Auto merge of #90235 - matthiaskrgr:rollup-7pqtevk, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #89558 (Add rustc lint, warning when iterating over hashmaps)
 - #90100 (Skip documentation for tier 2 targets on dist-x86_64-apple-darwin)
 - #90155 (Fix alignment of method headings for scannability)
 - #90162 (Mark `{array, slice}::{from_ref, from_mut}` as const fn)
 - #90221 (Fix ICE when forgetting to `Box` a parameter to a `Self::func` call)
 - #90234 (Temporarily turn overflow checks off for rustc-rayon-core)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

8 files changed, 45 insertions, 4 deletions

diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs
index 73340fda2cb..811850af367 100644
--- a/library/core/src/array/mod.rs
+++ b/library/core/src/array/mod.rs
@@ -85,14 +85,16 @@ where
 
 /// Converts a reference to `T` into a reference to an array of length 1 (without copying).
 #[stable(feature = "array_from_ref", since = "1.53.0")]
-pub fn from_ref<T>(s: &T) -> &[T; 1] {
+#[rustc_const_unstable(feature = "const_array_from_ref", issue = "90206")]
+pub const fn from_ref<T>(s: &T) -> &[T; 1] {
     // SAFETY: Converting `&T` to `&[T; 1]` is sound.
     unsafe { &*(s as *const T).cast::<[T; 1]>() }
 }
 
 /// Converts a mutable reference to `T` into a mutable reference to an array of length 1 (without copying).
 #[stable(feature = "array_from_ref", since = "1.53.0")]
-pub fn from_mut<T>(s: &mut T) -> &mut [T; 1] {
+#[rustc_const_unstable(feature = "const_array_from_ref", issue = "90206")]
+pub const fn from_mut<T>(s: &mut T) -> &mut [T; 1] {
     // SAFETY: Converting `&mut T` to `&mut [T; 1]` is sound.
     unsafe { &mut *(s as *mut T).cast::<[T; 1]>() }
 }
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 58a170401e7..63c42068aad 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -136,6 +136,8 @@
 #![feature(ptr_metadata)]
 #![feature(slice_ptr_get)]
 #![feature(variant_count)]
+#![feature(const_array_from_ref)]
+#![feature(const_slice_from_ref)]
 //
 // Language features:
 #![feature(abi_unadjusted)]
diff --git a/library/core/src/slice/raw.rs b/library/core/src/slice/raw.rs
index eda50dc287f..ad38aaf9f83 100644
--- a/library/core/src/slice/raw.rs
+++ b/library/core/src/slice/raw.rs
@@ -138,12 +138,14 @@ pub unsafe fn from_raw_parts_mut<'a, T>(data: *mut T, len: usize) -> &'a mut [T]
 
 /// Converts a reference to T into a slice of length 1 (without copying).
 #[stable(feature = "from_ref", since = "1.28.0")]
-pub fn from_ref<T>(s: &T) -> &[T] {
+#[rustc_const_unstable(feature = "const_slice_from_ref", issue = "90206")]
+pub const fn from_ref<T>(s: &T) -> &[T] {
     array::from_ref(s)
 }
 
 /// Converts a reference to T into a slice of length 1 (without copying).
 #[stable(feature = "from_ref", since = "1.28.0")]
-pub fn from_mut<T>(s: &mut T) -> &mut [T] {
+#[rustc_const_unstable(feature = "const_slice_from_ref", issue = "90206")]
+pub const fn from_mut<T>(s: &mut T) -> &mut [T] {
     array::from_mut(s)
 }
diff --git a/library/core/tests/array.rs b/library/core/tests/array.rs
index 1d4307ca0fb..7dc071b7423 100644
--- a/library/core/tests/array.rs
+++ b/library/core/tests/array.rs
@@ -7,6 +7,11 @@ fn array_from_ref() {
     let value: String = "Hello World!".into();
     let arr: &[String; 1] = array::from_ref(&value);
     assert_eq!(&[value.clone()], arr);
+
+    const VALUE: &&str = &"Hello World!";
+    const ARR: &[&str; 1] = array::from_ref(VALUE);
+    assert_eq!(&[*VALUE], ARR);
+    assert!(core::ptr::eq(VALUE, &ARR[0]));
 }
 
