diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs index 4a2cf15277441..e78a442e97600 100644 --- a/library/core/src/array/mod.rs +++ b/library/core/src/array/mod.rs @@ -1003,9 +1003,10 @@ impl const Drop for Guard<'_, T> { /// dropped. /// /// Used for [`Iterator::next_chunk`]. +#[rustc_const_unstable(feature = "const_iter", issue = "92476")] #[inline] -pub(crate) fn iter_next_chunk( - iter: &mut impl Iterator, +pub(crate) const fn iter_next_chunk( + iter: &mut impl [const] Iterator, ) -> Result<[T; N], IntoIter> { let mut array = [const { MaybeUninit::uninit() }; N]; let r = iter_next_chunk_erased(&mut array, iter); @@ -1026,10 +1027,11 @@ pub(crate) fn iter_next_chunk( /// /// Unfortunately this loop has two exit conditions, the buffer filling up /// or the iterator running out of items, making it tend to optimize poorly. +#[rustc_const_unstable(feature = "const_iter", issue = "92476")] #[inline] -fn iter_next_chunk_erased( +const fn iter_next_chunk_erased( buffer: &mut [MaybeUninit], - iter: &mut impl Iterator, + iter: &mut impl [const] Iterator, ) -> Result<(), usize> { // if `Iterator::next` panics, this guard will drop already initialized items let mut guard = Guard { array_mut: buffer, initialized: 0 }; diff --git a/library/core/src/iter/adapters/array_chunks.rs b/library/core/src/iter/adapters/array_chunks.rs index 7c003cff10c7b..a3e5ae5e7698b 100644 --- a/library/core/src/iter/adapters/array_chunks.rs +++ b/library/core/src/iter/adapters/array_chunks.rs @@ -26,7 +26,7 @@ where I: Iterator, { #[track_caller] - pub(in crate::iter) fn new(iter: I) -> Self { + pub(in crate::iter) const fn new(iter: I) -> Self { assert!(N != 0, "chunk size must be non-zero"); Self { iter, remainder: None } } diff --git a/library/core/src/iter/adapters/chain.rs b/library/core/src/iter/adapters/chain.rs index 0ece54554d464..d143b67fd4353 100644 --- a/library/core/src/iter/adapters/chain.rs +++ b/library/core/src/iter/adapters/chain.rs @@ -33,7 +33,7 @@ pub struct Chain { b: Option, } impl Chain { - pub(in super::super) fn new(a: A, b: B) -> Chain { + pub(in super::super) const fn new(a: A, b: B) -> Chain { Chain { a: Some(a), b: Some(b) } } } diff --git a/library/core/src/iter/adapters/cloned.rs b/library/core/src/iter/adapters/cloned.rs index aea6d64281aec..54d132813e4db 100644 --- a/library/core/src/iter/adapters/cloned.rs +++ b/library/core/src/iter/adapters/cloned.rs @@ -20,7 +20,7 @@ pub struct Cloned { } impl Cloned { - pub(in crate::iter) fn new(it: I) -> Cloned { + pub(in crate::iter) const fn new(it: I) -> Cloned { Cloned { it } } } diff --git a/library/core/src/iter/adapters/copied.rs b/library/core/src/iter/adapters/copied.rs index 9627ace29795c..ba87fb7216059 100644 --- a/library/core/src/iter/adapters/copied.rs +++ b/library/core/src/iter/adapters/copied.rs @@ -21,7 +21,7 @@ pub struct Copied { } impl Copied { - pub(in crate::iter) fn new(it: I) -> Copied { + pub(in crate::iter) const fn new(it: I) -> Copied { Copied { it } } diff --git a/library/core/src/iter/adapters/cycle.rs b/library/core/src/iter/adapters/cycle.rs index 6cb1a3a46763e..8fb54efbd3209 100644 --- a/library/core/src/iter/adapters/cycle.rs +++ b/library/core/src/iter/adapters/cycle.rs @@ -18,7 +18,11 @@ pub struct Cycle { } impl Cycle { - pub(in crate::iter) fn new(iter: I) -> Cycle { + #[rustc_const_unstable(feature = "const_iter", issue = "92476")] + pub(in crate::iter) const fn new(iter: I) -> Cycle + where + I: [const] Clone, + { Cycle { orig: iter.clone(), iter } } } diff --git