Auto merge of #118769 - pitaj:range-experiment, r=<try>

Range experiment

Meant for a crater run to see how much breakage we can expect outside of the Iterator methods themselves

https://internals.rust-lang.org/t/pre-rfc-fixing-range-by-2027/19936

Author: bors

Cargo.lock

@@ -3006,9 +3006,9 @@ checksum = "dc375e1527247fe1a97d8b7156678dfe7c1af2fc075c9a4db3690ecd2a148068"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.63"
+version = "1.0.70"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b368fba921b0dce7e60f5e04ec15e565b3303972b42bcfde1d0713b881959eb"
+checksum = "39278fbbf5fb4f646ce651690877f89d1c5811a3d4acb27700c1cb3cdb78fd3b"
 dependencies = [
  "unicode-ident",
 ]
@@ -3064,9 +3064,8 @@ checksum = "07589615d719a60c8dd8a4622e7946465dfef20d1a428f969e3443e7386d5f45"
 
 [[package]]
 name = "quote"
-version = "1.0.29"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "573015e8ab27661678357f27dc26460738fd2b6c86e46f386fde94cb5d913105"
+version = "1.0.33"
+source = "git+https://github.com/pitaj/quote#44feebf0594b255a511ff20890a7acbf4d6aeed1"
 dependencies = [
  "proc-macro2",
 ]
@@ -3349,11 +3348,10 @@ dependencies = [
 [[package]]
 name = "rustc-rayon"
 version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eb81aadc8837ca6ecebe0fe1353f15df83b3b3cc2cf7a8afd571bc22aa121710"
+source = "git+https://github.com/pitaj/rustc-rayon#e76e554512ce25abb48f4118576ede5d7a457918"
 dependencies = [
  "either",
- "rustc-rayon-core",
+ "rustc-rayon-core 0.5.0 (git+https://github.com/pitaj/rustc-rayon)",
 ]
 
 [[package]]
@@ -3368,6 +3366,17 @@ dependencies = [
  "num_cpus",
 ]
 
+[[package]]
+name = "rustc-rayon-core"
+version = "0.5.0"
+source = "git+https://github.com/pitaj/rustc-rayon#e76e554512ce25abb48f4118576ede5d7a457918"
+dependencies = [
+ "crossbeam-channel",
+ "crossbeam-deque",
+ "crossbeam-utils",
+ "num_cpus",
+]
+
 [[package]]
 name = "rustc-semver"
 version = "1.1.0"
@@ -3697,7 +3706,7 @@ dependencies = [
  "portable-atomic",
  "rustc-hash",
  "rustc-rayon",
- "rustc-rayon-core",
+ "rustc-rayon-core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_arena",
  "rustc_graphviz",
  "rustc_index",
@@ -4023,7 +4032,7 @@ version = "0.0.0"
 dependencies = [
  "libloading 0.7.4",
  "rustc-rayon",
- "rustc-rayon-core",
+ "rustc-rayon-core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_ast",
  "rustc_ast_lowering",
  "rustc_ast_passes",
@@ -4188,7 +4197,7 @@ dependencies = [
  "measureme",
  "polonius-engine",
  "rustc-rayon",
- "rustc-rayon-core",
+ "rustc-rayon-core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_apfloat",
  "rustc_arena",
  "rustc_ast",
@@ -4388,7 +4397,7 @@ version = "0.0.0"
 dependencies = [
  "field-offset",
  "measureme",
- "rustc-rayon-core",
+ "rustc-rayon-core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hir",
@@ -4407,7 +4416,7 @@ name = "rustc_query_system"
 version = "0.0.0"
 dependencies = [
  "parking_lot 0.12.1",
- "rustc-rayon-core",
+ "rustc-rayon-core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_ast",
  "rustc_data_structures",
  "rustc_errors",

Cargo.toml

@@ -111,5 +111,8 @@ rustc-std-workspace-core = { path = 'library/rustc-std-workspace-core' }
 rustc-std-workspace-alloc = { path = 'library/rustc-std-workspace-alloc' }
 rustc-std-workspace-std = { path = 'library/rustc-std-workspace-std' }
 
