Auto merge of #84420 - workingjubilee:microvec, r=Mark-Simulacrum

Use arrayvec 0.7, drop smallvec 0.6

With the arrival of min const generics, many alt-vec libraries have
updated to use it in some way and arrayvec is no exception. Use the
latest with minor refactoring.

Also, rustc_workspace_hack is the only user of smallvec 0.6 in the
entire tree, so drop it.

8 files changed, 61 insertions, 69 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 740bf7cc9ec..c51843440a3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -111,9 +111,15 @@ checksum = "a4c527152e37cf757a3f78aae5a06fbeefdb07ccc535c980a3208ee3060dd544"
 
 [[package]]
 name = "arrayvec"
-version = "0.5.1"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "23b62fc65de8e4e7f52534fb52b0f3ed04746ae267519eef2a83941e8085068b"
+
+[[package]]
+name = "arrayvec"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cff77d8686867eceff3105329d4698d96c2391c176d5d03adc90c7389162b5b8"
+checksum = "5a2f58b0bb10c380af2b26e57212856b8c9a59e0925b4c20f4a174a49734eaf7"
 
 [[package]]
 name = "atty"
@@ -160,7 +166,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d8fb2d74254a3a0b5cac33ac9f8ed0e44aa50378d9dbb2e5d83bd21ed1dc2c8a"
 dependencies = [
  "arrayref",
- "arrayvec",
+ "arrayvec 0.5.2",
  "constant_time_eq",
 ]
 
@@ -2165,7 +2171,7 @@ dependencies = [
  "parking_lot",
  "perf-event-open-sys",
  "rustc-hash",
- "smallvec 1.6.1",
+ "smallvec",
 ]
 
 [[package]]
@@ -2324,7 +2330,7 @@ dependencies = [
  "rustc-workspace-hack",
  "rustc_version",
  "shell-escape",
- "smallvec 1.6.1",
+ "smallvec",
 ]
 
 [[package]]
@@ -2548,7 +2554,7 @@ dependencies = [
  "instant",
  "libc",
  "redox_syscall 0.2.5",
- "smallvec 1.6.1",
+ "smallvec",
  "winapi 0.3.9",
 ]
 
@@ -3269,7 +3275,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "259cca0e975ecb05fd289ace45280c30ff792efc04e856a7f18b7fc86a3cb610"
 dependencies = [
  "rustc-ap-rustc_data_structures",
- "smallvec 1.6.1",
+ "smallvec",
 ]
 
 [[package]]
@@ -3285,7 +3291,7 @@ dependencies = [
  "rustc-ap-rustc_macros",
  "rustc-ap-rustc_serialize",
  "rustc-ap-rustc_span",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -3343,7 +3349,7 @@ version = "712.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9cbfa7f82517a1b2efe7106c864c3f930b1da8aff07a27fd317af2f36522fd2e"
 dependencies = [
- "arrayvec",
+ "arrayvec 0.5.2",
  "bitflags",
  "cfg-if 0.1.10",
  "crossbeam-utils 0.7.2",
@@ -3360,7 +3366,7 @@ dependencies = [
  "rustc-hash",
  "rustc-rayon",
  "rustc-rayon-core",
- "smallvec 1.6.1",
+ "smallvec",
  "stable_deref_trait",
  "stacker",
  "tempfile",
@@ -3408,7 +3414,7 @@ dependencies = [
  "rustc-ap-rustc_serialize",
  "rustc-ap-rustc_session",
  "rustc-ap-rustc_span",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -3440,7 +3446,7 @@ version = "712.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f6f53afc4f7111c82295cb7ea3878f520bbac6a2c5a12e125b4ca9156498cff"
 dependencies = [
- "arrayvec",
+ "arrayvec 0.5.2",
  "rustc-ap-rustc_macros",
  "rustc-ap-rustc_serialize",
 ]
@@ -3496,7 +3502,7 @@ dependencies = [
  "rustc-ap-rustc_lexer",
  "rustc-ap-rustc_session",
  "rustc-ap-rustc_span",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
  "unicode-normalization",
 ]
@@ -3508,7 +3514,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d33c710120953c0214f47a6caf42064d7e241003b4af36c98a6d6156e70335f1"
 dependencies = [
  "indexmap",
- "smallvec 1.6.1",
+ "smallvec",
 ]
 