a/library/core/src/iter/adapters/enumerate.rs b/library/core/src/iter/adapters/enumerate.rs index f7b9f0b7a5e9d..916ba88e6160a 100644 --- a/library/core/src/iter/adapters/enumerate.rs +++ b/library/core/src/iter/adapters/enumerate.rs @@ -20,7 +20,7 @@ pub struct Enumerate { count: usize, } impl Enumerate { - pub(in crate::iter) fn new(iter: I) -> Enumerate { + pub(in crate::iter) const fn new(iter: I) -> Enumerate { Enumerate { iter, count: 0 } } diff --git a/library/core/src/iter/adapters/filter.rs b/library/core/src/iter/adapters/filter.rs index b22419ccf080a..cf21536784a28 100644 --- a/library/core/src/iter/adapters/filter.rs +++ b/library/core/src/iter/adapters/filter.rs @@ -24,7 +24,7 @@ pub struct Filter { predicate: P, } impl Filter { - pub(in crate::iter) fn new(iter: I, predicate: P) -> Filter { + pub(in crate::iter) const fn new(iter: I, predicate: P) -> Filter { Filter { iter, predicate } } } diff --git a/library/core/src/iter/adapters/filter_map.rs b/library/core/src/iter/adapters/filter_map.rs index 24ec6b1741ce1..3fd7e16d1c148 100644 --- a/library/core/src/iter/adapters/filter_map.rs +++ b/library/core/src/iter/adapters/filter_map.rs @@ -20,7 +20,7 @@ pub struct FilterMap { f: F, } impl FilterMap { - pub(in crate::iter) fn new(iter: I, f: F) -> FilterMap { + pub(in crate::iter) const fn new(iter: I, f: F) -> FilterMap { FilterMap { iter, f } } } diff --git a/library/core/src/iter/adapters/flatten.rs b/library/core/src/iter/adapters/flatten.rs index c50f07ff6bb66..02a416e6cc869 100644 --- a/library/core/src/iter/adapters/flatten.rs +++ b/library/core/src/iter/adapters/flatten.rs @@ -186,7 +186,11 @@ pub struct Flatten> { } impl> Flatten { - pub(in super::super) fn new(iter: I) -> Flatten { + #[rustc_const_unstable(feature = "const_iter", issue = "92476")] + pub(in super::super) const fn new(iter: I) -> Flatten + where + I: [const] Iterator, + { Flatten { inner: FlattenCompat::new(iter) } } } @@ -363,7 +367,11 @@ where I: Iterator, { /// Adapts an iterator by flattening it, for use in `flatten()` and `flat_map()`. - fn new(iter: I) -> FlattenCompat { + #[rustc_const_unstable(feature = "const_iter", issue = "92476")] + const fn new(iter: I) -> FlattenCompat + where + I: [const] Iterator, + { FlattenCompat { iter: iter.fuse(), frontiter: None, backiter: None } } } diff --git a/library/core/src/iter/adapters/fuse.rs b/library/core/src/iter/adapters/fuse.rs index 0072a95e8dfe0..ef956e8bdef5d 100644 --- a/library/core/src/iter/adapters/fuse.rs +++ b/library/core/src/iter/adapters/fuse.rs @@ -21,7 +21,7 @@ pub struct Fuse { iter: Option, } impl Fuse { - pub(in crate::iter) fn new(iter: I) -> Fuse { + pub(in crate::iter) const fn new(iter: I) -> Fuse { Fuse { iter: Some(iter) } } diff --git a/library/core/src/iter/adapters/inspect.rs b/library/core/src/iter/adapters/inspect.rs index 0e2a68a503e44..de94951bc80ff 100644 --- a/library/core/src/iter/adapters/inspect.rs +++ b/library/core/src/iter/adapters/inspect.rs @@ -20,7 +20,7 @@ pub struct Inspect { f: F, } impl Inspect { - pub(in crate::iter) fn new(iter: I, f: F) -> Inspect { + pub(in crate::iter) const fn new(iter: I, f: F) -> Inspect { Inspect { iter, f } } } diff --git a/library/core/src/iter/adapters/map_while.rs b/library/core/src/iter/adapters/map_while.rs index c047c40de050e..3e34427da6142 100644 --- a/library/core/src/iter/adapters/map_while.rs +++ b/library/core/src/iter/adapters/map_while.rs @@ -20,7 +20,7 @@ pub struct MapWhile { } impl MapWhile { - pub(in crate::iter) fn new(iter: I, predicate: