Merge pull request #2893 from g-k/2888-rand-0.8

update rand crate to 0.8

.vscode/cspell.dictionaries/acronyms+names.wordlist.txt

@@ -35,6 +35,7 @@ WASM
 XFS
 aarch
 flac
+impls
 lzma
 
 # * names

.vscode/cspell.dictionaries/jargon.wordlist.txt

@@ -28,6 +28,7 @@ devs
 discoverability
 duplicative
 dsync
+endianness
 enqueue
 errored
 executable

Cargo.lock

@@ -267,15 +267,6 @@ dependencies = [
  "clap 3.0.10",
 ]
 
-[[package]]
-name = "cloudabi"
-version = "0.0.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
-dependencies = [
- "bitflags",
-]
-
 [[package]]
 name = "compare"
 version = "0.1.0"
@@ -312,7 +303,7 @@ dependencies = [
  "libc",
  "nix 0.23.1",
  "pretty_assertions",
- "rand 0.7.3",
+ "rand",
  "regex",
  "rlimit",
  "selinux",
@@ -672,7 +663,7 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "68df3f2b690c1b86e65ef7830956aededf3cb0a16f898f79b9a6f421a7b6211b"
 dependencies = [
- "rand 0.8.4",
+ "rand",
 ]
 
 [[package]]
@@ -701,9 +692,9 @@ checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
 
 [[package]]
 name = "env_logger"
-version = "0.7.1"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
+checksum = "a19187fea3ac7e84da7dacf48de0c45d63c6a76f9490dae389aead16c243fce3"
 dependencies = [
  "log",
  "regex",
@@ -792,12 +783,6 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "fuchsia-cprng"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
-
 [[package]]
 name = "gcd"
 version = "2.1.0"
@@ -826,17 +811,6 @@ dependencies = [
  "unicode-width",
 ]
 
-[[package]]
-name = "getrandom"
-version = "0.1.16"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8fc3cb4d91f53b50155bdcfd23f6a4c39ae1969c2ae85982b135750cccaf5fce"
-dependencies = [
- "cfg-if 1.0.0",
- "libc",
- "wasi 0.9.0+wasi-snapshot-preview1",
-]
-
 [[package]]
 name = "getrandom"
 version = "0.2.4"
@@ -845,7 +819,7 @@ checksum = "418d37c8b1d42553c93648be529cb70f920d3baf8ef469b74b9638df426e0b4c"
 dependencies = [
  "cfg-if 1.0.0",
  "libc",
- "wasi 0.10.2+wasi-snapshot-preview1",
+ "wasi",
 ]
 
 [[package]]
@@ -1470,14 +1444,13 @@ checksum = "a993555f31e5a609f617c12db6250dedcac1b0a85076912c436e6fc9b2c8e6a3"
 
 [[package]]
 name = "quickcheck"
-version = "0.9.2"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a44883e74aa97ad63db83c4bf8ca490f02b2fc02f92575e720c8551e843c945f"
+checksum = "588f6378e4dd99458b60ec275b4477add41ce4fa9f64dcba6f15adccb19b50d6"
 dependencies = [
- "env_logger 0.7.1",
+ "env_logger 0.8.4",
  "log",
- "rand 0.7.3",
+ "rand",
- "rand_core 0.5.1",
 ]
 
 [[package]]
@@ -1495,33 +1468,6 @@ dependencies = [
  "proc-macro2",
 ]
 
-[[package]]
-name = "rand"
-version = "0.5.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c618c47cd3ebd209790115ab837de41425723956ad3ce2e6a7f09890947cacb9"
-dependencies = [
- "cloudabi",
- "fuchsia-cprng",
- "libc",
- "rand_core 0.3.1",
- "winapi 0.3.9",
-]
-
-[[package]]
-name = "rand"
-version = "0.7.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a6b1679d49b24bbfe0c803429aa1874472f50d9b363131f0e89fc356b544d03"
-dependencies = [
- "getrandom 0.1.16",
- "libc",
- "rand_chacha 0.2.2",
- "rand_core 0.5.1",
- "rand_hc 0.2.0",
- "rand_pcg",
-]
-
 [[package]]
 name = "rand"
 version = "0.8.4"
@@ -1529,19 +1475,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2e7573632e6454cf6b99d7aac4ccca54be06da05aca2ef7423d22d27d4d4bcd8"
 dependencies = [
  "libc",
- "rand_chacha 0.3.1",
+ "rand_chacha",
- "rand_core 0.6.3",
+ "rand_core",
- "rand_hc 0.3.1",
+ "rand_hc",
-]
-
-[[package]]
-name = "rand_chacha"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f4c8ed856279c9737206bf725bf36935d8666ead7aa69b52be55af369d193402"
-dependencies = [
- "ppv-lite86",
- "rand_core 0.5.1",
 ]
 