 [[package]]
@@ -3657,8 +3663,7 @@ dependencies = [
  "quote",
  "serde",
  "serde_json",
- "smallvec 0.6.14",
- "smallvec 1.6.1",
+ "smallvec",
  "syn",
  "url 2.1.1",
  "winapi 0.3.9",
@@ -3669,7 +3674,7 @@ name = "rustc_apfloat"
 version = "0.0.0"
 dependencies = [
  "bitflags",
- "smallvec 1.6.1",
+ "smallvec",
 ]
 
 [[package]]
@@ -3677,7 +3682,7 @@ name = "rustc_arena"
 version = "0.0.0"
 dependencies = [
  "rustc_data_structures",
- "smallvec 1.6.1",
+ "smallvec",
 ]
 
 [[package]]
@@ -3691,7 +3696,7 @@ dependencies = [
  "rustc_macros",
  "rustc_serialize",
  "rustc_span",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -3709,7 +3714,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -3772,7 +3777,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -3801,7 +3806,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
- "smallvec 1.6.1",
+ "smallvec",
  "snap",
  "tracing",
 ]
@@ -3840,7 +3845,7 @@ dependencies = [
 name = "rustc_data_structures"
 version = "0.0.0"
 dependencies = [
- "arrayvec",
+ "arrayvec 0.7.0",
  "bitflags",
  "cfg-if 0.1.10",
  "crossbeam-utils 0.7.2",
@@ -3858,7 +3863,7 @@ dependencies = [
  "rustc_index",
  "rustc_macros",
  "rustc_serialize",
- "smallvec 1.6.1",
+ "smallvec",
  "stable_deref_trait",
  "stacker",
  "tempfile",
@@ -3941,7 +3946,7 @@ dependencies = [
  "rustc_serialize",
  "rustc_session",
  "rustc_span",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -3973,7 +3978,7 @@ dependencies = [
  "rustc_serialize",
  "rustc_span",
  "rustc_target",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -4010,7 +4015,7 @@ dependencies = [
 name = "rustc_index"
 version = "0.0.0"
 dependencies = [
- "arrayvec",
+ "arrayvec 0.7.0",
  "rustc_macros",
  "rustc_serialize",
 ]
@@ -4031,7 +4036,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -4075,7 +4080,7 @@ dependencies = [
  "rustc_traits",
  "rustc_ty_utils",
  "rustc_typeck",
- "smallvec 1.6.1",
+ "smallvec",
  "tempfile",
  "tracing",
  "winapi 0.3.9",
@@ -4164,7 +4169,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
- "smallvec 1.6.1",
+ "smallvec",
  "snap",
  "stable_deref_trait",
  "tracing",
@@ -4196,7 +4201,7 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "rustc_type_ir",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -4227,7 +4232,7 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "rustc_trait_selection",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -4250,7 +4255,7 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "rustc_trait_selection",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -4267,7 +4272,7 @@ dependencies = [
  "rustc_lexer",
  "rustc_session",
  "rustc_span",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
  "unicode-normalization",
 ]
@@ -4368,7 +4373,7 @@ dependencies = [
  "rustc_serialize",
  "rustc_session",
  "rustc_span",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -4392,7 +4397,7 @@ dependencies = [
  "rustc_middle",
  "rustc_session",
  "rustc_span",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -4421,7 +4426,7 @@ version = "0.0.0"
 dependencies = [
  "indexmap",
  "rustc_macros",
- "smallvec 1.6.1",
+ "smallvec",
 ]
 
 [[package]]
@@ -4518,7 +4523,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -4538,7 +4543,7 @@ dependencies = [
  "rustc_middle",
  "rustc_span",
  "rustc_trait_selection",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -4588,7 +4593,7 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "rustc_trait_selection",
- "smallvec 1.6.1",
+ "smallvec",
  "tracing",
 ]
 
@@ -4605,7 +4610,7 @@ dependencies = [
 name = "rustdoc"
 version = "0.0.0"
 dependencies = [
- "arrayvec",
+ "arrayvec 0.7.0",
  "expect-test",
  "itertools 0.9.0",
  "minifier",
@@ -4615,7 +4620,7 @@ dependencies = [
  "rustdoc-json-types",
  "serde",
  "serde_json",
- "smallvec 1.6.1",
+ "smallvec",
  "tempfile",
  "tracing",
  "tracing-subscriber",
@@ -4963,15 +4968,6 @@ checksum = "c111b5bd5695e56cffe5129854aa230b39c93a305372fdbb2668ca2394eea9f8"
 