P) -> MapWhile { + pub(in crate::iter) const fn new(iter: I, predicate: P) -> MapWhile { MapWhile { iter, predicate } } } diff --git a/library/core/src/iter/adapters/map_windows.rs b/library/core/src/iter/adapters/map_windows.rs index cef556319143e..a976e5e7bce49 100644 --- a/library/core/src/iter/adapters/map_windows.rs +++ b/library/core/src/iter/adapters/map_windows.rs @@ -46,7 +46,7 @@ struct Buffer { } impl MapWindows { - pub(in crate::iter) fn new(iter: I, f: F) -> Self { + pub(in crate::iter) const fn new(iter: I, f: F) -> Self { assert!(N != 0, "array in `Iterator::map_windows` must contain more than 0 elements"); // Only ZST arrays' length can be so large. @@ -63,7 +63,7 @@ impl MapWindows { impl MapWindowsInner { #[inline] - fn new(iter: I) -> Self { + const fn new(iter: I) -> Self { Self { iter: Some(iter), buffer: None } } diff --git a/library/core/src/iter/adapters/peekable.rs b/library/core/src/iter/adapters/peekable.rs index 9f6d1df57dbe8..4bddc2025c26e 100644 --- a/library/core/src/iter/adapters/peekable.rs +++ b/library/core/src/iter/adapters/peekable.rs @@ -21,7 +21,7 @@ pub struct Peekable { } impl Peekable { - pub(in crate::iter) fn new(iter: I) -> Peekable { + pub(in crate::iter) const fn new(iter: I) -> Peekable { Peekable { iter, peeked: None } } } diff --git a/library/core/src/iter/adapters/rev.rs b/library/core/src/iter/adapters/rev.rs index 17d3eef597dcb..b9ada504525f9 100644 --- a/library/core/src/iter/adapters/rev.rs +++ b/library/core/src/iter/adapters/rev.rs @@ -17,7 +17,7 @@ pub struct Rev { } impl Rev { - pub(in crate::iter) fn new(iter: T) -> Rev { + pub(in crate::iter) const fn new(iter: T) -> Rev { Rev { iter } } diff --git a/library/core/src/iter/adapters/scan.rs b/library/core/src/iter/adapters/scan.rs index e12375c94e067..7d084a89bd940 100644 --- a/library/core/src/iter/adapters/scan.rs +++ b/library/core/src/iter/adapters/scan.rs @@ -21,7 +21,7 @@ pub struct Scan { } impl Scan { - pub(in crate::iter) fn new(iter: I, state: St, f: F) -> Scan { + pub(in crate::iter) const fn new(iter: I, state: St, f: F) -> Scan { Scan { iter, state, f } } } diff --git a/library/core/src/iter/adapters/skip.rs b/library/core/src/iter/adapters/skip.rs index 55c4a7f14fbd6..f7a6beb2b8c63 100644 --- a/library/core/src/iter/adapters/skip.rs +++ b/library/core/src/iter/adapters/skip.rs @@ -24,7 +24,7 @@ pub struct Skip { } impl Skip { - pub(in crate::iter) fn new(iter: I, n: usize) -> Skip { + pub(in crate::iter) const fn new(iter: I, n: usize) -> Skip { Skip { iter, n } } } diff --git a/library/core/src/iter/adapters/skip_while.rs b/library/core/src/iter/adapters/skip_while.rs index 8ae453e76fa0d..ced4fd8f2abc4 100644 --- a/library/core/src/iter/adapters/skip_while.rs +++ b/library/core/src/iter/adapters/skip_while.rs @@ -21,7 +21,7 @@ pub struct SkipWhile { } impl SkipWhile { - pub(in crate::iter) fn new(iter: I, predicate: P) -> SkipWhile { + pub(in crate::iter) const fn new(iter: I, predicate: P) -> SkipWhile { SkipWhile { iter, flag: false, predicate } } } diff --git a/library/core/src/iter/adapters/take.rs b/library/core/src/iter/adapters/take.rs index b96335f415257..ecd462c60eda3 100644 --- a/library/core/src/iter/adapters/take.rs +++ b/library/core/src/iter/adapters/take.rs @@ -20,7 +20,7 @@ pub struct Take { } impl Take { - pub(in crate::iter) fn new(iter: I, n: usize) -> Take { + pub(in crate::iter) const fn new(iter: I, n: usize) -> Take { Take { iter, n } } } diff --git a/library/core/src/iter/adapters/take_while.rs