 [[package]]
@@ -1551,31 +1487,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
 dependencies = [
  "ppv-lite86",
- "rand_core 0.6.3",
+ "rand_core",
-]
-
-[[package]]
-name = "rand_core"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
-dependencies = [
- "rand_core 0.4.2",
-]
-
-[[package]]
-name = "rand_core"
-version = "0.4.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9c33a3c44ca05fa6f1807d8e6743f3824e8509beca625669633be0acbdf509dc"
-
-[[package]]
-name = "rand_core"
-version = "0.5.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
-dependencies = [
- "getrandom 0.1.16",
 ]
 
 [[package]]
@@ -1584,16 +1496,7 @@ version = "0.6.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
 dependencies = [
- "getrandom 0.2.4",
+ "getrandom",
-]
-
-[[package]]
-name = "rand_hc"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ca3129af7b92a17112d59ad498c6f81eaf463253766b90396d39ea7a39d6613c"
-dependencies = [
- "rand_core 0.5.1",
 ]
 
 [[package]]
@@ -1602,16 +1505,7 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d51e9f596de227fda2ea6c84607f5558e196eeaf43c986b724ba4fb8fdf497e7"
 dependencies = [
- "rand_core 0.6.3",
+ "rand_core",
-]
-
-[[package]]
-name = "rand_pcg"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "16abd0c1b639e9eb4d7c50c0b8100b0d0f849be2349829c740fe8e6eb4816429"
-dependencies = [
- "rand_core 0.5.1",
 ]
 
 [[package]]
@@ -2429,7 +2323,7 @@ dependencies = [
  "num-traits",
  "paste 0.1.18",
  "quickcheck",
- "rand 0.7.3",
+ "rand",
  "smallvec",
  "uucore",
  "uucore_procs",
@@ -2652,7 +2546,7 @@ name = "uu_mktemp"
 version = "0.0.12"
 dependencies = [
  "clap 3.0.10",
- "rand 0.5.6",
+ "rand",
  "tempfile",
  "uucore",
  "uucore_procs",
@@ -2917,7 +2811,7 @@ version = "0.0.12"
 dependencies = [
  "clap 3.0.10",
  "libc",
- "rand 0.7.3",
+ "rand",
  "uucore",
  "uucore_procs",
 ]
@@ -2927,7 +2821,8 @@ name = "uu_shuf"
 version = "0.0.12"
 dependencies = [
  "clap 3.0.10",
- "rand 0.5.6",
+ "rand",
+ "rand_core",
  "uucore",
  "uucore_procs",
 ]
@@ -2953,7 +2848,7 @@ dependencies = [
  "itertools 0.10.3",
  "memchr 2.4.1",
  "ouroboros",
- "rand 0.7.3",
+ "rand",
  "rayon",
  "tempfile",
  "unicode-width",
@@ -3304,12 +3199,6 @@ dependencies = [
  "winapi-util",
 ]
 
-[[package]]
-name = "wasi"
-version = "0.9.0+wasi-snapshot-preview1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
-
 [[package]]
 name = "wasi"
 version = "0.10.2+wasi-snapshot-preview1"

Cargo.toml

@@ -369,7 +369,7 @@ filetime = "0.2"
 glob = "0.3.0"
 libc = "0.2"
 pretty_assertions = "1"
-rand = "0.7"
+rand = "0.8"
 regex = "1.0"
 sha1 = { version="0.6", features=["std"] }
 tempfile = "3.2.0"

src/uu/factor/Cargo.toml

@@ -18,14 +18,14 @@ num-traits = "0.2.13" # used in src/numerics.rs, which is included by build.rs
 clap = { version = "3.0", features = ["wrap_help", "cargo"] }
 coz = { version = "0.1.3", optional = true }
 num-traits = "0.2.13" # Needs at least version 0.2.13 for "OverflowingAdd"
-rand = { version = "0.7", features = ["small_rng"] }
+rand = { version = "0.8", features = ["small_rng"] }
 smallvec = "1.7"  # TODO(nicoo): Use `union` feature, requires Rust 1.49 or later.
 uucore = { version = ">=0.0.8", package = "uucore", path = "../../uucore" }
 uucore_procs = { version=">=0.0.8", package = "uucore_procs", path = "../../uucore_procs" }
 
