Rollup merge of rust-lang#63261 - RalfJung:rand, r=nikomatsakis

bump rand in libcore/liballoc test suites

This pulls in the fix for rust-random/rand#779, which trips Miri when running these test suites.

`SmallRng` (formerly used by libcore) is no longer built by default, it needs a feature gate. I opted to switch to `StdRng` instead. Or should I enable the feature gate?

Cargo.lock

@@ -19,8 +19,8 @@ version = "0.0.0"
 dependencies = [
  "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
- "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_xorshift 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_xorshift 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -514,7 +514,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "core"
 version = "0.0.0"
 dependencies = [
- "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1050,7 +1050,7 @@ dependencies = [
 
 [[package]]
 name = "getrandom"
-version = "0.1.7"
+version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2246,7 +2246,7 @@ name = "rand"
 version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "getrandom 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "getrandom 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.60 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_chacha 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2286,7 +2286,7 @@ name = "rand_core"
 version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "getrandom 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "getrandom 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2343,6 +2343,14 @@ dependencies = [
  "rand_core 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "rand_xorshift"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rand_core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "rayon"
 version = "1.1.0"
@@ -4436,7 +4444,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum fwdansi 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "34dd4c507af68d37ffef962063dfa1944ce0dd4d5b82043dbab1dabe088610c3"
 "checksum generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ef25c5683767570c2bbd7deba372926a55eaae9982d7726ee2a1050239d45b9d"
 "checksum getopts 0.2.19 (registry+https://github.com/rust-lang/crates.io-index)" = "72327b15c228bfe31f1390f93dd5e9279587f0463836393c9df719ce62a3e450"
-"checksum getrandom 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "cd8e190892c840661957ba9f32dacfb3eb405e657f9f9f60485605f0bb37d6f8"
+"checksum getrandom 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "34f33de6f0ae7c9cb5e574502a562e2b512799e32abb801cd1e79ad952b62b49"
 "checksum git2 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)" = "8cb400360e8a4d61b10e648285bbfa919bbf9519d0d5d5720354456f44349226"
 "checksum git2-curl 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2293de73491c3dc4174c5949ef53d2cc037b27613f88d72032e3f5237247a7dd"
 "checksum glob 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
@@ -4567,6 +4575,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum rand_os 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "7b75f676a1e053fc562eafbb47838d67c84801e38fc1ba459e8f180deabd5071"
 "checksum rand_pcg 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "086bd09a33c7044e56bb44d5bdde5a60e7f119a9e95b0775f545de759a32fe05"
 "checksum rand_xorshift 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "effa3fcaa47e18db002bdde6060944b6d2f9cfd8db471c30e873448ad9187be3"
+"checksum rand_xorshift 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "77d416b86801d23dde1aa643023b775c3a462efc0ed96443add11546cdf1dca8"
 "checksum rayon 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a4b0186e22767d5b9738a05eab7c6ac90b15db17e5b5f9bd87976dd7d89a10a4"
 "checksum rayon-core 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ebbe0df8435ac0c397d467b6cad6d25543d06e8a019ef3f6af3c384597515bd2"
 "checksum rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"

src/liballoc/Cargo.toml

@@ -15,8 +15,8 @@ core = { path = "../libcore" }
 compiler_builtins = { version = "0.1.10", features = ['rustc-dep-of-std'] }
 
 [dev-dependencies]
-rand = "0.6"
-rand_xorshift = "0.1"
+rand = "0.7"
+rand_xorshift = "0.2"
 
 [[test]]
 name = "collectionstests"

src/liballoc/benches/slice.rs

@@ -186,12 +186,12 @@ const SEED: [u8; 16] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15];
 
 fn gen_random(len: usize) -> Vec<u64> {
     let mut rng = XorShiftRng::from_seed(SEED);
-    rng.sample_iter(&Standard).take(len).collect()
+    (&mut rng).sample_iter(&Standard).take(len).collect()
 }
 
 fn gen_random_bytes(len: usize) -> Vec<u8> {
     let mut rng = XorShiftRng::from_seed(SEED);
-    rng.sample_iter(&Standard).take(len).collect()
+    (&mut rng).sample_iter(&Standard).take(len).collect()
 }
 
