Auto merge of #68360 - Dylan-DPC:rollup-iej35pz, r=Dylan-DPC

Rollup of 5 pull requests

Successful merges:

 - #67682 ([const-prop] Remove useless typedef)
 - #68133 (Slimmer syntax)
 - #68154 (Add more BTreeMap/BTreeSet benchmarks regarding iteration)
 - #68247 (Clean up err codes)
 - #68348 (Make iter::Empty<T> Send and Sync for any T)

Failed merges:

 - #68353 (Remove `rustc_error_codes` deps except in `rustc_driver`)

r? @ghost

Cargo.lock

@@ -3091,6 +3091,7 @@ dependencies = [
  "rustc-rayon",
  "rustc-rayon-core",
  "rustc_apfloat",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3357,6 +3358,7 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc",
+ "rustc_ast_pretty",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3374,6 +3376,8 @@ name = "rustc_ast_passes"
 version = "0.0.0"
 dependencies = [
  "log",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3384,12 +3388,41 @@ dependencies = [
  "syntax",
 ]
 
+[[package]]
+name = "rustc_ast_pretty"
+version = "0.0.0"
+dependencies = [
+ "log",
+ "rustc_data_structures",
+ "rustc_span",
+ "syntax",
+]
+
+[[package]]
+name = "rustc_attr"
+version = "0.0.0"
+dependencies = [
+ "rustc_ast_pretty",
+ "rustc_data_structures",
+ "rustc_error_codes",
+ "rustc_errors",
+ "rustc_feature",
+ "rustc_macros",
+ "rustc_session",
+ "rustc_span",
+ "serialize",
+ "smallvec 1.0.0",
+ "syntax",
+]
+
 [[package]]
 name = "rustc_builtin_macros"
 version = "0.0.0"
 dependencies = [
  "fmt_macros",
  "log",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3413,6 +3446,7 @@ dependencies = [
  "log",
  "rustc",
  "rustc-demangle",
+ "rustc_attr",
  "rustc_codegen_ssa",
  "rustc_codegen_utils",
  "rustc_data_structures",
@@ -3443,6 +3477,7 @@ dependencies = [
  "num_cpus",
  "rustc",
  "rustc_apfloat",
+ "rustc_attr",
  "rustc_codegen_utils",
  "rustc_data_structures",
  "rustc_error_codes",
@@ -3508,6 +3543,7 @@ dependencies = [
  "lazy_static 1.3.0",
  "log",
  "rustc",
+ "rustc_ast_pretty",
  "rustc_codegen_utils",
  "rustc_data_structures",
  "rustc_error_codes",
@@ -3554,6 +3590,8 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc_ast_passes",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_feature",
@@ -3583,11 +3621,11 @@ version = "0.0.0"
 name = "rustc_hir"
 version = "0.0.0"
 dependencies = [
+ "rustc_ast_pretty",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_index",
  "rustc_macros",
- "rustc_session",
  "rustc_span",
  "rustc_target",
  "serialize",
@@ -3630,6 +3668,7 @@ dependencies = [
  "rustc-rayon",
  "rustc_ast_lowering",
  "rustc_ast_passes",
+ "rustc_attr",
  "rustc_builtin_macros",
  "rustc_codegen_llvm",
  "rustc_codegen_ssa",
@@ -3674,6 +3713,8 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3715,6 +3756,8 @@ dependencies = [
  "log",
  "memmap",
  "rustc",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3743,6 +3786,8 @@ dependencies = [
  "polonius-engine",
  "rustc",
  "rustc_apfloat",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3766,6 +3811,7 @@ dependencies = [
  "log",
  "rustc",
  "rustc_apfloat",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3785,6 +3831,8 @@ version = "0.0.0"
 dependencies = [
  "bitflags",
  "log",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3803,6 +3851,7 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3835,6 +3884,7 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3853,6 +3903,8 @@ dependencies = [
  "log",
  "rustc",
  "rustc_ast_lowering",
+ "rustc_ast_pretty",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3874,6 +3926,7 @@ dependencies = [
  "rls-data",
  "rls-span",
  "rustc",
+ "rustc_ast_pretty",
  "rustc_codegen_utils",
  "rustc_data_structures",
  "rustc_hir",
@@ -3898,6 +3951,7 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "serialize",
+ "syntax",
 ]
 
 [[package]]
@@ -3972,6 +4026,7 @@ dependencies = [
  "arena",
  "log",
  "rustc",
+ "rustc_attr",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -4493,13 +4548,9 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc_data_structures",
- "rustc_error_codes",
- "rustc_errors",
- "rustc_feature",
  "rustc_index",
  "rustc_lexer",
  "rustc_macros",
- "rustc_session",
  "rustc_span",
  "scoped-tls",
  "serialize",

src/liballoc/benches/btree/map.rs

@@ -146,6 +146,36 @@ pub fn iter_100000(b: &mut Bencher) {
     bench_iter(b, 100000);
 }
 
