Split Proxied into Proxied and MutProxied traits.

Proxied is not marked as Sized yet, because ProtoStr is still dynamically sized. We will wait for clarity for the string types before marking Proxied Sized.

PiperOrigin-RevId: 627707544

rust/map.rs

@@ -6,7 +6,7 @@
 // https://developers.google.com/open-source/licenses/bsd
 
 use crate::{
-    Mut, MutProxy, Proxied, SettableValue, View, ViewProxy,
+    Mut, MutProxied, MutProxy, Proxied, SettableValue, View, ViewProxy,
     __internal::Private,
     __runtime::{InnerMap, InnerMapMut, RawMap, RawMapIter},
 };
@@ -95,6 +95,9 @@ where
 
 impl<K: Proxied + ?Sized, V: ProxiedInMapValue<K> + ?Sized> Proxied for Map<K, V> {
     type View<'msg> = MapView<'msg, K, V> where K: 'msg, V: 'msg;
+}
+
+impl<K: Proxied + ?Sized, V: ProxiedInMapValue<K> + ?Sized> MutProxied for Map<K, V> {
     type Mut<'msg> = MapMut<'msg, K, V> where K: 'msg, V: 'msg;
 }
 

rust/optional.rs

@@ -10,7 +10,9 @@
 #![allow(unused)]
 
 use crate::__internal::Private;
-use crate::{Mut, MutProxy, Proxied, ProxiedWithPresence, SettableValue, View, ViewProxy};
+use crate::{
+    Mut, MutProxied, MutProxy, Proxied, ProxiedWithPresence, SettableValue, View, ViewProxy,
+};
 use std::convert::{AsMut, AsRef};
 use std::fmt::{self, Debug};
 use std::panic;
@@ -495,6 +497,9 @@ mod tests {
 
     impl Proxied for VtableProxied {
         type View<'msg> = VtableProxiedView;
+    }
+
+    impl MutProxied for VtableProxied {
         type Mut<'msg> = VtableProxiedMut<'msg>;
     }
 

rust/primitive.rs

@@ -10,7 +10,9 @@ use std::fmt::Debug;
 use crate::__internal::Private;
 use crate::__runtime::InnerPrimitiveMut;
 use crate::vtable::{PrimitiveWithRawVTable, ProxiedWithRawVTable, RawVTableOptionalMutatorData};
-use crate::{Mut, MutProxy, Proxied, ProxiedWithPresence, SettableValue, View, ViewProxy};
+use crate::{
+    Mut, MutProxied, MutProxy, Proxied, ProxiedWithPresence, SettableValue, View, ViewProxy,
+};
 
 /// A mutator for a primitive (numeric or enum) value of `T`.
 ///
@@ -98,6 +100,9 @@ macro_rules! impl_singular_primitives {
       $(
         impl Proxied for $t {
             type View<'msg> = $t;
+        }
+
+        impl MutProxied for $t {
             type Mut<'msg> = PrimitiveMut<'msg, $t>;
         }
 

rust/proto_macro.rs

@@ -53,13 +53,13 @@ macro_rules! proto_internal {
     // nested message
     (@msg $msg:ident $submsg:ident : $($msgtype:ident)::+ { $field:ident : $($value:tt)* }) => {
         {
-            let mut $msg: <$($msgtype)::+ as $crate::Proxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
+            let mut $msg: <$($msgtype)::+ as $crate::MutProxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
             proto_internal!(@msg $msg $field : $($value)*);
         }
     };
     (@msg $msg:ident $submsg:ident : ::$($msgtype:ident)::+ { $field:ident : $($value:tt)* }) => {
         {
-            let mut $msg: <::$($msgtype)::+ as $crate::Proxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
+            let mut $msg: <::$($msgtype)::+ as $crate::MutProxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
             proto_internal!(@msg $msg $field : $($value)*);
         }
     };
@@ -77,12 +77,12 @@ macro_rules! proto_internal {
     // empty nested message
     (@msg $msg:ident $submsg:ident : $($msgtype:ident)::+ { }) => {
         {
-            let mut $msg: <$($msgtype)::+ as $crate::Proxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
+            let mut $msg: <$($msgtype)::+ as $crate::MutProxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
         }
     };
     (@msg $msg:ident $submsg:ident : ::$($msgtype:ident)::+ { }) => {
         {
-            let mut $msg: <::$($msgtype)::+ as $crate::Proxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
+            let mut $msg: <::$($msgtype)::+ as $crate::MutProxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
         }
     };
 

rust/proxied.rs

@@ -51,18 +51,25 @@ use std::fmt::Debug;
 
