Fix #1082 (seed_from_u64 with non multiple of 4)

Author: dhardy

rand_core/CHANGELOG.md

@@ -4,7 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [0.6.1] - 2020-12-31
+## [0.6.1] - 2021-01-03
+### Fixed
+- Avoid panic when using `RngCore::seed_from_u64` with a seed which is not a
+  multiple of four (#1082)
 ### Other
 - Enable all stable features in the playground (#1081)
 

rand_core/src/lib.rs

@@ -313,7 +313,7 @@ pub trait SeedableRng: Sized {
             let xorshifted = (((state >> 18) ^ state) >> 27) as u32;
             let rot = (state >> 59) as u32;
             let x = xorshifted.rotate_right(rot);
-            chunk.copy_from_slice(&x.to_le_bytes());
+            chunk.copy_from_slice(&x.to_le_bytes()[..chunk.len()]);
         }
 
         Self::from_seed(seed)