui/invalid_pyclass_args.stderr b/tests/ui/invalid_pyclass_args.stderr
index 15aa0387cc6..d1335e0f1a1 100644
--- a/tests/ui/invalid_pyclass_args.stderr
+++ b/tests/ui/invalid_pyclass_args.stderr
@@ -162,6 +162,17 @@ error: The format string syntax cannot be used with enums
 171 | #[pyclass(eq, str = "Stuff...")]
     |                     ^^^^^^^^^^
 
+error[E0119]: conflicting implementations of trait `HasCustomRichCmp` for type `EqOptAndManualRichCmp`
+  --> tests/ui/invalid_pyclass_args.rs:41:1
+   |
+37 | #[pyclass(eq)]
+   | -------------- first implementation here
+...
+41 | #[pymethods]
+   | ^^^^^^^^^^^^ conflicting implementation for `EqOptAndManualRichCmp`
+   |
+   = note: this error originates in the attribute macro `pymethods` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error[E0592]: duplicate definitions with name `__pymethod___richcmp____`
   --> tests/ui/invalid_pyclass_args.rs:37:1
    |