rust: pin-init: internal: make `make_closure` inherent methods

The `InitData` and `PinData` traits do not need to exist, the inference
helpers could be inherent methods instead.

There is no risk for calling the wrong methods even when user defines it,
as inherent methods take priority over trait methods.

With this change, it unlocks the possibility of attaching additional bounds
to the method per type, which is not possible for trait methods.

Signed-off-by: Gary Guo <gary@garyguo.net>

diff --git a/rust/pin-init/internal/src/init.rs b/rust/pin-init/internal/src/init.rs
index a0b3c3790d43de8460cd6e053e20807ef7cb4a00..11affa76d1fc1e8a45e37a68ef47b20dd2fea717 100644 (file)
--- a/rust/pin-init/internal/src/init.rs
+++ b/rust/pin-init/internal/src/init.rs
@@ -103,17 +103,15 @@ pub(crate) fn expand(
         |(_, err)| Box::new(err),
     );
     let slot = format_ident!("slot");
-    let (has_data_trait, data_trait, get_data, init_from_closure) = if pinned {
+    let (has_data_trait, get_data, init_from_closure) = if pinned {
         (
             format_ident!("HasPinData"),
-            format_ident!("PinData"),
             format_ident!("__pin_data"),
             format_ident!("pin_init_from_closure"),
         )
     } else {
         (
             format_ident!("HasInitData"),
-            format_ident!("InitData"),
             format_ident!("__init_data"),
             format_ident!("init_from_closure"),
         )
@@ -157,8 +155,7 @@ pub(crate) fn expand(
             #path::#get_data()
         };
         // Ensure that `#data` really is of type `#data` and help with type inference:
-        let init = ::pin_init::__internal::#data_trait::make_closure::<_, #error>(
-            #data,
+        let init = #data.__make_closure::<_, #error>(
             move |slot| {
                 #zeroable_check
                 #this

diff --git a/rust/pin-init/internal/src/pin_data.rs b/rust/pin-init/internal/src/pin_data.rs
index 90f6b05b957ce1ded66b30348f214d2ff182aa98..713a43c2782674610fdd8cde8d53bb3d4122e2a4 100644 (file)
--- a/rust/pin-init/internal/src/pin_data.rs
+++ b/rust/pin-init/internal/src/pin_data.rs
@@ -447,6 +447,16 @@ fn generate_the_pin_data(
         impl #impl_generics __ThePinData #ty_generics
             #whr
         {
+            /// Type inference helper function.
+            #[inline(always)]
+            #vis fn __make_closure<__F, __E>(self, f: __F) -> __F
+            where
+                __F: FnOnce(*mut #struct_name #ty_generics) ->
+                    ::core::result::Result<::pin_init::__internal::InitOk, __E>,
+            {
+                f
+            }
+
             #field_accessors
         }
 
@@ -461,13 +471,6 @@ fn generate_the_pin_data(
                 __ThePinData { __phantom: ::pin_init::__internal::PhantomInvariant::new() }
             }
         }
-
-        // SAFETY: TODO
-        unsafe impl #impl_generics ::pin_init::__internal::PinData for __ThePinData #ty_generics
-            #whr
-        {
-            type Datee = #struct_name #ty_generics;
-        }
     }
 }
 

diff --git a/rust/pin-init/src/__internal.rs b/rust/pin-init/src/__internal.rs
index 010e8bfc6cd32a8d5c71a6e4e8da8e600f6dab14..d7fdcfef41d2becc7323e3312b133d96b9118cad 100644 (file)
--- a/rust/pin-init/src/__internal.rs
+++ b/rust/pin-init/src/__internal.rs
@@ -113,30 +113,12 @@ impl InitOk {
 ///
 /// Only the `init` module is allowed to use this trait.
 pub unsafe trait HasPinData {
-    type PinData: PinData;
+    type PinData;
 
     #[expect(clippy::missing_safety_doc)]
     unsafe fn __pin_data() -> Self::PinData;
 }
 
-/// Marker trait for pinning data of structs.
-///
-/// # Safety
-///
-/// Only the `init` module is allowed to use this trait.
-pub unsafe trait PinData: Copy {
-    type Datee: ?Sized + HasPinData;
-
-    /// Type inference helper function.
-    #[inline(always)]
-    fn make_closure<F, E>(self, f: F) -> F
-    where
-        F: FnOnce(*mut Self::Datee) -> Result<InitOk, E>,
-    {
-        f
-    }
-}
-
 /// This trait is automatically implemented for every type. It aims to provide the same type
 /// inference help as `HasPinData`.
 ///
@@ -144,30 +126,12 @@ pub unsafe trait PinData: Copy {
 ///
 /// Only the `init` module is allowed to use this trait.
 pub unsafe trait HasInitData {
-    type InitData: InitData;
+    type InitData;
 
     #[expect(clippy::missing_safety_doc)]
     unsafe fn __init_data() -> Self::InitData;
 }
 
-/// Same function as `PinData`, but for arbitrary data.
-///
-/// # Safety
-///
-/// Only the `init` module is allowed to use this trait.
-pub unsafe trait InitData: Copy {
-    type Datee: ?Sized + HasInitData;
-
-    /// Type inference helper function.
-    #[inline(always)]
-    fn make_closure<F, E>(self, f: F) -> F
-    where
-        F: FnOnce(*mut Self::Datee) -> Result<InitOk, E>,
-    {
-        f
-    }
-}
-
 pub struct AllData<T: ?Sized>(PhantomInvariant<T>);
 
 impl<T: ?Sized> Clone for AllData<T> {
@@ -178,9 +142,15 @@ impl<T: ?Sized> Clone for AllData<T> {
 
 impl<T: ?Sized> Copy for AllData<T> {}
 
-// SAFETY: TODO.
-unsafe impl<T: ?Sized> InitData for AllData<T> {
-    type Datee = T;
+impl<T: ?Sized> AllData<T> {
+    /// Type inference helper function.
+    #[inline(always)]
+    pub fn __make_closure<F, E>(self, f: F) -> F
+    where
+        F: FnOnce(*mut T) -> Result<InitOk, E>,
+    {
+        f
+    }
 }
 
 // SAFETY: TODO.