Fix broken specialized implementations with Rust 1.40

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Fixed
 
  * Make sure the right Python interpreter is used in OSX builds. [#604](https://github.com/PyO3/pyo3/pull/604)
+ * Patch specialization being broken by Rust 1.40 [#614](https://github.com/PyO3/pyo3/issues/614)
 
 ## [0.8.0] - 2018-09-05
 

pyo3-derive-backend/src/pymethod.rs

@@ -38,7 +38,7 @@ pub fn gen_py_method(
                     return Err(syn::Error::new_spanned(
                         spec.args[0].ty,
                         "Getter function can only have one argument of type pyo3::Python!",
-                    ))
+                    ));
                 }
             };
             impl_py_getter_def(name, doc, getter, &impl_wrap_getter(cls, name, takes_py))
@@ -60,10 +60,10 @@ fn check_generic(name: &syn::Ident, sig: &syn::Signature) -> syn::Result<()> {
         match param {
             syn::GenericParam::Lifetime(_) => {}
             syn::GenericParam::Type(_) => {
-                return Err(syn::Error::new_spanned(param, err_msg("type")))
+                return Err(syn::Error::new_spanned(param, err_msg("type")));
             }
             syn::GenericParam::Const(_) => {
-                return Err(syn::Error::new_spanned(param, err_msg("const")))
+                return Err(syn::Error::new_spanned(param, err_msg("const")));
             }
         }
     }

src/class/basic.rs

@@ -152,17 +152,21 @@ pub trait PyObjectRichcmpProtocol<'p>: PyObjectProtocol<'p> {
 
 #[doc(hidden)]
 pub trait PyObjectProtocolImpl {
-    fn methods() -> Vec<PyMethodDef> {
+    fn methods() -> Vec<PyMethodDef>;
+    fn tp_as_object(_type_object: &mut ffi::PyTypeObject);
+    fn nb_bool_fn() -> Option<ffi::inquiry>;
+}
+
+impl<T> PyObjectProtocolImpl for T {
+    default fn methods() -> Vec<PyMethodDef> {
         Vec::new()
     }
-    fn tp_as_object(_type_object: &mut ffi::PyTypeObject) {}
-    fn nb_bool_fn() -> Option<ffi::inquiry> {
+    default fn tp_as_object(_type_object: &mut ffi::PyTypeObject) {}
+    default fn nb_bool_fn() -> Option<ffi::inquiry> {
         None
     }
 }
 
-impl<T> PyObjectProtocolImpl for T {}
-
 impl<'p, T> PyObjectProtocolImpl for T
 where
     T: PyObjectProtocol<'p>,
@@ -195,13 +199,18 @@ where
 }
 
 trait GetAttrProtocolImpl {
-    fn tp_getattro() -> Option<ffi::binaryfunc> {
+    fn tp_getattro() -> Option<ffi::binaryfunc>;
+}
+
+impl<'p, T> GetAttrProtocolImpl for T
+where
+    T: PyObjectProtocol<'p>,
+{
+    default fn tp_getattro() -> Option<ffi::binaryfunc> {
         None
     }
 }
 
-impl<'p, T> GetAttrProtocolImpl for T where T: PyObjectProtocol<'p> {}
-
 impl<T> GetAttrProtocolImpl for T
 where
     T: for<'p> PyObjectGetAttrProtocol<'p>,
@@ -268,13 +277,15 @@ mod tp_setattro_impl {
     }
 
     trait SetAttr {
-        fn set_attr() -> Option<ffi::setattrofunc> {
+        fn set_attr() -> Option<ffi::setattrofunc>;
+    }
+
+    impl<'p, T: PyObjectProtocol<'p>> SetAttr for T {
+        default fn set_attr() -> Option<ffi::setattrofunc> {
             None
         }
     }
 
-    impl<'p, T: PyObjectProtocol<'p>> SetAttr for T {}
-
     impl<T> SetAttr for T
     where
         T: for<'p> PyObjectSetAttrProtocol<'p>,
@@ -285,13 +296,18 @@ mod tp_setattro_impl {
     }
 
     trait DelAttr {
-        fn del_attr() -> Option<ffi::setattrofunc> {
+        fn del_attr() -> Option<ffi::setattrofunc>;
+    }
+
+    impl<'p, T> DelAttr for T
+    where
+        T: PyObjectProtocol<'p>,
+    {
+        default fn del_attr() -> Option<ffi::setattrofunc> {
             None
         }
     }
 
