Bump MSRV to 1.56 (Edition 2021)

.github/workflows/test.yml

@@ -43,7 +43,7 @@ jobs:
             # Test both windows-gnu and windows-msvc; use beta rust on one
           - os: ubuntu-latest
             target: x86_64-unknown-linux-gnu
-            toolchain: 1.51.0 # MSRV
+            toolchain: 1.56.0 # MSRV
           - os: ubuntu-latest
             deps: sudo apt-get update ; sudo apt install gcc-multilib
             target: i686-unknown-linux-gnu

Cargo.toml

@@ -13,7 +13,8 @@ Random number generators and other randomness functionality.
 keywords = ["random", "rng"]
 categories = ["algorithms", "no-std"]
 autobenches = true
-edition = "2018"
+edition = "2021"
+rust-version = "1.56"
 include = ["src/", "LICENSE-*", "README.md", "CHANGELOG.md", "COPYRIGHT"]
 
 [package.metadata.docs.rs]

README.md

@@ -5,7 +5,7 @@
 [![Book](https://img.shields.io/badge/book-master-yellow.svg)](https://rust-random.github.io/book/)
 [![API](https://img.shields.io/badge/api-master-yellow.svg)](https://rust-random.github.io/rand/rand)
 [![API](https://docs.rs/rand/badge.svg)](https://docs.rs/rand)
-[![Minimum rustc version](https://img.shields.io/badge/rustc-1.51+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
+[![Minimum rustc version](https://img.shields.io/badge/rustc-1.56+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
 
 A Rust library for random number generation, featuring:
 
@@ -95,9 +95,10 @@ Some versions of Rand crates have been yanked ("unreleased"). Where this occurs,
 the crate's CHANGELOG *should* be updated with a rationale, and a search on the
 issue tracker with the keyword `yank` *should* uncover the motivation.
 
-### Rust version requirements (MSRV)
+### Rust version requirements
 
-This version of Rand requires Rustc >= 1.51.0.
+The Minimum Supported Rust Version (MSRV) is `rustc >= 1.56.0`.
+Older releases may work (depending on feature configuration) but are untested.
 
 ## Crate Features
 

rand_chacha/Cargo.toml

@@ -12,7 +12,8 @@ ChaCha random number generator
 """
 keywords = ["random", "rng", "chacha"]
 categories = ["algorithms", "no-std"]
-edition = "2018"
+edition = "2021"
+rust-version = "1.56"
 
 [dependencies]
 rand_core = { path = "../rand_core", version = "0.6.0" }

rand_chacha/README.md

@@ -5,7 +5,7 @@
 [![Book](https://img.shields.io/badge/book-master-yellow.svg)](https://rust-random.github.io/book/)
 [![API](https://img.shields.io/badge/api-master-yellow.svg)](https://rust-random.github.io/rand/rand_chacha)
 [![API](https://docs.rs/rand_chacha/badge.svg)](https://docs.rs/rand_chacha)
-[![Minimum rustc version](https://img.shields.io/badge/rustc-1.51+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
+[![Minimum rustc version](https://img.shields.io/badge/rustc-1.56+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
 
 A cryptographically secure random number generator that uses the ChaCha
 algorithm.

rand_core/Cargo.toml

@@ -12,7 +12,8 @@ Core random number generator traits and tools for implementation.
 """
 keywords = ["random", "rng"]
 categories = ["algorithms", "no-std"]
-edition = "2018"
+edition = "2021"
+rust-version = "1.56"
 
 [package.metadata.docs.rs]
 # To build locally:

rand_core/README.md

@@ -5,7 +5,7 @@
 [![Book](https://img.shields.io/badge/book-master-yellow.svg)](https://rust-random.github.io/book/)
 [![API](https://img.shields.io/badge/api-master-yellow.svg)](https://rust-random.github.io/rand/rand_core)
 [![API](https://docs.rs/rand_core/badge.svg)](https://docs.rs/rand_core)
-[![Minimum rustc version](https://img.shields.io/badge/rustc-1.51+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
+[![Minimum rustc version](https://img.shields.io/badge/rustc-1.56+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
 
 Core traits and error types of the [rand] library, plus tools for implementing
 RNGs.

rand_core/src/block.rs

@@ -381,13 +381,13 @@ impl<R: BlockRngCore<Item = u64>> RngCore for BlockRng64<R> {
         let mut read_len = 0;
         self.half_used = false;
         while read_len < dest.len() {
-            if self.index as usize >= self.results.as_ref().len() {
+            if self.index >= self.results.as_ref().len() {
                 self.core.generate(&mut self.results);
                 self.index = 0;
             }
 
             let (consumed_u64, filled_u8) = fill_via_u64_chunks(
-                &self.results.as_ref()[self.index as usize..],
+                &self.results.as_ref()[self.index..],
                 &mut dest[read_len..],
             );
 

rand_distr/Cargo.toml

@@ -12,7 +12,8 @@ Sampling from random number distributions
 """
 keywords = ["random", "rng", "distribution", "probability"]
 categories = ["algorithms", "no-std"]
-edition = "2018"
+edition = "2021"
+rust-version = "1.56"
 include = ["src/", "LICENSE-*", "README.md", "CHANGELOG.md", "COPYRIGHT"]
 