 #[test]
diff --git a/library/core/tests/lib.rs b/library/core/tests/lib.rs
index 507a79c3de1..e1ba5020a50 100644
--- a/library/core/tests/lib.rs
+++ b/library/core/tests/lib.rs
@@ -74,6 +74,8 @@
 #![feature(trusted_random_access)]
 #![feature(unsize)]
 #![feature(unzip_option)]
+#![feature(const_array_from_ref)]
+#![feature(const_slice_from_ref)]
 #![deny(unsafe_op_in_unsafe_fn)]
 
 extern crate test;
diff --git a/library/core/tests/slice.rs b/library/core/tests/slice.rs
index 7a008345243..8d05e47edf4 100644
--- a/library/core/tests/slice.rs
+++ b/library/core/tests/slice.rs
@@ -2147,6 +2147,14 @@ fn test_slice_run_destructors() {
 }
 
 #[test]
+fn test_const_from_ref() {
+    const VALUE: &i32 = &1;
+    const SLICE: &[i32] = core::slice::from_ref(VALUE);
+
+    assert!(core::ptr::eq(VALUE, &SLICE[0]))
+}
+
+#[test]
 fn test_slice_fill_with_uninit() {
     // This should not UB. See #87891
     let mut a = [MaybeUninit::<u8>::uninit(); 10];
diff --git a/library/std/src/collections/hash/map.rs b/library/std/src/collections/hash/map.rs
index 01019344f4f..d36a3eaea92 100644
--- a/library/std/src/collections/hash/map.rs
+++ b/library/std/src/collections/hash/map.rs
@@ -414,6 +414,7 @@ impl<K, V, S> HashMap<K, V, S> {
     ///     println!("key: {} val: {}", key, val);
     /// }
     /// ```
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn iter(&self) -> Iter<'_, K, V> {
         Iter { base: self.base.iter() }
@@ -442,6 +443,7 @@ impl<K, V, S> HashMap<K, V, S> {
     ///     println!("key: {} val: {}", key, val);
     /// }
     /// ```
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn iter_mut(&mut self) -> IterMut<'_, K, V> {
         IterMut { base: self.base.iter_mut() }
@@ -502,6 +504,7 @@ impl<K, V, S> HashMap<K, V, S> {
     /// assert!(a.is_empty());
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "drain", since = "1.6.0")]
     pub fn drain(&mut self) -> Drain<'_, K, V> {
         Drain { base: self.base.drain() }
@@ -543,6 +546,7 @@ impl<K, V, S> HashMap<K, V, S> {
     /// assert_eq!(odds, vec![1, 3, 5, 7]);
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[unstable(feature = "hash_drain_filter", issue = "59618")]
     pub fn drain_filter<F>(&mut self, pred: F) -> DrainFilter<'_, K, V, F>
     where
@@ -949,6 +953,7 @@ where
     /// assert_eq!(map.len(), 4);
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "retain_hash_collection", since = "1.18.0")]
     pub fn retain<F>(&mut self, f: F)
     where
@@ -978,6 +983,7 @@ where
     /// assert_eq!(vec, ["a", "b", "c"]);
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "map_into_keys_values", since = "1.54.0")]
     pub fn into_keys(self) -> IntoKeys<K, V> {
         IntoKeys { inner: self.into_iter() }
@@ -1004,6 +1010,7 @@ where
     /// assert_eq!(vec, [1, 2, 3]);
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "map_into_keys_values", since = "1.54.0")]
     pub fn into_values(self) -> IntoValues<K, V> {
         IntoValues { inner: self.into_iter() }
@@ -1969,6 +1976,7 @@ impl<'a, K, V, S> IntoIterator for &'a HashMap<K, V, S> {
     type IntoIter = Iter<'a, K, V>;
 
