.github/workflows/main.yml

@@ -2,7 +2,7 @@ name: CI
 
 on:
   push:
-    branches: [auto]
+    branches: [v2]
   pull_request:
   workflow_dispatch:
 
@@ -12,26 +12,23 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        toolchain: ["stable", "beta", "nightly", "1.36.0"]
+        toolchain: ["stable", "beta", "nightly", "1.57.0"]
         include:
           - toolchain: stable
-            env:
-              DO_FUZZ: 1
+            fuzz: 1
           - toolchain: beta
-            env:
-              DO_FUZZ: 1
+            fuzz: 1
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
-      - name: Install packages
-        run: sudo apt-get install -y binutils-dev libunwind8-dev libcurl4-openssl-dev libelf-dev libdw-dev cmake gcc libiberty-dev
+      - name: Install packages for fuzzing
+        if: runner.os == 'Linux' && matrix.fuzz == 1
+        run: sudo apt-get update -y && sudo apt-get install -y binutils-dev libunwind8-dev libcurl4-openssl-dev libelf-dev libdw-dev cmake gcc libiberty-dev
 
       - name: Install toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@master
         with:
-          profile: minimal
           toolchain: ${{ matrix.toolchain }}
-          override: true
 
       - name: Cargo build
         run: cargo build --verbose
@@ -46,10 +43,6 @@ jobs:
         if: matrix.toolchain == 'nightly'
         run: cargo check --verbose --no-default-features
 
-      - name: Cargo test w/ union
-        if: matrix.toolchain == 'beta'
-        run: cargo test --verbose --features union
-
       - name: Cargo test all features
         if: matrix.toolchain == 'nightly'
         run: cargo test --verbose --all-features
@@ -61,19 +54,31 @@ jobs:
       - name: miri
         if: matrix.toolchain == 'nightly'
         run: bash ./scripts/run_miri.sh
-        env:
-          MIRIFLAGS: '-Zmiri-tag-raw-pointers'
 
       - name: fuzz
-        if: env.DO_FUZZ == '1'
+        if: matrix.fuzz == 1
         working-directory: fuzz
-        run: ./travis_fuzz.sh
+        run: ./travis-fuzz.sh
+
+  no-std:
+    name: no_std
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install toolchain
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: stable
+          target: thumbv7m-none-eabi
+      - name: Cargo build
+        run: cargo build --verbose
 
   build_result:
     name: homu build finished
     runs-on: ubuntu-latest
     needs:
       - "linux-ci"
+      - "no-std"
 
     steps:
       - name: Mark the job as successful

.gitignore

@@ -1,3 +1,4 @@
 target
-/Cargo.lock
+Cargo.lock
 /fuzz/hfuzz_target
+/.vscode

Cargo.toml

@@ -1,7 +1,8 @@
 [package]
 name = "smallvec"
-version = "1.9.0"
-edition = "2018"
+version = "2.0.0-alpha.10"
+edition = "2021"
+rust-version = "1.57"
 authors = ["The Servo Project Developers"]
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/servo/rust-smallvec"
@@ -12,18 +13,15 @@ readme = "README.md"
 documentation = "https://docs.rs/smallvec/"
 
 [features]
-const_generics = []
-const_new = ["const_generics"]
-write = []
-union = []
+std = []
 specialization = []
 may_dangle = []
+extract_if = []
 
 [dependencies]
 serde = { version = "1", optional = true, default-features = false }
-arbitrary = { version = "1", optional = true }
 
-[dev_dependencies]
+[dev-dependencies]
 bincode = "1.0.1"
 
 [package.metadata.docs.rs]

README.md

@@ -1,6 +1,21 @@
 rust-smallvec
 =============
 
+> **⚠️ Note:**
+> This is the code for smallvec 2.0, which is not yet ready for release.  For
+> details about the changes in version 2.0, please see [#183], [#240], and [#284].
+>
+> The source code for the latest smallvec 1.x.y release can be found on the
+> [v1 branch].  Bug fixes for smallvec 1 should be based on that branch, while
+> new feature development should go on the v2 branch.
+
+[v1 branch]: https://github.com/servo/rust-smallvec/tree/v1
+[#183]: https://github.com/servo/rust-smallvec/issues/183
+[#240]: https://github.com/servo/rust-smallvec/issues/240
+[#284]: https://github.com/servo/rust-smallvec/issues/284
+
+## About smallvec
+
 [Documentation](https://docs.rs/smallvec/)
 
 [Release notes](https://github.com/servo/rust-smallvec/releases)
@@ -13,7 +28,7 @@ rust-smallvec
 use smallvec::{SmallVec, smallvec};
 
 // This SmallVec can hold up to 4 items on the stack:
-let mut v: SmallVec<[i32; 4]> = smallvec![1, 2, 3, 4];
+let mut v: SmallVec<i32, 4> = smallvec![1, 2, 3, 4];
 
 // It will automatically move its contents to the heap if
 // contains more than four items:

benches/bench.rs

@@ -1,24 +1,23 @@
 #![feature(test)]
 #![allow(deprecated)]
 
-#[macro_use]
-extern crate smallvec;
 extern crate test;
 
-use self::test::Bencher;
-use smallvec::{ExtendFromSlice, SmallVec};
+use smallvec::{smallvec, SmallVec};
+use test::Bencher;
 
 const VEC_SIZE: usize = 16;
 const SPILLED_SIZE: usize = 100;
 