 [dev-dependencies]
 paste = "0.1.18"
-quickcheck = "0.9.2"
+quickcheck = "1.0.3"
 
 
 [[bin]]

src/uu/factor/src/factor.rs

@@ -258,7 +258,7 @@ impl Distribution<Factors> for Standard {
         // See Generating Random Factored Numbers, Easily, J. Cryptology (2003)
         'attempt: loop {
             while n > 1 {
-                n = rng.gen_range(1, n);
+                n = rng.gen_range(1..n);
                 if miller_rabin::is_prime(n) {
                     if let Some(h) = g.checked_mul(n) {
                         f.push(n);
@@ -277,8 +277,8 @@ impl Distribution<Factors> for Standard {
 
 #[cfg(test)]
 impl quickcheck::Arbitrary for Factors {
-    fn arbitrary<G: quickcheck::Gen>(g: &mut G) -> Self {
+    fn arbitrary(g: &mut quickcheck::Gen) -> Self {
-        g.gen()
+        factor(u64::arbitrary(g))
     }
 }
 

src/uu/factor/src/miller_rabin.rs

@@ -200,7 +200,11 @@ mod tests {
 
     quickcheck! {
         fn composites(i: u64, j: u64) -> bool {
-            i < 2 || j < 2 || !is_prime(i*j)
+            // TODO: #1559 factor n > 2^64 - 1
+            match i.checked_mul(j) {
+                Some(n) => i < 2 || j < 2 || !is_prime(n),
+                _ => true,
+            }
         }
     }
 }

src/uu/factor/src/numeric/gcd.rs

@@ -6,6 +6,8 @@
 // * For the full copyright and license information, please view the LICENSE file
 // * that was distributed with this source code.
 
+// spell-checker:ignore (vars) kgcdab gcdac gcdbc
+
 use std::cmp::min;
 use std::mem::swap;
 
@@ -93,16 +95,35 @@ mod tests {
         }
 
         fn scalar_multiplication(a: u64, b: u64, k: u64) -> bool {
-            gcd(k * a, k * b) == k * gcd(a, b)
+            // TODO: #1559 factor n > 2^64 - 1
+            match (k.checked_mul(a), k.checked_mul(b), k.checked_mul(gcd(a, b))) {
+                (Some(ka), Some(kb), Some(kgcdab)) => gcd(ka, kb) == kgcdab,
+                _ => true
+            }
         }
 
         fn multiplicative(a: u64, b: u64, c: u64) -> bool {
-            // gcd(ab, c) = gcd(a, c) gcd(b, c) when a and b coprime
+            // TODO: #1559 factor n > 2^64 - 1
-            gcd(a, b) != 1 || gcd(a * b, c) == gcd(a, c) * gcd(b, c)
+            match (a.checked_mul(b), gcd(a, c).checked_mul(gcd(b, c))) {
+                (Some(ab), Some(gcdac_gcdbc)) => {
+                    // gcd(ab, c) = gcd(a, c) gcd(b, c) when a and b coprime
+                    gcd(a, b) != 1 || gcd(ab, c) == gcdac_gcdbc
+                },
+                _ => true,
+            }
         }
 
         fn linearity(a: u64, b: u64, k: u64) -> bool {
-            gcd(a + k * b, b) == gcd(a, b)
+            // TODO: #1559 factor n > 2^64 - 1
+            match k.checked_mul(b) {
+                Some(kb) => {
+                    match a.checked_add(kb) {
+                        Some(a_plus_kb) => gcd(a_plus_kb, b) == gcd(a, b),
+                        _ => true,
+                    }
+                }
+                _ => true,
+            }
         }
     }
 }

src/uu/factor/src/numeric/modular_inverse.rs

@@ -63,13 +63,17 @@ mod tests {
 
     quickcheck! {
         fn random_values_u32(n: u32) -> bool {
-            let n = 2 * n + 1;
+            match 2_u32.checked_mul(n) {
-            modular_inverse(n).wrapping_mul(n) == 1
+                Some(n) => modular_inverse(n + 1).wrapping_mul(n + 1) == 1,
+                _ => true,
+            }
         }
 
         fn random_values_u64(n: u64) -> bool {
-            let n = 2 * n + 1;
+            match 2_u64.checked_mul(n) {
-            modular_inverse(n).wrapping_mul(n) == 1
+                Some(n) => modular_inverse(n + 1).wrapping_mul(n + 1) == 1,
+                _ => true,
+            }
         }
     }
 }

src/uu/mktemp/Cargo.toml

@@ -16,7 +16,7 @@ path = "src/mktemp.rs"
 