-    impl<'p, T> DelAttr for T where T: PyObjectProtocol<'p> {}
-
     impl<T> DelAttr for T
     where
         T: for<'p> PyObjectDelAttrProtocol<'p>,
@@ -302,13 +318,18 @@ mod tp_setattro_impl {
     }
 
     trait SetDelAttr {
-        fn set_del_attr() -> Option<ffi::setattrofunc> {
+        fn set_del_attr() -> Option<ffi::setattrofunc>;
+    }
+
+    impl<'p, T> SetDelAttr for T
+    where
+        T: PyObjectProtocol<'p>,
+    {
+        default fn set_del_attr() -> Option<ffi::setattrofunc> {
             None
         }
     }
 
-    impl<'p, T> SetDelAttr for T where T: PyObjectProtocol<'p> {}
-
     impl<T> SetDelAttr for T
     where
         T: for<'p> PyObjectSetAttrProtocol<'p> + for<'p> PyObjectDelAttrProtocol<'p>,
@@ -326,11 +347,16 @@ mod tp_setattro_impl {
 }
 
 trait StrProtocolImpl {
-    fn tp_str() -> Option<ffi::unaryfunc> {
+    fn tp_str() -> Option<ffi::unaryfunc>;
+}
+impl<'p, T> StrProtocolImpl for T
+where
+    T: PyObjectProtocol<'p>,
+{
+    default fn tp_str() -> Option<ffi::unaryfunc> {
         None
     }
 }
-impl<'p, T> StrProtocolImpl for T where T: PyObjectProtocol<'p> {}
 impl<T> StrProtocolImpl for T
 where
     T: for<'p> PyObjectStrProtocol<'p>,
@@ -346,11 +372,16 @@ where
 }
 
 trait ReprProtocolImpl {
-    fn tp_repr() -> Option<ffi::unaryfunc> {
+    fn tp_repr() -> Option<ffi::unaryfunc>;
+}
+impl<'p, T> ReprProtocolImpl for T
+where
+    T: PyObjectProtocol<'p>,
+{
+    default fn tp_repr() -> Option<ffi::unaryfunc> {
         None
     }
 }
-impl<'p, T> ReprProtocolImpl for T where T: PyObjectProtocol<'p> {}
 impl<T> ReprProtocolImpl for T
 where
     T: for<'p> PyObjectReprProtocol<'p>,
@@ -367,34 +398,54 @@ where
 
 #[doc(hidden)]
 pub trait FormatProtocolImpl {
-    fn __format__() -> Option<PyMethodDef> {
+    fn __format__() -> Option<PyMethodDef>;
+}
+impl<'p, T> FormatProtocolImpl for T
+where
+    T: PyObjectProtocol<'p>,
+{
+    default fn __format__() -> Option<PyMethodDef> {
         None
     }
 }
-impl<'p, T> FormatProtocolImpl for T where T: PyObjectProtocol<'p> {}
 
 #[doc(hidden)]
 pub trait BytesProtocolImpl {
-    fn __bytes__() -> Option<PyMethodDef> {
+    fn __bytes__() -> Option<PyMethodDef>;
+}
+impl<'p, T> BytesProtocolImpl for T
+where
+    T: PyObjectProtocol<'p>,
+{
+    default fn __bytes__() -> Option<PyMethodDef> {
         None
     }
 }
-impl<'p, T> BytesProtocolImpl for T where T: PyObjectProtocol<'p> {}
 
 #[doc(hidden)]
 pub trait UnicodeProtocolImpl {
-    fn __unicode__() -> Option<PyMethodDef> {
+    fn __unicode__() -> Option<PyMethodDef>;
+}
+impl<'p, T> UnicodeProtocolImpl for T
+where
+    T: PyObjectProtocol<'p>,
+{
+    default fn __unicode__() -> Option<PyMethodDef> {
         None
     }
 }
-impl<'p, T> UnicodeProtocolImpl for T where T: PyObjectProtocol<'p> {}
 
 trait HashProtocolImpl {
-    fn tp_hash() -> Option<ffi::hashfunc> {
+    fn tp_hash() -> Option<ffi::hashfunc>;
+}
+impl<'p, T> HashProtocolImpl for T
+where
+    T: PyObjectProtocol<'p>,
+{
+    default fn tp_hash() -> Option<ffi::hashfunc> {
         None
     }
 }
-impl<'p, T> HashProtocolImpl for T where T: PyObjectProtocol<'p> {}
 impl<T> HashProtocolImpl for T
 where
     T: for<'p> PyObjectHashProtocol<'p>,
@@ -411,11 +462,16 @@ where
 }
 
