Seal all marker traits and bump version

CHANGELOG.md

@@ -7,6 +7,11 @@ against this Rust version.
 
 ### Unreleased
 
+### 1.14.0 (2021-09-01)
+- [changed] Sealed all marker traits. Documentation already stated that these
+  should not be implemented outside the crate, so this is not considered a
+  breaking change.
+
 ### 1.13.0 (2021-03-12)
 - [changed] MSRV from 1.22.0 to 1.37.0.
 - [fixed] `op` macro with 2018 edition import.

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
   name = "typenum"
   build = "build/main.rs"
-  version = "1.13.0" # remember to update html_root_url
+  version = "1.14.0" # remember to update html_root_url
   authors = [
     "Paho Lurie-Gregg <[email protected]>",
     "Andre Bogus <[email protected]>"

src/lib.rs

@@ -59,7 +59,7 @@
     )
 )]
 #![cfg_attr(feature = "cargo-clippy", deny(clippy::missing_inline_in_public_items))]
-#![doc(html_root_url = "https://docs.rs/typenum/1.13.0")]
+#![doc(html_root_url = "https://docs.rs/typenum/1.14.0")]
 
 // For debugging macros:
 // #![feature(trace_macros)]
@@ -156,3 +156,29 @@ macro_rules! assert_type {
             core::marker::PhantomData;
     };
 }
+
+mod sealed {
+    use crate::{
+        ATerm, Bit, Equal, Greater, Less, NInt, NonZero, PInt, TArr, UInt, UTerm, Unsigned, B0, B1,
+        Z0,
+    };
+
+    pub trait Sealed {}
+
+    impl Sealed for B0 {}
+    impl Sealed for B1 {}
+
+    impl Sealed for UTerm {}
+    impl<U: Unsigned, B: Bit> Sealed for UInt<U, B> {}
+
+    impl Sealed for Z0 {}
+    impl<U: Unsigned + NonZero> Sealed for PInt<U> {}
+    impl<U: Unsigned + NonZero> Sealed for NInt<U> {}
+
+    impl Sealed for Less {}
+    impl Sealed for Equal {}
+    impl Sealed for Greater {}
+
+    impl Sealed for ATerm {}
+    impl<V, A> Sealed for TArr<V, A> {}
+}

src/marker_traits.rs

@@ -15,26 +15,24 @@
 //! assert_eq!(-42, N42::I32);
 //! ```
 
+use crate::sealed::Sealed;
+
 /// A **marker trait** to designate that a type is not zero. All number types in this
 /// crate implement `NonZero` except `B0`, `U0`, and `Z0`.
-pub trait NonZero {}
+pub trait NonZero: Sealed {}
 
 /// A **marker trait** to designate that a type is zero. Only `B0`, `U0`, and `Z0`
 /// implement this trait.
-pub trait Zero {}
+pub trait Zero: Sealed {}
 
 /// A **Marker trait** for the types `Greater`, `Equal`, and `Less`.
-///
-/// This trait should not be implemented for anything outside this crate.
-pub trait Ord {
+pub trait Ord: Sealed {
     #[allow(missing_docs)]
     fn to_ordering() -> ::core::cmp::Ordering;
 }
 
 /// The **marker trait** for compile time bits.
-///
-/// This trait should not be implemented for anything outside this crate.
-pub trait Bit: Copy + Default + 'static {
+pub trait Bit: Sealed + Copy + Default + 'static {
     #[allow(missing_docs)]
     const U8: u8;
     #[allow(missing_docs)]
@@ -51,16 +49,14 @@ pub trait Bit: Copy + Default + 'static {
 
 /// The **marker trait** for compile time unsigned integers.
 ///
-/// This trait should not be implemented for anything outside this crate.
-///
 /// # Example
 /// ```rust
 /// use typenum::{Unsigned, U3};
 ///
 /// assert_eq!(U3::to_u32(), 3);
 /// assert_eq!(U3::I32, 3);
 /// ```
-pub trait Unsigned: Copy + Default + 'static {
+pub trait Unsigned: Sealed + Copy + Default + 'static {
     #[allow(missing_docs)]
     const U8: u8;
     #[allow(missing_docs)]
@@ -120,16 +116,14 @@ pub trait Unsigned: Copy + Default + 'static {
 
 /// The **marker trait** for compile time signed integers.
 ///
-/// This trait should not be implemented for anything outside this crate.
-///
 /// # Example
 /// ```rust
 /// use typenum::{Integer, P3};
 ///
 /// assert_eq!(P3::to_i32(), 3);
 /// assert_eq!(P3::I32, 3);
 /// ```
-pub trait Integer: Copy + Default + 'static {
+pub trait Integer: Sealed + Copy + Default + 'static {
     #[allow(missing_docs)]
     const I8: i8;
     #[allow(missing_docs)]
@@ -161,17 +155,13 @@ pub trait Integer: Copy + Default + 'static {
 
 /// The **marker trait** for type-level arrays of type-level numbers.
 ///
-/// This trait should not be implemented for anything outside this crate.
-///
 /// Someday, it may contain an associated constant to produce a runtime array,
 /// like the other marker traits here. However, that is blocked by [this
 /// issue](https://github.com/rust-lang/rust/issues/44168).
-pub trait TypeArray {}
+pub trait TypeArray: Sealed {}
 
 /// The **marker trait** for type-level numbers which are a power of two.
 ///
-/// This trait should not be implemented for anything outside this crate.
-///
 /// # Examples
 ///
 /// Here's a working example:
@@ -196,5 +186,4 @@ pub trait TypeArray {}
 /// only_p2::<P511>();
 /// only_p2::<P1023>();
 /// ```
-
-pub trait PowerOfTwo {}
+pub trait PowerOfTwo: Sealed {}