 [dependencies]
 clap = { version = "3.0", features = ["wrap_help", "cargo"] }
-rand = "0.5"
+rand = "0.8"
 tempfile = "3.1"
 uucore = { version=">=0.0.11", package="uucore", path="../../uucore" }
 uucore_procs = { version=">=0.0.8", package="uucore_procs", path="../../uucore_procs" }

src/uu/shred/Cargo.toml

@@ -17,7 +17,7 @@ path = "src/shred.rs"
 [dependencies]
 clap = { version = "3.0", features = ["wrap_help", "cargo"] }
 libc = "0.2.42"
-rand = "0.7"
+rand = "0.8"
 uucore = { version=">=0.0.11", package="uucore", path="../../uucore" }
 uucore_procs = { version=">=0.0.8", package="uucore_procs", path="../../uucore_procs" }
 

src/uu/shuf/Cargo.toml

@@ -16,7 +16,8 @@ path = "src/shuf.rs"
 
 [dependencies]
 clap = { version = "3.0", features = ["wrap_help", "cargo"] }
-rand = "0.5"
+rand = "0.8"
+rand_core = "0.6"
 uucore = { version=">=0.0.11", package="uucore", path="../../uucore" }
 uucore_procs = { version=">=0.0.8", package="uucore_procs", path="../../uucore_procs" }
 

src/uu/shuf/src/rand_read_adapter.rs

@@ -0,0 +1,144 @@
+// Copyright 2018 Developers of the Rand project.
+// Copyright 2013 The Rust Project Developers.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! A wrapper around any Read to treat it as an RNG.
+
+use std::fmt;
+use std::io::Read;
+
+use rand_core::{impls, Error, RngCore};
+
+/// An RNG that reads random bytes straight from any type supporting
+/// [`std::io::Read`], for example files.
+///
+/// This will work best with an infinite reader, but that is not required.
+///
+/// This can be used with `/dev/urandom` on Unix but it is recommended to use
+/// [`OsRng`] instead.
+///
+/// # Panics
+///
+/// `ReadRng` uses [`std::io::Read::read_exact`], which retries on interrupts.
+/// All other errors from the underlying reader, including when it does not
+/// have enough data, will only be reported through [`try_fill_bytes`].
+/// The other [`RngCore`] methods will panic in case of an error.
+///
+/// [`OsRng`]: crate::rngs::OsRng
+/// [`try_fill_bytes`]: RngCore::try_fill_bytes
+#[derive(Debug)]
+pub struct ReadRng<R> {
+    reader: R,
+}
+
+impl<R: Read> ReadRng<R> {
+    /// Create a new `ReadRng` from a `Read`.
+    pub fn new(r: R) -> ReadRng<R> {
+        ReadRng { reader: r }
+    }
+}
+
+impl<R: Read> RngCore for ReadRng<R> {
+    fn next_u32(&mut self) -> u32 {
+        impls::next_u32_via_fill(self)
+    }
+
+    fn next_u64(&mut self) -> u64 {
+        impls::next_u64_via_fill(self)
+    }
+
+    fn fill_bytes(&mut self, dest: &mut [u8]) {
+        self.try_fill_bytes(dest).unwrap_or_else(|err| {
+            panic!(
+                "reading random bytes from Read implementation failed; error: {}",
+                err
+            )
+        });
+    }
+
+    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
+        if dest.is_empty() {
+            return Ok(());
+        }
+        // Use `std::io::read_exact`, which retries on `ErrorKind::Interrupted`.
+        self.reader
+            .read_exact(dest)
+            .map_err(|e| Error::new(ReadError(e)))
+    }
+}
+
+/// `ReadRng` error type
+#[derive(Debug)]
+pub struct ReadError(std::io::Error);
+
+impl fmt::Display for ReadError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "ReadError: {}", self.0)
+    }
+}
+
+impl std::error::Error for ReadError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        Some(&self.0)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use std::println;
+
+    use super::ReadRng;
+    use rand::RngCore;
+
+    #[test]
+    fn test_reader_rng_u64() {
+        // transmute from the target to avoid endianness concerns.
+        #[rustfmt::skip]
+        let v = [0u8, 0, 0, 0, 0, 0, 0, 1,
+                 0,   4, 0, 0, 3, 0, 0, 2,
+                 5,   0, 0, 0, 0, 0, 0, 0];
+        let mut rng = ReadRng::new(&v[..]);
+
+        assert_eq!(rng.next_u64(), 1 << 56);
+        assert_eq!(rng.next_u64(), (2 << 56) + (3 << 32) + (4 << 8));
+        assert_eq!(rng.next_u64(), 5);
+    }
+
+    #[test]
+    fn test_reader_rng_u32() {
+        let v = [0u8, 0, 0, 1, 0, 0, 2, 0, 3, 0, 0, 0];
+        let mut rng = ReadRng::new(&v[..]);
+
+        assert_eq!(rng.next_u32(), 1 << 24);
+        assert_eq!(rng.next_u32(), 2 << 16);
+        assert_eq!(rng.next_u32(), 3);
+    }
+
+    #[test]
+    fn test_reader_rng_fill_bytes() {
+        let v = [1u8, 2, 3, 4, 5, 6, 7, 8];
+        let mut w = [0u8; 8];
+
+        let mut rng = ReadRng::new(&v[..]);
+        rng.fill_bytes(&mut w);
+
+        assert!(v == w);
+    }
+
+    #[test]
+    fn test_reader_rng_insufficient_bytes() {
+        let v = [1u8, 2, 3, 4, 5, 6, 7, 8];
+        let mut w = [0u8; 9];
+
+        let mut rng = ReadRng::new(&v[..]);
+
+        let result = rng.try_fill_bytes(&mut w);
+        assert!(result.is_err());
+        println!("Error: {}", result.unwrap_err());
+    }
+}