 [[package]]
 name = "smallvec"
-version = "0.6.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b97fcaeba89edba30f044a10c6a3cc39df9c3f17d7cd829dd1446cab35f890e0"
-dependencies = [
- "maybe-uninit",
-]
-
-[[package]]
-name = "smallvec"
 version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fe0f37c9e8f3c5a4a66ad655a93c74daac4ad00c441533bf5c6e7990bb42604e"
@@ -5489,7 +5485,7 @@ dependencies = [
  "serde",
  "serde_json",
  "sharded-slab",
- "smallvec 1.6.1",
+ "smallvec",
  "thread_local",
  "tracing",
  "tracing-core",
diff --git a/compiler/rustc_data_structures/Cargo.toml b/compiler/rustc_data_structures/Cargo.toml
index d32598e716e..d0a5fe1f2a6 100644
--- a/compiler/rustc_data_structures/Cargo.toml
+++ b/compiler/rustc_data_structures/Cargo.toml
@@ -8,7 +8,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-arrayvec = { version = "0.5.1", default-features = false }
+arrayvec = { version = "0.7", default-features = false }
 ena = "0.14"
 indexmap = "1.5.1"
 tracing = "0.1"
diff --git a/compiler/rustc_data_structures/src/sso/map.rs b/compiler/rustc_data_structures/src/sso/map.rs
index 06e8442d475..e249886e9bc 100644
--- a/compiler/rustc_data_structures/src/sso/map.rs
+++ b/compiler/rustc_data_structures/src/sso/map.rs
@@ -18,11 +18,8 @@ use std::ops::Index;
 // for reasonably small arrays that stay
 // small in vast majority of cases.
 //
-// '8' is choosen as a sane default, to be
+// '8' is chosen as a sane default, to be
 // reevaluated later.
-//
-// Note: As of now ArrayVec design prevents
-//       us from making it user-customizable.
 const SSO_ARRAY_SIZE: usize = 8;
 
 /// Small-storage-optimized implementation of a map.
@@ -70,7 +67,7 @@ const SSO_ARRAY_SIZE: usize = 8;
 
 #[derive(Clone)]
 pub enum SsoHashMap<K, V> {
-    Array(ArrayVec<[(K, V); SSO_ARRAY_SIZE]>),
+    Array(ArrayVec<(K, V), SSO_ARRAY_SIZE>),
     Map(FxHashMap<K, V>),
 }
 
@@ -411,7 +408,7 @@ where
 
 impl<K, V> IntoIterator for SsoHashMap<K, V> {
     type IntoIter = EitherIter<
-        <ArrayVec<[(K, V); 8]> as IntoIterator>::IntoIter,
+        <ArrayVec<(K, V), 8> as IntoIterator>::IntoIter,
         <FxHashMap<K, V> as IntoIterator>::IntoIter,
     >;
     type Item = <Self::IntoIter as Iterator>::Item;
@@ -441,7 +438,7 @@ fn adapt_array_mut_it<K, V>(pair: &'a mut (K, V)) -> (&'a K, &'a mut V) {
 impl<'a, K, V> IntoIterator for &'a SsoHashMap<K, V> {
     type IntoIter = EitherIter<
         std::iter::Map<
-            <&'a ArrayVec<[(K, V); 8]> as IntoIterator>::IntoIter,
+            <&'a ArrayVec<(K, V), 8> as IntoIterator>::IntoIter,
             fn(&'a (K, V)) -> (&'a K, &'a V),
         >,
         <&'a FxHashMap<K, V> as IntoIterator>::IntoIter,
@@ -459,7 +456,7 @@ impl<'a, K, V> IntoIterator for &'a SsoHashMap<K, V> {
 impl<'a, K, V> IntoIterator for &'a mut SsoHashMap<K, V> {
     type IntoIter = EitherIter<
         std::iter::Map<
-            <&'a mut ArrayVec<[(K, V); 8]> as IntoIterator>::IntoIter,
+            <&'a mut ArrayVec<(K, V), 8> as IntoIterator>::IntoIter,
             fn(&'a mut (K, V)) -> (&'a K, &'a mut V),
         >,
         <&'a mut FxHashMap<K, V> as IntoIterator>::IntoIter,
diff --git a/compiler/rustc_index/Cargo.toml b/compiler/rustc_index/Cargo.toml
index 6e1471df195..4b1f0b86475 100644
--- a/compiler/rustc_index/Cargo.toml
+++ b/compiler/rustc_index/Cargo.toml
@@ -8,6 +8,6 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-arrayvec = { version = "0.5.1", default-features = false }
+arrayvec = { version = "0.7", default-features = false }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_macros = { path = "../rustc_macros" }
diff --git a/compiler/rustc_index/src/bit_set.rs b/compiler/rustc_index/src/bit_set.rs
index cfea5092bc3..d26ab1939e3 100644
--- a/compiler/rustc_index/src/bit_set.rs
+++ b/compiler/rustc_index/src/bit_set.rs
@@ -375,7 +375,7 @@ const SPARSE_MAX: usize = 8;
 #[derive(Clone, Debug)]
 pub struct SparseBitSet<T> {
     domain_size: usize,
-    elems: ArrayVec<[T; SPARSE_MAX]>,
+    elems: ArrayVec<T, SPARSE_MAX>,
 }
 