b/library/core/src/iter/adapters/take_while.rs index 06028ea98e7fd..6e40629567a83 100644 --- a/library/core/src/iter/adapters/take_while.rs +++ b/library/core/src/iter/adapters/take_while.rs @@ -21,7 +21,7 @@ pub struct TakeWhile { } impl TakeWhile { - pub(in crate::iter) fn new(iter: I, predicate: P) -> TakeWhile { + pub(in crate::iter) const fn new(iter: I, predicate: P) -> TakeWhile { TakeWhile { iter, flag: false, predicate } } } diff --git a/library/core/src/iter/traits/accum.rs b/library/core/src/iter/traits/accum.rs index 375b5ef52859f..3787e41f0a0b1 100644 --- a/library/core/src/iter/traits/accum.rs +++ b/library/core/src/iter/traits/accum.rs @@ -10,11 +10,12 @@ use crate::num::{Saturating, Wrapping}; /// [`sum()`]: Iterator::sum /// [`FromIterator`]: iter::FromIterator #[stable(feature = "iter_arith_traits", since = "1.12.0")] +#[rustc_const_unstable(feature = "const_iter", issue = "92476")] #[diagnostic::on_unimplemented( message = "a value of type `{Self}` cannot be made by summing an iterator over elements of type `{A}`", label = "value of type `{Self}` cannot be made by summing a `std::iter::Iterator`" )] -pub trait Sum: Sized { +pub const trait Sum: Sized { /// Takes an iterator and generates `Self` from the elements by "summing up" /// the items. #[stable(feature = "iter_arith_traits", since = "1.12.0")] @@ -31,11 +32,12 @@ pub trait Sum: Sized { /// [`product()`]: Iterator::product /// [`FromIterator`]: iter::FromIterator #[stable(feature = "iter_arith_traits", since = "1.12.0")] +#[rustc_const_unstable(feature = "const_iter", issue = "92476")] #[diagnostic::on_unimplemented( message = "a value of type `{Self}` cannot be made by multiplying all elements of type `{A}` from an iterator", label = "value of type `{Self}` cannot be made by multiplying all elements from a `std::iter::Iterator`" )] -pub trait Product: Sized { +pub const trait Product: Sized { /// Takes an iterator and generates `Self` from the elements by multiplying /// the items. #[stable(feature = "iter_arith_traits", since = "1.12.0")] diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs index 2e82f45771823..dc2dd1d35bea0 100644 --- a/library/core/src/iter/traits/iterator.rs +++ b/library/core/src/iter/traits/iterator.rs @@ -7,6 +7,7 @@ use super::super::{ use super::TrustedLen; use crate::array; use crate::cmp::{self, Ordering}; +use crate::marker::Destruct; use crate::num::NonZero; use crate::ops::{ChangeOutputType, ControlFlow, FromResidual, Residual, Try}; @@ -108,7 +109,6 @@ pub const trait Iterator { /// ``` #[inline] #[unstable(feature = "iter_next_chunk", issue = "98326")] - #[rustc_non_const_trait_method] fn next_chunk( &mut self, ) -> Result<[Self::Item; N], array::IntoIter> @@ -221,16 +221,18 @@ pub const trait Iterator { /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn count(self) -> usize where - Self: Sized, + Self: Sized + [const] Destruct, + Self::Item: [const] Destruct, { - self.fold( - 0, - #[rustc_inherit_overflow_checks] - |count, _| count + 1, - ) + // FIXME(const-hack): this should be a const closure + #[rustc_const_unstable(feature = "const_iter", issue = "92476")] + #[rustc_inherit_overflow_checks] + const fn plus_one(accum: usize, _elem: T) -> usize { + accum + 1 + } + self.fold(0, plus_one) } /// Consumes the iterator, returning the last element. @@ -254,13 +256,14 @@ pub const trait Iterator { /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn last(self) -> Option where - Self: Sized, + Self: Sized + [const] Destruct, + Self::Item: [const] Destruct, { + #[rustc_const_unstable(feature = "const_iter", issue = "92476")] #[inline] - fn some(_: Option, x: T) -> Option { + const fn some(_: Option, x: T) -> Option { Some(x) } @@ -302,32 +305,54 @@ pub const trait Iterator { /// ``` #[inline] #[unstable(feature = "iter_advance_by", issue = "77404")] - #[rustc_non_const_trait_method] - fn advance_by(&mut self, n: usize) -> Result<(), NonZero> { + fn advance_by(&mut self, n: usize) -> Result<(), NonZero> + where + Self::Item: [const] Destruct, + { /// Helper trait to specialize `advance_by` via `try_fold` for `Sized` iterators. - trait SpecAdvanceBy { + const trait SpecAdvanceBy { fn spec_advance_by(&mut self, n: usize) -> Result<(), NonZero>; } - impl SpecAdvanceBy for I { + #[rustc_const_unstable(feature = "const_iter", issue = "92476")] + impl const SpecAdvanceBy for I + where + I::Item: [const] Destruct, + { default fn spec_advance_by(&mut self, n: usize) -> Result<(), NonZero> { - for i in 0..n { + // FIXME(const-hack): this should be `for i in 0..n` + let mut i: usize = 0; + while i < n { if self.next().is_none() { // SAFETY: `i` is always less than `n`. return Err(unsafe { NonZero::new_unchecked(n - i) }); } + i += 1; } Ok(()) } } - impl SpecAdvanceBy for I { + #[rustc_const_unstable(feature = "const_iter", issue = "92476")] + impl const SpecAdvanceBy for I + where + I::Item: [const] Destruct, + { fn spec_advance_by(&mut self, n: usize) -> Result<(), NonZero> { + // FIXME(const-hack): this should be a const closure + #[rustc_const_unstable(feature = "const_iter", issue = "92476")] + const fn minus_one( + accum: NonZero, + _elem: T, + ) -> Option> { + NonZero::new(accum.get() - 1) + } + let Some(n) = NonZero::new(n) else { return Ok(()); }; - let res = self.try_fold(n, |n, _| NonZero::new(n.get() - 1)); + let res = self.try_fold(n, minus_one); match res { None => Ok(()), @@ -380,8 +405,10 @@ pub const trait Iterator { /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] - fn nth(&mut self, n: usize) -> Option { + fn nth(&mut self, n: usize) -> Option + where + Self::Item: [const] Destruct, + { self.advance_by(n).ok()?; self.next() } @@ -503,11 +530,10 @@ pub const trait Iterator { /// [`OsStr`]: ../../std/ffi/struct.OsStr.html #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn chain(self, other: U) -> Chain where Self: Sized, - U: IntoIterator, + U: [const] IntoIterator, { Chain::new(self, other.into_iter()) } @@ -923,7 +949,6 @@ pub const trait Iterator { #[inline] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_diagnostic_item = "iter_filter"] - #[rustc_non_const_trait_method] fn filter

(self, predicate: P) -> Filter where Self: Sized, @@ -969,7 +994,6 @@ pub const trait Iterator { /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn filter_map(self, f: F) -> FilterMap where Self: Sized, @@ -1017,7 +1041,6 @@ pub const trait Iterator { #[inline] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_diagnostic_item = "enumerate_method"] - #[rustc_non_const_trait_method] fn enumerate(self) -> Enumerate where Self: Sized, @@ -1089,7 +1112,6 @@ pub const trait Iterator { /// [`next`]: Iterator::next #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn peekable(self) -> Peekable where Self: Sized, @@ -1155,7 +1177,6 @@ pub const trait Iterator { #[inline] #[doc(alias = "drop_while")] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn skip_while

(self, predicate: P) -> SkipWhile where Self: Sized, @@ -1234,7 +1255,6 @@ pub const trait Iterator { /// the iteration should stop, but wasn't placed back into the iterator. #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn take_while

