Add ToPyErr::to_py_err

src/err/mod.rs

@@ -988,15 +988,18 @@ impl PyErrArguments for PyDowncastErrorArguments {
 ///
 /// Users should not need to implement this trait directly. It is implemented automatically in the
 /// [`crate::import_exception!`] and [`crate::create_exception!`] macros.
-pub trait ToPyErr {}
+pub trait ToPyErr {
+    /// Convert self to PyErr
+    fn to_py_err(self) -> PyErr;
+}
 
 impl<'py, T> std::convert::From<Bound<'py, T>> for PyErr
 where
-    T: ToPyErr,
+    Bound<'py, T>: ToPyErr,
 {
     #[inline]
     fn from(err: Bound<'py, T>) -> PyErr {
-        PyErr::from_value_bound(err.into_any())
+        err.to_py_err()
     }
 }
 

src/exceptions.rs

@@ -53,7 +53,11 @@ macro_rules! impl_exception_boilerplate {
             }
         }
 
-        impl $crate::ToPyErr for $name {}
+        impl $crate::ToPyErr for $crate::Bound<'_, $name> {
+            fn to_py_err(self) -> $crate::PyErr {
+                $crate::PyErr::from_value_bound(self.into_any())
+            }
+        }
     };
 }