Remove unsafe from from_seed

src/lib.rs

@@ -250,7 +250,7 @@
 #[cfg(feature="std")] extern crate std as core;
 #[cfg(all(feature = "alloc", not(feature="std")))] extern crate alloc;
 
-use core::{marker, mem, slice};
+use core::{marker, mem};
 #[cfg(feature="std")] use std::cell::RefCell;
 #[cfg(feature="std")] use std::rc::Rc;
 #[cfg(all(feature="alloc", not(feature="std")))] use alloc::boxed::Box;
@@ -762,7 +762,7 @@ pub trait SeedableRng: Sized {
     /// RNG's with partially overlapping periods.
     ///
     /// For cryptographic RNG's a seed of 256 bits is recommended, `[u8; 32]`.
-    type Seed: SeedRestriction;
+    type Seed: Sized + Default + AsMut<[u8]>;
 
     /// Create a new PRNG using the given seed.
     ///
@@ -806,12 +806,7 @@ pub trait SeedableRng: Sized {
     /// There are no reproducibility requirements like endianness conversion.
     fn from_rng<R: Rng>(mut rng: R) -> Result<Self, Error> {
         let mut seed = Self::Seed::default();
-        let size = mem::size_of::<Self::Seed>() as usize;
-        unsafe {
-            let ptr = seed.as_mut().as_mut_ptr() as *mut u8;
-            let slice = slice::from_raw_parts_mut(ptr, size);
-            rng.try_fill_bytes(slice)?;
-        }
+        rng.try_fill_bytes(seed.as_mut())?;
         Ok(Self::from_seed(seed))
     }
 }