From 685d4ebe45627caf1b9072f93ab894500a72a224 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?=
 <martin.kroening@eonerc.rwth-aachen.de>
Date: Thu, 25 Apr 2024 16:53:57 +0200
Subject: [PATCH] fix(access): properly seal access traits
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Signed-off-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>
---
 src/access.rs | 42 +++++++++++++-----------------------------
 1 file changed, 13 insertions(+), 29 deletions(-)

diff --git a/src/access.rs b/src/access.rs
index 42d4ec6..6d529bd 100644
--- a/src/access.rs
+++ b/src/access.rs
@@ -1,43 +1,22 @@
 //! Marker types for limiting access.
 
-/// Private trait that is implemented for the types in this module.
-pub trait Access: Copy + Default {
-    /// Ensures that this trait cannot be implemented outside of this crate.
-    #[doc(hidden)]
-    fn _private() -> _Private {
-        _Private
-    }
-
+/// Sealed trait that is implemented for the types in this module.
+pub trait Access: Copy + Default + private::Sealed {
     /// Reduced access level to safely share the corresponding value.
     type RestrictShared: Access;
 }
 
 /// Helper trait that is implemented by [`ReadWrite`] and [`ReadOnly`].
-pub trait Readable: Copy + Default {
+pub trait Readable: Copy + Default + private::Sealed {
     /// Reduced access level to safely share the corresponding value.
     type RestrictShared: Readable + Access;
-
-    /// Ensures that this trait cannot be implemented outside of this crate.
-    fn _private() -> _Private {
-        _Private
-    }
 }
 
 /// Helper trait that is implemented by [`ReadWrite`] and [`WriteOnly`].
-pub trait Writable: Access {
-    /// Ensures that this trait cannot be implemented outside of this crate.
-    fn _private() -> _Private {
-        _Private
-    }
-}
+pub trait Writable: Access + private::Sealed {}
 
 /// Implemented for access types that permit copying of `VolatileRef`.
-pub trait Copyable {
-    /// Ensures that this trait cannot be implemented outside of this crate.
-    fn _private() -> _Private {
-        _Private
-    }
-}
+pub trait Copyable: private::Sealed {}
 
 impl<T> Access for T
 where
@@ -78,6 +57,11 @@ impl Access for NoAccess {
 }
 impl Copyable for NoAccess {}
 
-#[non_exhaustive]
-#[doc(hidden)]
-pub struct _Private;
+mod private {
+    pub trait Sealed {}
+
+    impl Sealed for super::ReadWrite {}
+    impl Sealed for super::ReadOnly {}
+    impl Sealed for super::WriteOnly {}
+    impl Sealed for super::NoAccess {}
+}