From 378a6a484c385b7e848528fef97a6f8cf8a95016 Mon Sep 17 00:00:00 2001
From: Martin Larralde <martin.larralde@ens-paris-saclay.fr>
Date: Sun, 19 Apr 2020 12:57:31 +0200
Subject: [PATCH] Move `TryFromPyCell` trait to `derive_utils` module

---
 src/class/iter.rs   |  2 +-
 src/derive_utils.rs | 26 ++++++++++++++++++++++++--
 src/pycell.rs       | 21 ---------------------
 3 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/src/class/iter.rs b/src/class/iter.rs
index cf7cb405..08c12963 100644
--- a/src/class/iter.rs
+++ b/src/class/iter.rs
@@ -3,8 +3,8 @@
 //! Trait and support implementation for implementing iterators
 
 use crate::callback::IntoPyCallbackOutput;
+use crate::derive_utils::TryFromPyCell;
 use crate::err::PyResult;
-use crate::pycell::TryFromPyCell;
 use crate::{ffi, IntoPy, IntoPyPointer, PyClass, PyObject, Python};
 
 /// Python Iterator Interface.
diff --git a/src/derive_utils.rs b/src/derive_utils.rs
index ab180e87..e70d5842 100644
--- a/src/derive_utils.rs
+++ b/src/derive_utils.rs
@@ -4,13 +4,13 @@
 
 //! Functionality for the code generated by the derive backend
 
-use crate::err::PyResult;
+use crate::err::{PyErr, PyResult};
 use crate::exceptions::TypeError;
 use crate::instance::PyNativeType;
 use crate::pyclass::PyClass;
 use crate::pyclass_init::PyClassInitializer;
 use crate::types::{PyAny, PyDict, PyModule, PyTuple};
-use crate::{ffi, GILPool, IntoPy, PyObject, Python};
+use crate::{ffi, GILPool, IntoPy, PyCell, PyObject, Python};
 use std::cell::UnsafeCell;
 
 /// Description of a python parameter; used for `parse_args()`.
@@ -243,3 +243,25 @@ where
 {
     type Target = T;
 }
+
+/// A trait for types that can be borrowed from a cell.
+///
+/// This serves to unify the use of `PyRef` and `PyRefMut` in automatically
+/// derived code, since both types can be obtained from a `PyCell`.
+#[doc(hidden)]
+pub trait TryFromPyCell<'a, T: PyClass>: Sized {
+    type Error: Into<PyErr>;
+    fn try_from_pycell(cell: &'a crate::PyCell<T>) -> Result<Self, Self::Error>;
+}
+
+impl<'a, T, R> TryFromPyCell<'a, T> for R
+where
+    T: 'a + PyClass,
+    R: std::convert::TryFrom<&'a PyCell<T>>,
+    R::Error: Into<PyErr>,
+{
+    type Error = R::Error;
+    fn try_from_pycell(cell: &'a crate::PyCell<T>) -> Result<Self, Self::Error> {
+        <R as std::convert::TryFrom<&'a PyCell<T>>>::try_from(cell)
+    }
+}
diff --git a/src/pycell.rs b/src/pycell.rs
index b5ec6641..82dcf9ba 100644
--- a/src/pycell.rs
+++ b/src/pycell.rs
@@ -647,27 +647,6 @@ impl<T: PyClass + fmt::Debug> fmt::Debug for PyRefMut<'_, T> {
     }
 }
 
-/// A trait for types that can be borrowed from a cell.
-///
-/// This serves to unify the use of `PyRef` and `PyRefMut` in automatically
-/// derived code, since both types can be obtained from a `PyCell`.
-pub trait TryFromPyCell<'a, T: PyClass>: Sized {
-    type Error: Into<PyErr>;
-    fn try_from_pycell(cell: &'a crate::PyCell<T>) -> Result<Self, Self::Error>;
-}
-
-impl<'a, T, R> TryFromPyCell<'a, T> for R
-where
-    T: 'a + PyClass,
-    R: std::convert::TryFrom<&'a PyCell<T>>,
-    R::Error: Into<PyErr>,
-{
-    type Error = R::Error;
-    fn try_from_pycell(cell: &'a crate::PyCell<T>) -> Result<Self, Self::Error> {
-        <R as std::convert::TryFrom<&'a PyCell<T>>>::try_from(cell)
-    }
-}
-
 #[derive(Copy, Clone, Eq, PartialEq)]
 struct BorrowFlag(usize);