(self, predicate: P) -> TakeWhile where Self: Sized, @@ -1323,7 +1343,6 @@ pub const trait Iterator { /// [`fuse`]: Iterator::fuse #[inline] #[stable(feature = "iter_map_while", since = "1.57.0")] - #[rustc_non_const_trait_method] fn map_while(self, predicate: P) -> MapWhile where Self: Sized, @@ -1353,7 +1372,6 @@ pub const trait Iterator { /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn skip(self, n: usize) -> Skip where Self: Sized, @@ -1426,7 +1444,6 @@ pub const trait Iterator { #[doc(alias = "limit")] #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn take(self, n: usize) -> Take where Self: Sized, @@ -1474,7 +1491,6 @@ pub const trait Iterator { /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn scan(self, initial_state: St, f: F) -> Scan where Self: Sized, @@ -1598,7 +1614,6 @@ pub const trait Iterator { /// [`flat_map()`]: Iterator::flat_map #[inline] #[stable(feature = "iterator_flatten", since = "1.29.0")] - #[rustc_non_const_trait_method] fn flatten(self) -> Flatten where Self: Sized, @@ -1755,7 +1770,6 @@ pub const trait Iterator { /// ``` #[inline] #[unstable(feature = "iter_map_windows", issue = "87155")] - #[rustc_non_const_trait_method] fn map_windows(self, f: F) -> MapWindows where Self: Sized, @@ -1818,7 +1832,6 @@ pub const trait Iterator { /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn fuse(self) -> Fuse where Self: Sized, @@ -1903,7 +1916,6 @@ pub const trait Iterator { /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn inspect(self, f: F) -> Inspect where Self: Sized, @@ -2473,12 +2485,11 @@ pub const trait Iterator { /// ``` #[inline] #[stable(feature = "iterator_try_fold", since = "1.27.0")] - #[rustc_non_const_trait_method] fn try_fold(&mut self, init: B, mut f: F) -> R where Self: Sized, - F: FnMut(B, Self::Item) -> R, - R: Try, + F: [const] FnMut(B, Self::Item) -> R + [const] Destruct, + R: [const] Try, { let mut accum = init; while let Some(x) = self.next() { @@ -2540,7 +2551,10 @@ pub const trait Iterator { R: Try, { #[inline] - fn call(mut f: impl FnMut(T) -> R) -> impl FnMut((), T) -> R { + fn call(mut f: impl FnMut(T) -> R) -> impl FnMut((), T) -> R + where + R: Try, + { move |(), x| f(x) } @@ -2652,11 +2666,10 @@ pub const trait Iterator { #[doc(alias = "inject", alias = "foldl")] #[inline] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn fold(mut self, init: B, mut f: F) -> B where - Self: Sized, - F: FnMut(B, Self::Item) -> B, + Self: Sized + [const] Destruct, + F: [const] FnMut(B, Self::Item) -> B + [const] Destruct, { let mut accum = init; while let Some(x) = self.next() { @@ -2690,11 +2703,10 @@ pub const trait Iterator { /// ``` #[inline] #[stable(feature = "iterator_fold_self", since = "1.51.0")] - #[rustc_non_const_trait_method] fn reduce(mut self, f: F) -> Option where - Self: Sized, - F: FnMut(Self::Item, Self::Item) -> Self::Item, + Self: Sized + [const] Destruct, + F: [const] FnMut(Self::Item, Self::Item) -> Self::Item + [const] Destruct, { let first = self.next()?; Some(self.fold(first, f)) @@ -2762,14 +2774,13 @@ pub const trait Iterator { /// ``` #[inline] #[unstable(feature = "iterator_try_reduce", issue = "87053")] - #[rustc_non_const_trait_method] fn try_reduce( &mut self, - f: impl FnMut(Self::Item, Self::Item) -> R, + f: impl [const] FnMut(Self::Item, Self::Item) -> R + [const] Destruct, ) -> ChangeOutputType> where Self: Sized, - R: Try>>, + R: [const] Try>>, { let