+fn bench_iter_mut(b: &mut Bencher, size: i32) {
+    let mut map = BTreeMap::<i32, i32>::new();
+    let mut rng = thread_rng();
+
+    for _ in 0..size {
+        map.insert(rng.gen(), rng.gen());
+    }
+
+    b.iter(|| {
+        for kv in map.iter_mut() {
+            black_box(kv);
+        }
+    });
+}
+
+#[bench]
+pub fn iter_mut_20(b: &mut Bencher) {
+    bench_iter_mut(b, 20);
+}
+
+#[bench]
+pub fn iter_mut_1000(b: &mut Bencher) {
+    bench_iter_mut(b, 1000);
+}
+
+#[bench]
+pub fn iter_mut_100000(b: &mut Bencher) {
+    bench_iter_mut(b, 100000);
+}
+
 fn bench_first_and_last(b: &mut Bencher, size: i32) {
     let map: BTreeMap<_, _> = (0..size).map(|i| (i, i)).collect();
     b.iter(|| {

src/liballoc/benches/btree/set.rs

@@ -14,19 +14,13 @@ fn random(n: usize) -> BTreeSet<usize> {
 }
 
 fn neg(n: usize) -> BTreeSet<i32> {
-    let mut set = BTreeSet::new();
-    for i in -(n as i32)..=-1 {
-        set.insert(i);
-    }
+    let set: BTreeSet<i32> = (-(n as i32)..=-1).collect();
     assert_eq!(set.len(), n);
     set
 }
 
 fn pos(n: usize) -> BTreeSet<i32> {
-    let mut set = BTreeSet::new();
-    for i in 1..=(n as i32) {
-        set.insert(i);
-    }
+    let set: BTreeSet<i32> = (1..=(n as i32)).collect();
     assert_eq!(set.len(), n);
     set
 }
@@ -56,6 +50,43 @@ macro_rules! set_bench {
     };
 }
 
+const BUILD_SET_SIZE: usize = 100;
+
+#[bench]
+pub fn build_and_clear(b: &mut Bencher) {
+    b.iter(|| pos(BUILD_SET_SIZE).clear())
+}
+
+#[bench]
+pub fn build_and_drop(b: &mut Bencher) {
+    b.iter(|| pos(BUILD_SET_SIZE))
+}
+
+#[bench]
+pub fn build_and_into_iter(b: &mut Bencher) {
+    b.iter(|| pos(BUILD_SET_SIZE).into_iter().count())
+}
+
+#[bench]
+pub fn build_and_pop_all(b: &mut Bencher) {
+    b.iter(|| {
+        let mut s = pos(BUILD_SET_SIZE);
+        while s.pop_first().is_some() {}
+        s
+    });
+}
+
+#[bench]
+pub fn build_and_remove_all(b: &mut Bencher) {
+    b.iter(|| {
+        let mut s = pos(BUILD_SET_SIZE);
+        while let Some(elt) = s.iter().copied().next() {
+            s.remove(&elt);
+        }
+        s
+    });
+}
+
 set_bench! {intersection_100_neg_vs_100_pos, intersection, count, [neg(100), pos(100)]}
 set_bench! {intersection_100_neg_vs_10k_pos, intersection, count, [neg(100), pos(10_000)]}
 set_bench! {intersection_100_pos_vs_100_neg, intersection, count, [pos(100), neg(100)]}

src/libcore/iter/sources.rs

@@ -208,6 +208,11 @@ pub fn repeat_with<A, F: FnMut() -> A>(repeater: F) -> RepeatWith<F> {
 #[stable(feature = "iter_empty", since = "1.2.0")]
 pub struct Empty<T>(marker::PhantomData<T>);
 
+#[stable(feature = "iter_empty_send_sync", since = "1.42.0")]
+unsafe impl<T> Send for Empty<T> {}
+#[stable(feature = "iter_empty_send_sync", since = "1.42.0")]
+unsafe impl<T> Sync for Empty<T> {}
+
 #[stable(feature = "core_impl_debug", since = "1.9.0")]
 impl<T> fmt::Debug for Empty<T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

src/librustc/Cargo.toml

@@ -21,6 +21,7 @@ rustc-rayon = "0.3.0"
 rustc-rayon-core = "0.3.0"
 polonius-engine = "0.11.0"
 rustc_apfloat = { path = "../librustc_apfloat" }
+rustc_attr = { path = "../librustc_attr" }
 rustc_feature = { path = "../librustc_feature" }
 rustc_hir = { path = "../librustc_hir" }
 rustc_target = { path = "../librustc_target" }

src/librustc/hir/map/definitions.rs

@@ -10,12 +10,12 @@ use rustc_data_structures::stable_hasher::StableHasher;
 use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_index::vec::IndexVec;
-use rustc_session::node_id::NodeMap;
 use rustc_session::CrateDisambiguator;
 use rustc_span::hygiene::ExpnId;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 use syntax::ast;
+use syntax::node_id::NodeMap;
 
 use std::borrow::Borrow;
 use std::fmt::Write;

src/librustc/ich/impls_hir.rs

@@ -3,12 +3,12 @@
 
 use crate::hir::map::DefPathHash;
 use crate::ich::{Fingerprint, NodeIdHashingMode, StableHashingContext};
+use rustc_attr as attr;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
 use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX};
 use smallvec::SmallVec;
 use std::mem;
-use syntax::attr;
 
 impl<'ctx> rustc_hir::HashStableContext for StableHashingContext<'ctx> {
     #[inline]

src/librustc/middle/codegen_fn_attrs.rs

@@ -1,6 +1,6 @@
 use crate::mir::mono::Linkage;
+use rustc_attr::{InlineAttr, OptimizeAttr};
 use rustc_span::symbol::Symbol;
-use syntax::attr::{InlineAttr, OptimizeAttr};
 
 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
 pub struct CodegenFnAttrs {