 /// A type that can be accessed through a reference-like proxy.
 ///
-/// An instance of a `Proxied` can be accessed
-/// immutably via `Proxied::View` and mutably via `Proxied::Mut`.
+/// An instance of a `Proxied` can be accessed immutably via `Proxied::View`.
 ///
 /// All Protobuf field types implement `Proxied`.
 pub trait Proxied {
     /// The proxy type that provides shared access to a `T`, like a `&'msg T`.
     ///
     /// Most code should use the type alias [`View`].
-    type View<'msg>: ViewProxy<'msg, Proxied = Self> + Copy + Send + SettableValue<Self>
+    type View<'msg>: ViewProxy<'msg, Proxied = Self> + Copy + Send
     where
         Self: 'msg;
+}
 
+/// A type that can be be accessed through a reference-like proxy.
+///
+/// An instance of a `MutProxied` can be accessed mutably via `MutProxied::Mut`
+/// and immutably via `MutProxied::View`.
+///
+/// `MutProxied` is implemented by message, map and repeated field types.
+pub trait MutProxied: Proxied {
     /// The proxy type that provides exclusive mutable access to a `T`, like a
     /// `&'msg mut T`.
     ///
@@ -83,7 +90,7 @@ pub type View<'msg, T> = <T as Proxied>::View<'msg>;
 ///
 /// This is more concise than fully spelling the associated type.
 #[allow(dead_code)]
-pub type Mut<'msg, T> = <T as Proxied>::Mut<'msg>;
+pub type Mut<'msg, T> = <T as MutProxied>::Mut<'msg>;
 
 /// Declares conversion operations common to all views.
 ///
@@ -147,7 +154,10 @@ pub trait ViewProxy<'msg>: 'msg + Sync + Unpin + Sized + Debug {
 ///
 /// This trait is intentionally made non-object-safe to prevent a potential
 /// future incompatible change.
-pub trait MutProxy<'msg>: ViewProxy<'msg> {
+pub trait MutProxy<'msg>: ViewProxy<'msg>
+where
+    Self::Proxied: MutProxied,
+{
     /// Gets an immutable view of this field. This is shorthand for `as_view`.
     ///
     /// This provides a shorter lifetime than `into_view` but can also be called
@@ -211,7 +221,7 @@ pub trait MutProxy<'msg>: ViewProxy<'msg> {
 ///
 /// All scalar and message types implement `ProxiedWithPresence`, while repeated
 /// types don't.
-pub trait ProxiedWithPresence: Proxied {
+pub trait ProxiedWithPresence: MutProxied {
     /// The data necessary to store a present field mutator proxying `Self`.
     /// This is the contents of `PresentField<'msg, Self>`.
     type PresentMutData<'msg>: MutProxy<'msg, Proxied = Self>;
@@ -233,7 +243,7 @@ pub trait ProxiedWithPresence: Proxied {
 /// Values that can be used to set a field of `T`.
 pub trait SettableValue<T>: Sized
 where
-    T: Proxied + ?Sized,
+    T: MutProxied + ?Sized,
 {
     /// Consumes `self` to set the given mutator to the value of `self`.
     #[doc(hidden)]
@@ -308,6 +318,9 @@ mod tests {
 
     impl Proxied for MyProxied {
         type View<'msg> = MyProxiedView<'msg>;
+    }
+
+    impl MutProxied for MyProxied {
         type Mut<'msg> = MyProxiedMut<'msg>;
     }
 
@@ -460,7 +473,7 @@ mod tests {
         y: &'b View<'a, T>,
     ) -> [View<'b, T>; 2]
     where
-        T: Proxied,
+        T: MutProxied,
         'a: 'b,
     {
         // `[x, y]` fails to compile because `'a` is not the same as `'b` and the `View`
@@ -509,7 +522,7 @@ mod tests {
 
     fn reborrow_generic_mut_into_view<'a, 'b, T>(x: Mut<'a, T>, y: View<'b, T>) -> [View<'b, T>; 2]
     where
-        T: Proxied,
+        T: MutProxied,
         'a: 'b,
     {
         [x.into_view(), y]
@@ -529,7 +542,7 @@ mod tests {
 
     fn reborrow_generic_mut_into_mut<'a, 'b, T>(x: Mut<'a, T>, y: Mut<'b, T>) -> [Mut<'b, T>; 2]
     where
-        T: Proxied,
+        T: MutProxied,
         'a: 'b,
     {
         // `[x, y]` fails to compile because `'a` is not the same as `'b` and the `Mut`

rust/repeated.rs

@@ -15,7 +15,7 @@ use std::iter::FusedIterator;
 use std::marker::PhantomData;
 