-trait Vector<T>: for<'a> From<&'a [T]> + Extend<T> + ExtendFromSlice<T> {
+trait Vector<T>: for<'a> From<&'a [T]> + Extend<T> {
     fn new() -> Self;
     fn push(&mut self, val: T);
     fn pop(&mut self) -> Option<T>;
     fn remove(&mut self, p: usize) -> T;
     fn insert(&mut self, n: usize, val: T);
     fn from_elem(val: T, n: usize) -> Self;
     fn from_elems(val: &[T]) -> Self;
+    fn extend_from_slice(&mut self, other: &[T]);
 }
 
 impl<T: Copy> Vector<T> for Vec<T> {
@@ -49,9 +48,13 @@ impl<T: Copy> Vector<T> for Vec<T> {
     fn from_elems(val: &[T]) -> Self {
         val.to_owned()
     }
+
+    fn extend_from_slice(&mut self, other: &[T]) {
+        Vec::extend_from_slice(self, other)
+    }
 }
 
-impl<T: Copy> Vector<T> for SmallVec<[T; VEC_SIZE]> {
+impl<T: Copy> Vector<T> for SmallVec<T, VEC_SIZE> {
     fn new() -> Self {
         Self::new()
     }
@@ -79,6 +82,10 @@ impl<T: Copy> Vector<T> for SmallVec<[T; VEC_SIZE]> {
     fn from_elems(val: &[T]) -> Self {
         SmallVec::from_slice(val)
     }
+
+    fn extend_from_slice(&mut self, other: &[T]) {
+        SmallVec::extend_from_slice(self, other)
+    }
 }
 
 macro_rules! make_benches {
@@ -93,7 +100,7 @@ macro_rules! make_benches {
 }
 
 make_benches! {
-    SmallVec<[u64; VEC_SIZE]> {
+    SmallVec<u64, VEC_SIZE> {
         bench_push => gen_push(SPILLED_SIZE as _),
         bench_push_small => gen_push(VEC_SIZE as _),
         bench_insert_push => gen_insert_push(SPILLED_SIZE as _),
@@ -104,6 +111,8 @@ make_benches! {
         bench_remove_small => gen_remove(VEC_SIZE as _),
         bench_extend => gen_extend(SPILLED_SIZE as _),
         bench_extend_small => gen_extend(VEC_SIZE as _),
+        bench_extend_filtered => gen_extend_filtered(SPILLED_SIZE as _),
+        bench_extend_filtered_small => gen_extend_filtered(VEC_SIZE as _),
         bench_from_iter => gen_from_iter(SPILLED_SIZE as _),
         bench_from_iter_small => gen_from_iter(VEC_SIZE as _),
         bench_from_slice => gen_from_slice(SPILLED_SIZE as _),
@@ -128,6 +137,8 @@ make_benches! {
         bench_remove_vec_small => gen_remove(VEC_SIZE as _),
         bench_extend_vec => gen_extend(SPILLED_SIZE as _),
         bench_extend_vec_small => gen_extend(VEC_SIZE as _),
+        bench_extend_vec_filtered => gen_extend_filtered(SPILLED_SIZE as _),
+        bench_extend_vec_filtered_small => gen_extend_filtered(VEC_SIZE as _),
         bench_from_iter_vec => gen_from_iter(SPILLED_SIZE as _),
         bench_from_iter_vec_small => gen_from_iter(VEC_SIZE as _),
         bench_from_slice_vec => gen_from_slice(SPILLED_SIZE as _),
@@ -211,6 +222,14 @@ fn gen_extend<V: Vector<u64>>(n: u64, b: &mut Bencher) {
     });
 }
 
+fn gen_extend_filtered<V: Vector<u64>>(n: u64, b: &mut Bencher) {
+    b.iter(|| {
+        let mut vec = V::new();
+        vec.extend((0..n).filter(|i| i % 2 == 0));
+        vec
+    });
+}
+
 fn gen_from_iter<V: Vector<u64>>(n: u64, b: &mut Bencher) {
     let v: Vec<u64> = (0..n).collect();
     b.iter(|| {
@@ -263,15 +282,15 @@ fn gen_from_elem<V: Vector<u64>>(n: usize, b: &mut Bencher) {
 fn bench_insert_many(b: &mut Bencher) {
     #[inline(never)]
     fn insert_many_noinline<I: IntoIterator<Item = u64>>(
-        vec: &mut SmallVec<[u64; VEC_SIZE]>,
+        vec: &mut SmallVec<u64, VEC_SIZE>,
         index: usize,
         iterable: I,
     ) {
         vec.insert_many(index, iterable)
     }
 
     b.iter(|| {
-        let mut vec = SmallVec::<[u64; VEC_SIZE]>::new();
+        let mut vec = SmallVec::<u64, VEC_SIZE>::new();
         insert_many_noinline(&mut vec, 0, 0..SPILLED_SIZE as _);
         insert_many_noinline(&mut vec, 0, 0..SPILLED_SIZE as _);
         vec
@@ -282,7 +301,7 @@ fn bench_insert_many(b: &mut Bencher) {
 fn bench_insert_from_slice(b: &mut Bencher) {
     let v: Vec<u64> = (0..SPILLED_SIZE as _).collect();
     b.iter(|| {
-        let mut vec = SmallVec::<[u64; VEC_SIZE]>::new();
+        let mut vec = SmallVec::<u64, VEC_SIZE>::new();
         vec.insert_from_slice(0, &v);
         vec.insert_from_slice(0, &v);
         vec
@@ -292,7 +311,7 @@ fn bench_insert_from_slice(b: &mut Bencher) {
 #[bench]
 fn bench_macro_from_list(b: &mut Bencher) {
     b.iter(|| {
-        let vec: SmallVec<[u64; 16]> = smallvec![
+        let vec: SmallVec<u64, 16> = smallvec![
             0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 20, 24, 32, 36, 0x40, 0x80,
             0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000, 0x20000, 0x40000,
             0x80000, 0x100000,