src/uu/shuf/src/shuf.rs

@@ -15,6 +15,8 @@ use uucore::display::Quotable;
 use uucore::error::{FromIo, UResult, USimpleError};
 use uucore::InvalidEncodingHandling;
 
+mod rand_read_adapter;
+
 enum Mode {
     Default(String),
     Echo(Vec<String>),
@@ -244,7 +246,7 @@ fn shuf_bytes(input: &mut Vec<&[u8]>, opts: Options) -> UResult<()> {
         Some(r) => {
             let file = File::open(&r[..])
                 .map_err_context(|| format!("failed to open random source {}", r.quote()))?;
-            WrappedRng::RngFile(rand::rngs::adapter::ReadRng::new(file))
+            WrappedRng::RngFile(rand_read_adapter::ReadRng::new(file))
         }
         None => WrappedRng::RngDefault(rand::thread_rng()),
     };
@@ -302,7 +304,7 @@ fn parse_range(input_range: &str) -> Result<(usize, usize), String> {
 }
 
 enum WrappedRng {
-    RngFile(rand::rngs::adapter::ReadRng<File>),
+    RngFile(rand_read_adapter::ReadRng<File>),
     RngDefault(rand::rngs::ThreadRng),
 }
 

src/uu/sort/Cargo.toml

@@ -23,7 +23,7 @@ fnv = "1.0.7"
 itertools = "0.10.0"
 memchr = "2.4.0"
 ouroboros = "0.10.1"
-rand = "0.7"
+rand = "0.8"
 rayon = "1.5"
 tempfile = "3"
 unicode-width = "0.1.8"

tests/benches/factor/Cargo.toml

@@ -13,7 +13,7 @@ uu_factor = { path = "../../../src/uu/factor" }
 [dev-dependencies]
 array-init = "2.0.0"
 criterion = "0.3"
-rand = "0.7"
+rand = "0.8"
 rand_chacha = "0.2.2"
 
 

tests/by-util/test_factor.rs

@@ -115,7 +115,7 @@ fn test_random() {
             // log distribution---higher probability for lower numbers
             let factor;
             loop {
-                let next = rng.gen_range(0_f64, log_num_primes).exp2().floor() as usize;
+                let next = rng.gen_range(0_f64..log_num_primes).exp2().floor() as usize;
                 if next < NUM_PRIMES {
                     factor = primes[next];
                     break;

tests/by-util/test_split.rs

@@ -22,6 +22,7 @@ use std::{
 fn random_chars(n: usize) -> String {
     thread_rng()
         .sample_iter(&rand::distributions::Alphanumeric)
+        .map(char::from)
         .take(n)
         .collect::<String>()
 }