+rustc-rayon = { git = "https://github.com/pitaj/rustc-rayon" }
+quote = { git = "https://github.com/pitaj/quote" }
+
 [patch."https://github.com/rust-lang/rust-clippy"]
 clippy_lints = { path = "src/tools/clippy/clippy_lints" }

compiler/rustc_borrowck/src/borrow_set.rs

@@ -161,7 +161,7 @@ impl<'tcx> BorrowSet<'tcx> {
     }
 
     pub(crate) fn indices(&self) -> impl Iterator<Item = BorrowIndex> {
-        BorrowIndex::from_usize(0)..BorrowIndex::from_usize(self.len())
+        (BorrowIndex::from_usize(0)..BorrowIndex::from_usize(self.len())).into_iter()
     }
 
     pub(crate) fn iter_enumerated(&self) -> impl Iterator<Item = (BorrowIndex, &BorrowData<'tcx>)> {

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -2140,7 +2140,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         // we still want to screen for an "interesting" point to
         // highlight (e.g., a call site or something).
         let target_scc = self.constraint_sccs.scc(target_region);
-        let mut range = 0..path.len();
+        let mut range = (0..path.len()).into_iter();
 
         // As noted above, when reporting an error, there is typically a chain of constraints
         // leading from some "source" region which must outlive some "target" region.

compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs

@@ -28,7 +28,7 @@ pub fn expand_deriving_partial_ord(
             // No data, placing the tag check first makes codegen simpler
             0 => true,
             1..=2 => false,
-            _ => (0..dataful.len() - 1).any(|i| {
+            _ => (0..dataful.len() - 1).into_iter().any(|i| {
                 if dataful[i]
                     && let Some(idx) = dataful[i + 1..].iter().position(|v| *v)
                 {

compiler/rustc_const_eval/src/interpret/projection.rs

@@ -99,7 +99,7 @@ pub trait Projectable<'tcx, Prov: Provenance>: Sized + std::fmt::Debug {
 /// A type representing iteration over the elements of an array.
 pub struct ArrayIterator<'tcx, 'a, Prov: Provenance, P: Projectable<'tcx, Prov>> {
     base: &'a P,
-    range: Range<u64>,
+    range: <Range<u64> as IntoIterator>::IntoIter,
     stride: Size,
     field_layout: TyAndLayout<'tcx>,
     _phantom: PhantomData<Prov>, // otherwise it says `Prov` is never used...
@@ -280,7 +280,13 @@ where
         debug!("project_array_fields: {base:?} {len}");
         base.offset(len * stride, self.layout_of(self.tcx.types.unit).unwrap(), self)?;
         // Create the iterator.
-        Ok(ArrayIterator { base, range: 0..len, stride, field_layout, _phantom: PhantomData })
+        Ok(ArrayIterator {
+            base,
+            range: (0..len).into_iter(),
+            stride,
+            field_layout,
+            _phantom: PhantomData,
+        })
     }
 
     /// Subslicing

compiler/rustc_error_codes/src/error_codes/E0562.md

@@ -5,7 +5,7 @@ Erroneous code example:
 
 ```compile_fail,E0562
 fn main() {
-    let count_to_ten: impl Iterator<Item=usize> = 0..10;
+    let count_to_ten: impl IntoIterator<Item=usize> = 0..10;
     // error: `impl Trait` not allowed outside of function and inherent method
     //        return types
     for i in count_to_ten {
@@ -17,7 +17,7 @@ fn main() {
 Make sure `impl Trait` only appears in return-type position.
 
 ```
-fn count_to_n(n: usize) -> impl Iterator<Item=usize> {
+fn count_to_n(n: usize) -> impl IntoIterator<Item=usize> {
     0..n
 }
 

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -251,7 +251,7 @@ impl<T: ParameterizedOverTcx> LazyValue<T> {
 }
 
 struct DecodeIterator<'a, 'tcx, T> {
-    elem_counter: std::ops::Range<usize>,
+    elem_counter: <std::ops::Range<usize> as IntoIterator>::IntoIter,
     dcx: DecodeContext<'a, 'tcx>,
     _phantom: PhantomData<fn() -> T>,
 }
@@ -294,7 +294,7 @@ impl<T: ParameterizedOverTcx> LazyArray<T> {
     {
         let mut dcx = metadata.decoder(self.position.get());
         dcx.lazy_state = LazyState::NodeStart(self.position);
-        DecodeIterator { elem_counter: (0..self.num_elems), dcx, _phantom: PhantomData }
+        DecodeIterator { elem_counter: (0..self.num_elems).into_iter(), dcx, _phantom: PhantomData }
     }
 }
 

compiler/rustc_middle/src/mir/interpret/allocation/init_mask.rs

@@ -534,7 +534,7 @@ impl InitMaskMaterialized {
             end: Size,
             is_init: bool,
         ) -> Option<Size> {
-            (start..end).find(|&i| init_mask.get(i) == is_init)
+            (start..end).into_iter().find(|&i| init_mask.get(i) == is_init)
         }
 
         let result = find_bit_fast(self, start, end, is_init);