 impl<T: Idx> SparseBitSet<T> {
diff --git a/src/librustdoc/Cargo.toml b/src/librustdoc/Cargo.toml
index d778a507425..b816b9d7188 100644
--- a/src/librustdoc/Cargo.toml
+++ b/src/librustdoc/Cargo.toml
@@ -8,7 +8,7 @@ edition = "2018"
 path = "lib.rs"
 
 [dependencies]
-arrayvec = { version = "0.5.1", default-features = false }
+arrayvec = { version = "0.7", default-features = false }
 pulldown-cmark = { version = "0.8", default-features = false }
 minifier = "0.0.39"
 rayon = { version = "0.3.0", package = "rustc-rayon" }
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 2b25c6a26bc..675de640c70 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -1616,18 +1616,18 @@ impl PrimitiveType {
         }
     }
 
-    crate fn impls(&self, tcx: TyCtxt<'_>) -> &'static ArrayVec<[DefId; 4]> {
+    crate fn impls(&self, tcx: TyCtxt<'_>) -> &'static ArrayVec<DefId, 4> {
         Self::all_impls(tcx).get(self).expect("missing impl for primitive type")
     }
 
-    crate fn all_impls(tcx: TyCtxt<'_>) -> &'static FxHashMap<PrimitiveType, ArrayVec<[DefId; 4]>> {
-        static CELL: OnceCell<FxHashMap<PrimitiveType, ArrayVec<[DefId; 4]>>> = OnceCell::new();
+    crate fn all_impls(tcx: TyCtxt<'_>) -> &'static FxHashMap<PrimitiveType, ArrayVec<DefId, 4>> {
+        static CELL: OnceCell<FxHashMap<PrimitiveType, ArrayVec<DefId, 4>>> = OnceCell::new();
 
         CELL.get_or_init(move || {
             use self::PrimitiveType::*;
 
             let single = |a: Option<DefId>| a.into_iter().collect();
-            let both = |a: Option<DefId>, b: Option<DefId>| -> ArrayVec<_> {
+            let both = |a: Option<DefId>, b: Option<DefId>| -> ArrayVec<_, 4> {
                 a.into_iter().chain(b).collect()
             };
 
diff --git a/src/tools/rustc-workspace-hack/Cargo.toml b/src/tools/rustc-workspace-hack/Cargo.toml
index 8da7db2dfdd..5776d56d187 100644
--- a/src/tools/rustc-workspace-hack/Cargo.toml
+++ b/src/tools/rustc-workspace-hack/Cargo.toml
@@ -71,7 +71,6 @@ proc-macro2 = { version = "1", features = ["default"] }
 quote = { version = "1", features = ["default"] }
 serde = { version = "1.0.82", features = ['derive'] }
 serde_json = { version = "1.0.31", features = ["raw_value", "unbounded_depth"] }
-smallvec-0_6 = { package = "smallvec", version = "0.6.14", features = ['union', 'may_dangle'] }
 smallvec = { version = "1.6.1", features = ['union', 'may_dangle'] }
 syn = { version = "1", features = ['fold', 'full', 'extra-traits', 'visit', 'visit-mut'] }
 url = { version = "2.0", features = ['serde'] }