Use ArrayVec instead of SmallVec

Author: bugadani

Cargo.lock

@@ -4386,6 +4386,7 @@ dependencies = [
 name = "rustdoc"
 version = "0.0.0"
 dependencies = [
+ "arrayvec",
  "expect-test",
  "itertools 0.9.0",
  "minifier",

src/librustdoc/Cargo.toml

@@ -8,6 +8,7 @@ edition = "2018"
 path = "lib.rs"
 
 [dependencies]
+arrayvec = { version = "0.5.1", default-features = false }
 pulldown-cmark = { version = "0.8", default-features = false }
 minifier = "0.0.33"
 rayon = { version = "0.3.0", package = "rustc-rayon" }

src/librustdoc/clean/types.rs

@@ -8,6 +8,7 @@ use std::rc::Rc;
 use std::sync::Arc;
 use std::{slice, vec};
 
+use arrayvec::ArrayVec;
 use rustc_ast::attr;
 use rustc_ast::util::comments::beautify_doc_string;
 use rustc_ast::{self as ast, AttrStyle};
@@ -28,7 +29,6 @@ use rustc_span::symbol::{kw, sym, Ident, Symbol, SymbolStr};
 use rustc_span::{self, FileName, Loc};
 use rustc_target::abi::VariantIdx;
 use rustc_target::spec::abi::Abi;
-use smallvec::{smallvec, SmallVec};
 
 use crate::clean::cfg::Cfg;
 use crate::clean::external_path;
@@ -1539,12 +1539,12 @@ impl PrimitiveType {
         }
     }
 
-    crate fn impls(&self, tcx: TyCtxt<'_>) -> &'static SmallVec<[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, SmallVec<[DefId; 4]>> {
-        static CELL: OnceCell<FxHashMap<PrimitiveType, SmallVec<[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::*;
@@ -1568,7 +1568,7 @@ impl PrimitiveType {
             }
 
             let single = |a: Option<DefId>| a.into_iter().collect();
-            let both = |a: Option<DefId>, b: Option<DefId>| -> SmallVec<_> {
+            let both = |a: Option<DefId>, b: Option<DefId>| -> ArrayVec<_> {
                 a.into_iter().chain(b).collect()
             };
 
@@ -1601,8 +1601,8 @@ impl PrimitiveType {
                         .collect()
                 },
                 Array => single(lang_items.array_impl()),
-                Tuple => smallvec![],
-                Unit => smallvec![],
+                Tuple => ArrayVec::new(),
+                Unit => ArrayVec::new(),
                 RawPointer => {
                     lang_items
                         .const_ptr_impl()
@@ -1612,9 +1612,9 @@ impl PrimitiveType {
                         .chain(lang_items.mut_slice_ptr_impl())
                         .collect()
                 },
-                Reference => smallvec![],
-                Fn => smallvec![],
-                Never => smallvec![],
+                Reference => ArrayVec::new(),
+                Fn => ArrayVec::new(),
+                Never => ArrayVec::new(),
             }
         })
     }