 fn gen_mostly_ascending(len: usize) -> Vec<u64> {
@@ -221,14 +221,14 @@ fn gen_strings(len: usize) -> Vec<String> {
     let mut v = vec![];
     for _ in 0..len {
         let n = rng.gen::<usize>() % 20 + 1;
-        v.push(rng.sample_iter(&Alphanumeric).take(n).collect());
+        v.push((&mut rng).sample_iter(&Alphanumeric).take(n).collect());
     }
     v
 }
 
 fn gen_big_random(len: usize) -> Vec<[u64; 16]> {
     let mut rng = XorShiftRng::from_seed(SEED);
-    rng.sample_iter(&Standard).map(|x| [x; 16]).take(len).collect()
+    (&mut rng).sample_iter(&Standard).map(|x| [x; 16]).take(len).collect()
 }
 
 macro_rules! sort {

src/libcore/Cargo.toml

@@ -21,7 +21,7 @@ name = "corebenches"
 path = "../libcore/benches/lib.rs"
 
 [dev-dependencies]
-rand = "0.6"
+rand = "0.7"
 
 [features]
 # Make panics and failed asserts immediately abort without formatting any message

src/libcore/tests/num/flt2dec/random.rs

@@ -8,8 +8,8 @@ use core::num::flt2dec::strategy::grisu::format_exact_opt;
 use core::num::flt2dec::strategy::grisu::format_shortest_opt;
 use core::num::flt2dec::{decode, DecodableFloat, FullDecoded, Decoded};
 
-use rand::FromEntropy;
-use rand::rngs::SmallRng;
+use rand::SeedableRng;
+use rand::rngs::StdRng;
 use rand::distributions::{Distribution, Uniform};
 
 pub fn decode_finite<T: DecodableFloat>(v: T) -> Decoded {
@@ -65,7 +65,7 @@ pub fn f32_random_equivalence_test<F, G>(f: F, g: G, k: usize, n: usize)
     if cfg!(target_os = "emscripten") {
         return // using rng pulls in i128 support, which doesn't work
     }
-    let mut rng = SmallRng::from_entropy();
+    let mut rng = StdRng::from_entropy();
     let f32_range = Uniform::new(0x0000_0001u32, 0x7f80_0000);
     iterate("f32_random_equivalence_test", k, n, f, g, |_| {
         let x = f32::from_bits(f32_range.sample(&mut rng));
@@ -79,7 +79,7 @@ pub fn f64_random_equivalence_test<F, G>(f: F, g: G, k: usize, n: usize)
     if cfg!(target_os = "emscripten") {
         return // using rng pulls in i128 support, which doesn't work
     }
-    let mut rng = SmallRng::from_entropy();
+    let mut rng = StdRng::from_entropy();
     let f64_range = Uniform::new(0x0000_0000_0000_0001u64, 0x7ff0_0000_0000_0000);
     iterate("f64_random_equivalence_test", k, n, f, g, |_| {
         let x = f64::from_bits(f64_range.sample(&mut rng));

src/libcore/tests/slice.rs

@@ -1157,7 +1157,7 @@ fn test_rotate_right() {
 fn sort_unstable() {
     use core::cmp::Ordering::{Equal, Greater, Less};
     use core::slice::heapsort;
-    use rand::{FromEntropy, Rng, rngs::SmallRng, seq::SliceRandom};
+    use rand::{SeedableRng, Rng, rngs::StdRng, seq::SliceRandom};
 
     #[cfg(not(miri))] // Miri is too slow
     let large_range = 500..510;
@@ -1171,7 +1171,7 @@ fn sort_unstable() {
 
     let mut v = [0; 600];
     let mut tmp = [0; 600];
-    let mut rng = SmallRng::from_entropy();
+    let mut rng = StdRng::from_entropy();
 
     for len in (2..25).chain(large_range) {
         let v = &mut v[0..len];
@@ -1237,11 +1237,11 @@ fn sort_unstable() {
 #[cfg(not(miri))] // Miri is too slow
 fn partition_at_index() {
     use core::cmp::Ordering::{Equal, Greater, Less};
-    use rand::rngs::SmallRng;
+    use rand::rngs::StdRng;
     use rand::seq::SliceRandom;
-    use rand::{FromEntropy, Rng};
+    use rand::{SeedableRng, Rng};
 
-    let mut rng = SmallRng::from_entropy();
+    let mut rng = StdRng::from_entropy();
 
     for len in (2..21).chain(500..501) {
         let mut orig = vec![0; len];