 trait BoolProtocolImpl {
-    fn nb_bool() -> Option<ffi::inquiry> {
+    fn nb_bool() -> Option<ffi::inquiry>;
+}
+impl<'p, T> BoolProtocolImpl for T
+where
+    T: PyObjectProtocol<'p>,
+{
+    default fn nb_bool() -> Option<ffi::inquiry> {
         None
     }
 }
-impl<'p, T> BoolProtocolImpl for T where T: PyObjectProtocol<'p> {}
 impl<T> BoolProtocolImpl for T
 where
     T: for<'p> PyObjectBoolProtocol<'p>,
@@ -432,11 +488,16 @@ where
 }
 
 trait RichcmpProtocolImpl {
-    fn tp_richcompare() -> Option<ffi::richcmpfunc> {
+    fn tp_richcompare() -> Option<ffi::richcmpfunc>;
+}
+impl<'p, T> RichcmpProtocolImpl for T
+where
+    T: PyObjectProtocol<'p>,
+{
+    default fn tp_richcompare() -> Option<ffi::richcmpfunc> {
         None
     }
 }
-impl<'p, T> RichcmpProtocolImpl for T where T: PyObjectProtocol<'p> {}
 impl<T> RichcmpProtocolImpl for T
 where
     T: for<'p> PyObjectRichcmpProtocol<'p>,

src/class/buffer.rs

@@ -41,13 +41,15 @@ pub trait PyBufferReleaseBufferProtocol<'p>: PyBufferProtocol<'p> {
 
 #[doc(hidden)]
 pub trait PyBufferProtocolImpl {
-    fn tp_as_buffer() -> Option<ffi::PyBufferProcs> {
+    fn tp_as_buffer() -> Option<ffi::PyBufferProcs>;
+}
+
+impl<T> PyBufferProtocolImpl for T {
+    default fn tp_as_buffer() -> Option<ffi::PyBufferProcs> {
         None
     }
 }
 
-impl<T> PyBufferProtocolImpl for T {}
-
 impl<'p, T> PyBufferProtocolImpl for T
 where
     T: PyBufferProtocol<'p>,
@@ -64,13 +66,18 @@ where
 }
 
 trait PyBufferGetBufferProtocolImpl {
-    fn cb_bf_getbuffer() -> Option<ffi::getbufferproc> {
+    fn cb_bf_getbuffer() -> Option<ffi::getbufferproc>;
+}
+
+impl<'p, T> PyBufferGetBufferProtocolImpl for T
+where
+    T: PyBufferProtocol<'p>,
+{
+    default fn cb_bf_getbuffer() -> Option<ffi::getbufferproc> {
         None
     }
 }
 
-impl<'p, T> PyBufferGetBufferProtocolImpl for T where T: PyBufferProtocol<'p> {}
-
 impl<T> PyBufferGetBufferProtocolImpl for T
 where
     T: for<'p> PyBufferGetBufferProtocol<'p>,

src/class/context.rs

@@ -47,13 +47,15 @@ pub trait PyContextExitProtocol<'p>: PyContextProtocol<'p> {
 
 #[doc(hidden)]
 pub trait PyContextProtocolImpl {
-    fn methods() -> Vec<PyMethodDef> {
+    fn methods() -> Vec<PyMethodDef>;
+}
+
+impl<T> PyContextProtocolImpl for T {
+    default fn methods() -> Vec<PyMethodDef> {
         Vec::new()
     }
 }
 
-impl<T> PyContextProtocolImpl for T {}
-
 impl<'p, T> PyContextProtocolImpl for T
 where
     T: PyContextProtocol<'p>,
@@ -75,18 +77,28 @@ where
 
 #[doc(hidden)]
 pub trait PyContextEnterProtocolImpl {
-    fn __enter__() -> Option<PyMethodDef> {
+    fn __enter__() -> Option<PyMethodDef>;
+}
+
+impl<'p, T> PyContextEnterProtocolImpl for T
+where
+    T: PyContextProtocol<'p>,
+{
+    default fn __enter__() -> Option<PyMethodDef> {
         None
     }
 }
 
-impl<'p, T> PyContextEnterProtocolImpl for T where T: PyContextProtocol<'p> {}
-
 #[doc(hidden)]
 pub trait PyContextExitProtocolImpl {
-    fn __exit__() -> Option<PyMethodDef> {
+    fn __exit__() -> Option<PyMethodDef>;
+}
+
+impl<'p, T> PyContextExitProtocolImpl for T
+where
+    T: PyContextProtocol<'p>,
+{
+    default fn __exit__() -> Option<PyMethodDef> {
         None
     }
 }
-
-impl<'p, T> PyContextExitProtocolImpl for T where T: PyContextProtocol<'p> {}