 [features]

rand_distr/README.md

@@ -5,7 +5,7 @@
 [![Book](https://img.shields.io/badge/book-master-yellow.svg)](https://rust-random.github.io/book/)
 [![API](https://img.shields.io/badge/api-master-yellow.svg)](https://rust-random.github.io/rand/rand_distr)
 [![API](https://docs.rs/rand_distr/badge.svg)](https://docs.rs/rand_distr)
-[![Minimum rustc version](https://img.shields.io/badge/rustc-1.51+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
+[![Minimum rustc version](https://img.shields.io/badge/rustc-1.56+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
 
 Implements a full suite of random number distribution sampling routines.
 

rand_distr/benches/Cargo.toml

@@ -4,7 +4,8 @@ version = "0.0.0"
 authors = ["The Rand Project Developers"]
 license = "MIT OR Apache-2.0"
 description = "Criterion benchmarks of the rand_distr crate"
-edition = "2018"
+edition = "2021"
+rust-version = "1.56"
 publish = false
 
 [workspace]
@@ -19,4 +20,4 @@ rand_pcg = { path = "../../rand_pcg/" }
 [[bench]]
 name = "distributions"
 path = "src/distributions.rs"
-harness = false
+harness = false

rand_pcg/Cargo.toml

@@ -12,7 +12,8 @@ Selected PCG random number generators
 """
 keywords = ["random", "rng", "pcg"]
 categories = ["algorithms", "no-std"]
-edition = "2018"
+edition = "2021"
+rust-version = "1.56"
 
 [features]
 serde1 = ["serde"]

rand_pcg/README.md

@@ -5,7 +5,7 @@
 [![Book](https://img.shields.io/badge/book-master-yellow.svg)](https://rust-random.github.io/book/)
 [![API](https://img.shields.io/badge/api-master-yellow.svg)](https://rust-random.github.io/rand/rand_pcg)
 [![API](https://docs.rs/rand_pcg/badge.svg)](https://docs.rs/rand_pcg)
-[![Minimum rustc version](https://img.shields.io/badge/rustc-1.51+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
+[![Minimum rustc version](https://img.shields.io/badge/rustc-1.56+-lightgray.svg)](https://github.com/rust-random/rand#rust-version-requirements)
 
 Implements a selection of PCG random number generators.
 

rustfmt.toml

@@ -19,7 +19,7 @@ where_single_line = true
 # struct_field_align_threshold = 20
 
 # Compatibility:
-edition = "2018"        # we require compatibility back to 1.32.0
+edition = "2021"
 
 # Misc:
 inline_attribute_width = 80

src/distributions/uniform.rs

@@ -340,7 +340,7 @@ where Borrowed: SampleUniform
 {
     #[inline(always)]
     fn borrow(&self) -> &Borrowed {
-        *self
+        self
     }
 }
 

src/rngs/adapter/reseeding.rs

@@ -208,8 +208,8 @@ where
         ReseedingCore {
             inner: rng,
             reseeder,
-            threshold: threshold as i64,
-            bytes_until_reseed: threshold as i64,
+            threshold,
+            bytes_until_reseed: threshold,
             fork_counter: 0,
         }
     }

src/seq/index.rs

@@ -238,7 +238,7 @@ where R: Rng + ?Sized {
 
     if amount < 163 {
         const C: [[f32; 2]; 2] = [[1.6, 8.0 / 45.0], [10.0, 70.0 / 9.0]];
-        let j = if length < 500_000 { 0 } else { 1 };
+        let j = usize::from(length >= 500_000);
         let amount_fp = amount as f32;
         let m4 = C[0][j] * amount_fp;
         // Short-cut: when amount < 12, floyd's is always faster
@@ -249,7 +249,7 @@ where R: Rng + ?Sized {
         }
     } else {
         const C: [f32; 2] = [270.0, 330.0 / 9.0];
-        let j = if length < 500_000 { 0 } else { 1 };
+        let j = usize::from(length >= 500_000);
         if (length as f32) < C[j] * (amount as f32) {
             sample_inplace(rng, length, amount)
         } else {

src/seq/mod.rs

@@ -641,7 +641,7 @@ impl<'a, S: Index<usize, Output = T> + ?Sized + 'a, T: 'a> Iterator for SliceCho
 
     fn next(&mut self) -> Option<Self::Item> {
         // TODO: investigate using SliceIndex::get_unchecked when stable
-        self.indices.next().map(|i| &self.slice[i as usize])
+        self.indices.next().map(|i| &self.slice[i])
     }
 
     fn size_hint(&self) -> (usize, Option<usize>) {