first = match self.next() { Some(i) => i, @@ -3434,7 +3445,6 @@ pub const trait Iterator { #[inline] #[doc(alias = "reverse")] #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_non_const_trait_method] fn rev(self) -> Rev where Self: Sized + DoubleEndedIterator, @@ -3503,7 +3513,6 @@ pub const trait Iterator { /// ``` #[stable(feature = "iter_copied", since = "1.36.0")] #[rustc_diagnostic_item = "iter_copied"] - #[rustc_non_const_trait_method] fn copied<'a, T>(self) -> Copied where T: Copy + 'a, @@ -3552,7 +3561,6 @@ pub const trait Iterator { /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[rustc_diagnostic_item = "iter_cloned"] - #[rustc_non_const_trait_method] fn cloned<'a, T>(self) -> Cloned where T: Clone + 'a, @@ -3584,10 +3592,9 @@ pub const trait Iterator { /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[inline] - #[rustc_non_const_trait_method] fn cycle(self) -> Cycle where - Self: Sized + Clone, + Self: Sized + [const] Clone, { Cycle::new(self) } @@ -3628,7 +3635,6 @@ pub const trait Iterator { /// ``` #[track_caller] #[unstable(feature = "iter_array_chunks", issue = "100450")] - #[rustc_non_const_trait_method] fn array_chunks(self) -> ArrayChunks where Self: Sized, @@ -3665,11 +3671,10 @@ pub const trait Iterator { /// assert_eq!(sum, -0.0_f32); /// ``` #[stable(feature = "iter_arith", since = "1.11.0")] - #[rustc_non_const_trait_method] fn sum(self) -> S where Self: Sized, - S: Sum, + S: [const] Sum, { Sum::sum(self) } @@ -3698,11 +3703,10 @@ pub const trait Iterator { /// assert_eq!(factorial(5), 120); /// ``` #[stable(feature = "iter_arith", since = "1.11.0")] - #[rustc_non_const_trait_method] fn product

(self) -> P where Self: Sized, - P: Product, + P: [const] Product, { Product::product(self) } @@ -4199,7 +4203,7 @@ where F: FnMut(A::Item, B::Item) -> ControlFlow, { #[inline] - fn compare<'a, B, X, T>( + const fn compare<'a, B, X, T>( b: &'a mut B, mut f: impl FnMut(X, B::Item) -> ControlFlow + 'a, ) -> impl FnMut(X) -> ControlFlow> + 'a @@ -4211,7 +4215,6 @@ where Some(y) => f(x, y).map_break(ControlFlow::Break), } } - match a.try_for_each(compare(&mut b, f)) { ControlFlow::Continue(()) => ControlFlow::Continue(match b.next() { None => Ordering::Equal, diff --git a/tests/codegen-units/item-collection/opaque-return-impls.rs b/tests/codegen-units/item-collection/opaque-return-impls.rs index 484fbe7fe62f1..1425a51af73b0 100644 --- a/tests/codegen-units/item-collection/opaque-return-impls.rs +++ b/tests/codegen-units/item-collection/opaque-return-impls.rs @@ -73,15 +73,17 @@ pub fn foo3() -> Box> { } //~ MONO_ITEM fn ::spec_advance_by -//~ MONO_ITEM fn ::spec_advance_by::{closure#0} //~ MONO_ITEM fn ::advance_by +//~ MONO_ITEM fn ::try_fold::, fn(std::num::NonZero, usize) -> std::option::Option> {::spec_advance_by::minus_one::}, std::option::Option>> @@ opaque_return_impls-cgu.0[External] +//~ MONO_ITEM fn ::spec_advance_by::minus_one:: @@ opaque_return_impls-cgu.0[External] +//~ MONO_ITEM fn , usize) -> std::option::Option> {::spec_advance_by::minus_one::} as std::ops::FnMut<(std::num::NonZero, usize)>>::call_mut - shim(fn(std::num::NonZero, usize) -> std::option::Option> {::spec_advance_by::minus_one::}) @@ opaque_return_impls-cgu.0[Internal] //~ MONO_ITEM fn ::next //~ MONO_ITEM fn ::nth //~ MONO_ITEM fn ::size_hint -//~ MONO_ITEM fn ::try_fold::, {closure@::spec_advance_by::{closure#0}}, std::option::Option>> //~ MONO_ITEM fn > as std::ops::FromResidual>>::from_residual //~ MONO_ITEM fn > as std::ops::Try>::branch //~ MONO_ITEM fn > as std::ops::Try>::from_output + //~ MONO_ITEM fn foo3 //~ MONO_ITEM fn std::boxed::Box::::new //~ MONO_ITEM fn Counter::new diff --git a/tests/ui/typeck/typeck_type_placeholder_item.rs b/tests/ui/typeck/typeck_type_placeholder_item.rs index 48547c019d628..80bc8da519fca 100644 --- a/tests/ui/typeck/typeck_type_placeholder_item.rs +++ b/tests/ui/typeck/typeck_type_placeholder_item.rs @@ -239,5 +239,4 @@ fn evens_squared(n: usize) -> _ { const _: _ = (1..10).filter(|x| x % 2 == 0).map(|x| x * x); //~^ ERROR the placeholder -//~| ERROR cannot call non-const -//~| ERROR cannot call non-const +//~| ERROR the trait bound `std::ops::Range<{integer}>: const Iterator` is not satisfied diff --git a/tests/ui/typeck/typeck_type_placeholder_item.stderr b/tests/ui/typeck/typeck_type_placeholder_item.stderr index 2772d55f953a8..129cf9b50c10d 100644 --- a/tests/ui/typeck/typeck_type_placeholder_item.stderr +++ b/tests/ui/typeck/typeck_type_placeholder_item.stderr @@ -587,17 +587,20 @@ LL - fn evens_squared(n: usize) -> _ { LL + fn evens_squared(n: usize) -> impl Iterator { | -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants - --> $DIR/typeck_type_placeholder_item.rs:240:10 +error[E0277]: the trait bound `std::ops::Range<{integer}>: const Iterator` is not satisfied + --> $DIR/typeck_type_placeholder_item.rs:240:15 | LL | const _: _ = (1..10).filter(|x| x % 2 == 0).map(|x| x * x); - | ^ not allowed in type signatures + | ^^^^^ ------ required by a bound introduced by this call | -note: however, the inferred type `Map, {closure@typeck_type_placeholder_item.rs:240:29}>, {closure@typeck_type_placeholder_item.rs:240:49}>` cannot be named - --> $DIR/typeck_type_placeholder_item.rs:240:14 +note: trait `Iterator` is implemented but not `const` + --> $SRC_DIR/core/src/iter/range.rs:LL:COL + +error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants + --> $DIR/typeck_type_placeholder_item.rs:240:10 | LL | const _: _ = (1..10).filter(|x| x % 2 == 0).map(|x| x * x); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | ^ not allowed in type signatures error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types --> $DIR/typeck_type_placeholder_item.rs:40:24 @@ -678,23 +681,7 @@ LL | fn map(_: fn() -> Option<&'static T>) -> Option { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ = note: calls in constants are limited to constant functions, tuple structs and tuple variants -error[E0015]: cannot call non-const method ` as Iterator>::filter::<{closure@$DIR/typeck_type_placeholder_item.rs:240:29: 240:32}>` in constants - --> $DIR/typeck_type_placeholder_item.rs:240:22 - | -LL | const _: _ = (1..10).filter(|x| x % 2 == 0).map(|x| x * x); - | ^^^^^^^^^^^^^^^^^^^^^^ - | - = note: calls in constants are limited to constant functions, tuple structs and tuple variants - -error[E0015]: cannot call non-const method `, {closure@$DIR/typeck_type_placeholder_item.rs:240:29: 240:32}> as Iterator>::map::` in constants - --> $DIR/typeck_type_placeholder_item.rs:240:45 - | -LL | const _: _ = (1..10).filter(|x| x % 2 == 0).map(|x| x * x); - | ^^^^^^^^^^^^^^ - | - = note: calls in constants are limited to constant functions, tuple structs and tuple variants - -error: aborting due to 83 previous errors +error: aborting due to 82 previous errors -Some errors have detailed explanations: E0015, E0046, E0121, E0282, E0403. +Some errors have detailed explanations: E0015, E0046, E0121, E0277, E0282, E0403. For more information about an error, try `rustc --explain E0015`.