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -2905,7 +2905,7 @@ impl<'a> Parser<'a> {
     }
 
     pub fn is_diff_marker(&mut self, long_kind: &TokenKind, short_kind: &TokenKind) -> bool {
-        (0..3).all(|i| self.look_ahead(i, |tok| tok == long_kind))
+        (0..3).into_iter().all(|i| self.look_ahead(i, |tok| tok == long_kind))
             && self.look_ahead(3, |tok| tok == short_kind)
     }
 

compiler/rustc_parse/src/parser/mod.rs

@@ -1082,7 +1082,7 @@ impl<'a> Parser<'a> {
             // we are in has non-skipped delimiters. Look for skipped
             // delimiters in the lookahead range.
             let tree_cursor = &self.token_cursor.tree_cursor;
-            let all_normal = (0..dist).all(|i| {
+            let all_normal = (0..dist).into_iter().all(|i| {
                 let token = tree_cursor.look_ahead(i);
                 !matches!(token, Some(TokenTree::Delimited(.., Delimiter::Invisible, _)))
             });

library/alloc/src/collections/btree/node.rs

@@ -546,7 +546,7 @@ impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
 impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Internal> {
     /// # Safety
     /// Every item returned by `range` is a valid edge index for the node.
-    unsafe fn correct_childrens_parent_links<R: Iterator<Item = usize>>(&mut self, range: R) {
+    unsafe fn correct_childrens_parent_links<R: IntoIterator<Item = usize>>(&mut self, range: R) {
         for i in range {
             debug_assert!(i <= self.len());
             unsafe { Handle::new_edge(self.reborrow_mut(), i) }.correct_parent_link();

library/alloc/src/collections/vec_deque/tests.rs

@@ -899,10 +899,13 @@ fn test_extend_impl(trusted_len: bool) {
             Self { test: VecDeque::new(), expected: VecDeque::new(), trusted_len }
         }
 
-        fn test_extend<I>(&mut self, iter: I)
+        fn test_extend<I, IntoIter>(&mut self, iter: I)
         where
-            I: Iterator<Item = usize> + TrustedLen + Clone,
+            I: IntoIterator<IntoIter = IntoIter>,
+            IntoIter: Iterator<Item = usize> + TrustedLen + Clone,
         {
+            let iter = iter.into_iter();
+
             struct BasicIterator<I>(I);
             impl<I> Iterator for BasicIterator<I>
             where

library/alloc/src/vec/mod.rs

@@ -1943,7 +1943,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// #![feature(vec_push_within_capacity)]
     ///
     /// use std::collections::TryReserveError;
-    /// fn from_iter_fallible<T>(iter: impl Iterator<Item=T>) -> Result<Vec<T>, TryReserveError> {
+    /// fn from_iter_fallible<T>(iter: impl IntoIterator<Item=T>) -> Result<Vec<T>, TryReserveError> {
     ///     let mut vec = Vec::new();
     ///     for value in iter {
     ///         if let Err(value) = vec.push_within_capacity(value) {

library/alloc/tests/str.rs

@@ -590,15 +590,15 @@ mod slice_index {
 
             good: data[0..=5] == "abcdef";
             good: data[{
-                let mut iter = 0..=5;
+                let mut iter = core::ops::range::legacy::RangeInclusive::from(0..=5);
                 iter.by_ref().count(); // exhaust it
                 iter
             }] == "";
 
             // 0..=6 is out of bounds before exhaustion, so it
             // stands to reason that it still would be after.
             bad: data[{
-                let mut iter = 0..=6;
+                let mut iter = core::ops::range::legacy::RangeInclusive::from(0..=6);
                 iter.by_ref().count(); // exhaust it
                 iter
             }];

library/core/benches/iter.rs

@@ -493,42 +493,42 @@ fn bench_next_chunk_trusted_random_access(b: &mut Bencher) {
 