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     fn into_iter(self) -> Iter<'a, K, V> {
         self.iter()
     }
@@ -1980,6 +1988,7 @@ impl<'a, K, V, S> IntoIterator for &'a mut HashMap<K, V, S> {
     type IntoIter = IterMut<'a, K, V>;
 
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     fn into_iter(self) -> IterMut<'a, K, V> {
         self.iter_mut()
     }
@@ -2008,6 +2017,7 @@ impl<K, V, S> IntoIterator for HashMap<K, V, S> {
     /// let vec: Vec<(&str, i32)> = map.into_iter().collect();
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     fn into_iter(self) -> IntoIter<K, V> {
         IntoIter { base: self.base.into_iter() }
     }
diff --git a/library/std/src/collections/hash/set.rs b/library/std/src/collections/hash/set.rs
index 546c43faecf..76008e565b3 100644
--- a/library/std/src/collections/hash/set.rs
+++ b/library/std/src/collections/hash/set.rs
@@ -185,6 +185,7 @@ impl<T, S> HashSet<T, S> {
     /// }
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn iter(&self) -> Iter<'_, T> {
         Iter { base: self.base.iter() }
@@ -244,6 +245,7 @@ impl<T, S> HashSet<T, S> {
     /// assert!(set.is_empty());
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "drain", since = "1.6.0")]
     pub fn drain(&mut self) -> Drain<'_, T> {
         Drain { base: self.base.drain() }
@@ -282,6 +284,7 @@ impl<T, S> HashSet<T, S> {
     /// assert_eq!(odds, vec![1, 3, 5, 7]);
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[unstable(feature = "hash_drain_filter", issue = "59618")]
     pub fn drain_filter<F>(&mut self, pred: F) -> DrainFilter<'_, T, F>
     where
@@ -506,6 +509,7 @@ where
     /// assert_eq!(diff, [4].iter().collect());
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn difference<'a>(&'a self, other: &'a HashSet<T, S>) -> Difference<'a, T, S> {
         Difference { iter: self.iter(), other }
@@ -533,6 +537,7 @@ where
     /// assert_eq!(diff1, [1, 4].iter().collect());
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn symmetric_difference<'a>(
         &'a self,
@@ -560,6 +565,7 @@ where
     /// assert_eq!(intersection, [2, 3].iter().collect());
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn intersection<'a>(&'a self, other: &'a HashSet<T, S>) -> Intersection<'a, T, S> {
         if self.len() <= other.len() {
@@ -588,6 +594,7 @@ where
     /// assert_eq!(union, [1, 2, 3, 4].iter().collect());
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn union<'a>(&'a self, other: &'a HashSet<T, S>) -> Union<'a, T, S> {
         if self.len() >= other.len() {
@@ -922,6 +929,7 @@ where
     /// set.retain(|&k| k % 2 == 0);
     /// assert_eq!(set.len(), 3);
     /// ```
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     #[stable(feature = "retain_hash_collection", since = "1.18.0")]
     pub fn retain<F>(&mut self, f: F)
     where
@@ -1403,6 +1411,7 @@ impl<'a, T, S> IntoIterator for &'a HashSet<T, S> {
     type IntoIter = Iter<'a, T>;
 
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     fn into_iter(self) -> Iter<'a, T> {
         self.iter()
     }
@@ -1434,6 +1443,7 @@ impl<T, S> IntoIterator for HashSet<T, S> {
     /// }
     /// ```
     #[inline]
+    #[cfg_attr(not(bootstrap), rustc_lint_query_instability)]
     fn into_iter(self) -> IntoIter<T> {
         IntoIter { base: self.base.into_iter() }
     }