No sizing

rand-core/src/lib.rs

@@ -43,8 +43,7 @@
 
 use core::default::Default;
 use core::convert::AsMut;
-
-#[cfg(all(feature="alloc", not(feature="std")))] use alloc::boxed::Box;
+use core::ops::DerefMut;
 
 pub use error::{ErrorKind, Error};
 
@@ -262,30 +261,7 @@ pub trait SeedableRng: Sized {
 }
 
 
-impl<'a, R: RngCore + ?Sized> RngCore for &'a mut R {
-    #[inline]
-    fn next_u32(&mut self) -> u32 {
-        (**self).next_u32()
-    }
-
-    #[inline]
-    fn next_u64(&mut self) -> u64 {
-        (**self).next_u64()
-    }
-
-    #[inline]
-    fn fill_bytes(&mut self, dest: &mut [u8]) {
-        (**self).fill_bytes(dest)
-    }
-
-    #[inline]
-    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
-        (**self).try_fill_bytes(dest)
-    }
-}
-
-#[cfg(any(feature="std", feature="alloc"))]
-impl<R: RngCore + ?Sized> RngCore for Box<R> {
+impl<R: RngCore + ?Sized, T: DerefMut<Target = R>> RngCore for T {
     #[inline]
     fn next_u32(&mut self) -> u32 {
         (**self).next_u32()

src/lib.rs

@@ -342,16 +342,11 @@ pub trait Rand : Sized {
 /// ```rust
 /// use rand::Rng;
 /// 
-/// fn use_rng<R: Rng>(rng: &mut R) -> f32 {
+/// fn use_rng<R: Rng + ?Sized>(rng: &mut R) -> f32 {
 ///     rng.gen()
 /// }
 /// ```
 /// 
-/// Since this trait exclusively uses generic methods, it is marked `Sized`.
-/// Should it be necessary to support trait objects, use [`RngCore`].
-/// Since `Rng` extends `RngCore` and every `RngCore` implements `Rng`, usage
-/// of the two traits is somewhat interchangeable.
-/// 
 /// Iteration over an `Rng` can be achieved using `iter::repeat` as follows:
 /// 
 /// ```rust
@@ -378,7 +373,7 @@ pub trait Rand : Sized {
 /// ```
 /// 
 /// [`RngCore`]: https://docs.rs/rand-core/0.1/rand-core/trait.RngCore.html
-pub trait Rng: RngCore + Sized {
+pub trait Rng: RngCore {
     /// Fill `dest` entirely with random bytes (uniform value distribution),
     /// where `dest` is any type supporting [`AsByteSliceMut`], namely slices
     /// and arrays over primitive integer types (`i8`, `i16`, `u32`, etc.).
@@ -402,7 +397,7 @@ pub trait Rng: RngCore + Sized {
     /// [`fill_bytes`]: https://docs.rs/rand-core/0.1/rand-core/trait.RngCore.html#method.fill_bytes
     /// [`try_fill`]: trait.Rng.html#method.try_fill
     /// [`AsByteSliceMut`]: trait.AsByteSliceMut.html
-    fn fill<T: AsByteSliceMut + ?Sized>(&mut self, dest: &mut T) where Self: Sized {
+    fn fill<T: AsByteSliceMut + ?Sized>(&mut self, dest: &mut T) {
         self.fill_bytes(dest.as_byte_slice_mut());
         dest.to_le();
     }
@@ -438,7 +433,7 @@ pub trait Rng: RngCore + Sized {
     /// [`try_fill_bytes`]: https://docs.rs/rand-core/0.1/rand-core/trait.RngCore.html#method.try_fill_bytes
     /// [`fill`]: trait.Rng.html#method.fill
     /// [`AsByteSliceMut`]: trait.AsByteSliceMut.html
-    fn try_fill<T: AsByteSliceMut + ?Sized>(&mut self, dest: &mut T) -> Result<(), Error> where Self: Sized {
+    fn try_fill<T: AsByteSliceMut + ?Sized>(&mut self, dest: &mut T) -> Result<(), Error> {
         self.try_fill_bytes(dest.as_byte_slice_mut())?;
         dest.to_le();
         Ok(())
@@ -455,7 +450,7 @@ pub trait Rng: RngCore + Sized {
     /// let mut rng = thread_rng();
     /// let x: i32 = rng.sample(Range::new(10, 15));
     /// ```
-    fn sample<T, D: Distribution<T>>(&mut self, distr: D) -> T where Self: Sized {
+    fn sample<T, D: Distribution<T>>(&mut self, distr: D) -> T {
         distr.sample(self)
     }