 #[bench]
 fn bench_next_chunk_filter_even(b: &mut Bencher) {
-    let a = (0..1024).next_chunk::<1024>().unwrap();
+    let a = (0..1024).into_iter().next_chunk::<1024>().unwrap();
 
     b.iter(|| black_box(&a).iter().filter(|&&i| i % 2 == 0).next_chunk::<32>())
 }
 
 #[bench]
 fn bench_next_chunk_filter_predictably_true(b: &mut Bencher) {
-    let a = (0..1024).next_chunk::<1024>().unwrap();
+    let a = (0..1024).into_iter().next_chunk::<1024>().unwrap();
 
     b.iter(|| black_box(&a).iter().filter(|&&i| i < 100).next_chunk::<32>())
 }
 
 #[bench]
 fn bench_next_chunk_filter_mostly_false(b: &mut Bencher) {
-    let a = (0..1024).next_chunk::<1024>().unwrap();
+    let a = (0..1024).into_iter().next_chunk::<1024>().unwrap();
 
     b.iter(|| black_box(&a).iter().filter(|&&i| i > 900).next_chunk::<32>())
 }
 
 #[bench]
 fn bench_next_chunk_filter_map_even(b: &mut Bencher) {
-    let a = (0..1024).next_chunk::<1024>().unwrap();
+    let a = (0..1024).into_iter().next_chunk::<1024>().unwrap();
 
     b.iter(|| black_box(&a).iter().filter_map(|&i| (i % 2 == 0).then(|| i)).next_chunk::<32>())
 }
 
 #[bench]
 fn bench_next_chunk_filter_map_predictably_true(b: &mut Bencher) {
-    let a = (0..1024).next_chunk::<1024>().unwrap();
+    let a = (0..1024).into_iter().next_chunk::<1024>().unwrap();
 
     b.iter(|| black_box(&a).iter().filter_map(|&i| (i < 100).then(|| i)).next_chunk::<32>())
 }
 
 #[bench]
 fn bench_next_chunk_filter_map_mostly_false(b: &mut Bencher) {
-    let a = (0..1024).next_chunk::<1024>().unwrap();
+    let a = (0..1024).into_iter().next_chunk::<1024>().unwrap();
 
     b.iter(|| black_box(&a).iter().filter_map(|&i| (i > 900).then(|| i)).next_chunk::<32>())
 }

library/core/src/array/iter.rs

@@ -132,9 +132,9 @@ impl<T, const N: usize> IntoIter<T, N> {
     ///     unsafe { Ok(buffer.transpose().assume_init()) }
     /// }
     ///
-    /// let r: [_; 4] = next_chunk(&mut (10..16)).unwrap();
+    /// let r: [_; 4] = next_chunk(&mut (10..16).into_iter()).unwrap();
     /// assert_eq!(r, [10, 11, 12, 13]);
-    /// let r: IntoIter<_, 40> = next_chunk(&mut (10..16)).unwrap_err();
+    /// let r: IntoIter<_, 40> = next_chunk(&mut (10..16).into_iter()).unwrap_err();
     /// assert_eq!(r.collect::<Vec<_>>(), vec![10, 11, 12, 13, 14, 15]);
     /// ```
     #[unstable(feature = "array_into_iter_constructors", issue = "91583")]

library/core/src/escape.rs

@@ -1,6 +1,7 @@
 //! Helper code for character escaping.
 
 use crate::ascii;
+use crate::iter::range::RangeIter;
 use crate::num::NonZeroUsize;
 use crate::ops::Range;
 
@@ -68,14 +69,14 @@ pub(crate) struct EscapeIterInner<const N: usize> {
     pub(crate) data: [ascii::Char; N],
 
     // Invariant: alive.start <= alive.end <= N.
-    pub(crate) alive: Range<u8>,
+    pub(crate) alive: RangeIter<u8>,
 }
 
 impl<const N: usize> EscapeIterInner<N> {
     pub fn new(data: [ascii::Char; N], alive: Range<u8>) -> Self {
         const { assert!(N < 256) };
         debug_assert!(alive.start <= alive.end && usize::from(alive.end) <= N, "{alive:?}");
-        Self { data, alive }
+        Self { data, alive: alive.into_iter() }
     }
 
     pub fn from_array<const M: usize>(array: [ascii::Char; M]) -> Self {
@@ -87,15 +88,15 @@ impl<const N: usize> EscapeIterInner<N> {
     }
 
     pub fn as_ascii(&self) -> &[ascii::Char] {
-        &self.data[usize::from(self.alive.start)..usize::from(self.alive.end)]
+        &self.data[usize::from(self.alive.inner.start)..usize::from(self.alive.inner.end)]
     }
 
     pub fn as_str(&self) -> &str {
         self.as_ascii().as_str()
     }
 
     pub fn len(&self) -> usize {
-        usize::from(self.alive.end - self.alive.start)
+        usize::from(self.alive.inner.end - self.alive.inner.start)
     }
 
     pub fn next(&mut self) -> Option<u8> {