 use crate::{
-    Mut, MutProxy, Proxied, SettableValue, View, ViewProxy,
+    Mut, MutProxied, MutProxy, Proxied, SettableValue, View, ViewProxy,
     __internal::Private,
     __runtime::{InnerRepeated, InnerRepeatedMut, RawRepeatedField},
 };
@@ -314,6 +314,12 @@ where
     T: ProxiedInRepeated + ?Sized,
 {
     type View<'msg> = RepeatedView<'msg, T> where Repeated<T>: 'msg;
+}
+
+impl<T> MutProxied for Repeated<T>
+where
+    T: ProxiedInRepeated + ?Sized,
+{
     type Mut<'msg> = RepeatedMut<'msg, T> where Repeated<T>: 'msg;
 }
 

rust/shared.rs

@@ -28,7 +28,7 @@ pub mod __public {
     pub use crate::primitive::PrimitiveMut;
     pub use crate::proto;
     pub use crate::proxied::{
-        Mut, MutProxy, Proxied, ProxiedWithPresence, SettableValue, View, ViewProxy,
+        Mut, MutProxied, MutProxy, Proxied, ProxiedWithPresence, SettableValue, View, ViewProxy,
     };
     pub use crate::repeated::{
         ProxiedInRepeated, Repeated, RepeatedIter, RepeatedMut, RepeatedView,

rust/string.rs

@@ -15,8 +15,8 @@ use crate::__runtime::{
 };
 use crate::macros::impl_forwarding_settable_value;
 use crate::{
-    AbsentField, FieldEntry, Mut, MutProxy, Optional, PresentField, Proxied, ProxiedWithPresence,
-    SettableValue, View, ViewProxy,
+    AbsentField, FieldEntry, Mut, MutProxied, MutProxy, Optional, PresentField, Proxied,
+    ProxiedWithPresence, SettableValue, View, ViewProxy,
 };
 use std::borrow::Cow;
 use std::cmp::{Eq, Ord, Ordering, PartialEq, PartialOrd};
@@ -123,6 +123,9 @@ impl AsRef<[u8]> for BytesMut<'_> {
 
 impl Proxied for [u8] {
     type View<'msg> = &'msg [u8];
+}
+
+impl MutProxied for [u8] {
     type Mut<'msg> = BytesMut<'msg>;
 }
 
@@ -465,6 +468,9 @@ impl Ord for ProtoStr {
 
 impl Proxied for ProtoStr {
     type View<'msg> = &'msg ProtoStr;
+}
+
+impl MutProxied for ProtoStr {
     type Mut<'msg> = ProtoStrMut<'msg>;
 }
 

rust/vtable.rs

@@ -11,7 +11,7 @@ use crate::__runtime::{
     RawMessage,
 };
 use crate::{
-    AbsentField, FieldEntry, Mut, MutProxy, Optional, PresentField, PrimitiveMut, Proxied,
+    AbsentField, FieldEntry, Mut, MutProxied, MutProxy, Optional, PresentField, PrimitiveMut,
     ProxiedWithPresence, View, ViewProxy,
 };
 use std::fmt::{self, Debug};
@@ -23,7 +23,7 @@ use std::ptr::NonNull;
 ///
 /// This vtable should consist of `unsafe fn`s that call thunks that operate on
 /// `RawMessage`. The structure of this vtable is different per proxied type.
-pub trait ProxiedWithRawVTable: Proxied {
+pub trait ProxiedWithRawVTable: MutProxied {
     /// The vtable for get/set access, stored in static memory.
     type VTable: Debug + 'static;
 
@@ -443,7 +443,7 @@ pub trait PrimitiveWithRawVTable:
     + ProxiedWithPresence
     + Sync
     + Send
-    + for<'msg> Proxied<View<'msg> = Self, Mut<'msg> = PrimitiveMut<'msg, Self>>
+    + for<'msg> MutProxied<View<'msg> = Self, Mut<'msg> = PrimitiveMut<'msg, Self>>
 {
 }
 

src/google/protobuf/compiler/rust/enum.cc

@@ -393,6 +393,9 @@ void GenerateEnumDefinition(Context& ctx, const EnumDescriptor& desc) {
 
       impl $pb$::Proxied for $name$ {
         type View<'a> = $name$;
+      }
+
+      impl $pb$::MutProxied for $name$ {
         type Mut<'a> = $pb$::PrimitiveMut<'a, $name$>;
       }
 

src/google/protobuf/compiler/rust/message.cc

@@ -865,6 +865,9 @@ void GenerateRs(Context& ctx, const Descriptor& msg) {
 
         impl $pb$::Proxied for $Msg$ {
           type View<'msg> = $Msg$View<'msg>;
+        }
+
+        impl $pb$::MutProxied for $Msg$ {
           type Mut<'msg> = $Msg$Mut<'msg>;
         }