perform PyLong check for 3.8 too

src/conversions/std/num.rs

@@ -50,11 +50,13 @@ macro_rules! extract_int {
     };
 
     ($obj:ident, $error_val:expr, $pylong_as:expr, $force_index_call: literal) => {
-        // with python 3.8+ PyLong_AsLong takes care of calling PyNumber_Index itself
+        // with python 3.9+ PyLong_AsLong takes care of calling PyNumber_Index itself
         // hence no need for the slow `PyNumber_Index` path
         // `PyLong_AsUnsignedLongLong` does not call `__index__`, hence the `force_index_call` argument
-        // see https://github.com/PyO3/pyo3/pull/3742 for detials.
-        if cfg!(Py_3_8) && !$force_index_call {
+        // 3.8 is a special case where `PyNumber_Index` is called but has slightly different semantics
+        // thus we use the conservative path for 3.8
+        // See https://github.com/PyO3/pyo3/pull/3742 for detials
+        if cfg!(Py_3_9) && !$force_index_call {
             err_if_invalid_value($obj.py(), $error_val, unsafe { $pylong_as($obj.as_ptr()) })
         } else if let Ok(long) = $obj.downcast::<crate::types::PyLong>() {
             // with 3.7 we have to do the `PyNumber_Index` check ourselves