Rollup of 11 pull requests

compiler/rustc_feature/src/active.rs

@@ -678,6 +678,9 @@ declare_features! (
     /// Allows `#[doc(cfg_hide(...))]`.
     (active, doc_cfg_hide, "1.57.0", Some(43781), None),
 
+    /// Allows using the `non_exhaustive_omitted_patterns` lint.
+    (active, non_exhaustive_omitted_patterns_lint, "1.57.0", Some(89554), None),
+
     // -------------------------------------------------------------------------
     // feature-group-end: actual feature gates
     // -------------------------------------------------------------------------

compiler/rustc_lint_defs/src/builtin.rs

@@ -6,6 +6,7 @@
 
 use crate::{declare_lint, declare_lint_pass, FutureIncompatibilityReason};
 use rustc_span::edition::Edition;
+use rustc_span::symbol::sym;
 
 declare_lint! {
     /// The `forbidden_lint_groups` lint detects violations of
@@ -3476,6 +3477,8 @@ declare_lint! {
     /// }
     ///
     /// // in crate B
+    /// #![feature(non_exhaustive_omitted_patterns_lint)]
+    ///
     /// match Bar::A {
     ///     Bar::A => {},
     ///     #[warn(non_exhaustive_omitted_patterns)]
@@ -3512,6 +3515,7 @@ declare_lint! {
     pub NON_EXHAUSTIVE_OMITTED_PATTERNS,
     Allow,
     "detect when patterns of types marked `non_exhaustive` are missed",
+    @feature_gate = sym::non_exhaustive_omitted_patterns_lint;
 }
 
 declare_lint! {

compiler/rustc_span/src/symbol.rs

@@ -893,6 +893,7 @@ symbols! {
         nomem,
         non_ascii_idents,
         non_exhaustive,
+        non_exhaustive_omitted_patterns_lint,
         non_modrs_mods,
         none_error,
         nontemporal_store,

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

@@ -534,6 +534,7 @@ impl<T> BTreeSet<T> {
     /// b.insert(1);
     /// assert_eq!(a.is_disjoint(&b), false);
     /// ```
+    #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn is_disjoint(&self, other: &BTreeSet<T>) -> bool
     where
@@ -559,6 +560,7 @@ impl<T> BTreeSet<T> {
     /// set.insert(4);
     /// assert_eq!(set.is_subset(&sup), false);
     /// ```
+    #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn is_subset(&self, other: &BTreeSet<T>) -> bool
     where
@@ -638,6 +640,7 @@ impl<T> BTreeSet<T> {
     /// set.insert(2);
     /// assert_eq!(set.is_superset(&sub), true);
     /// ```
+    #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn is_superset(&self, other: &BTreeSet<T>) -> bool
     where

library/alloc/src/lib.rs

@@ -73,6 +73,7 @@
         not(test),
         not(any(test, bootstrap)),
         any(not(feature = "miri-test-libstd"), test, doctest),
+        no_global_oom_handling,
         target_has_atomic = "ptr"
     ))
 )]

library/core/src/cell.rs

@@ -349,7 +349,7 @@ impl<T> Cell<T> {
         drop(old);
     }
 
-    /// Swaps the values of two Cells.
+    /// Swaps the values of two `Cell`s.
     /// Difference with `std::mem::swap` is that this function doesn't require `&mut` reference.
     ///
     /// # Examples

library/core/src/char/methods.rs

@@ -377,6 +377,8 @@ impl char {
     /// ```
     /// assert_eq!('❤'.escape_unicode().to_string(), "\\u{2764}");
     /// ```
+    #[must_use = "this returns the escaped char as an iterator, \
+                  without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn escape_unicode(self) -> EscapeUnicode {
@@ -453,6 +455,8 @@ impl char {
     /// ```
     /// assert_eq!('\n'.escape_debug().to_string(), "\\n");
     /// ```
+    #[must_use = "this returns the escaped char as an iterator, \
+                  without modifying the original"]
     #[stable(feature = "char_escape_debug", since = "1.20.0")]
     #[inline]
     pub fn escape_debug(self) -> EscapeDebug {
@@ -507,6 +511,8 @@ impl char {
     /// ```
     /// assert_eq!('"'.escape_default().to_string(), "\\\"");
     /// ```
+    #[must_use = "this returns the escaped char as an iterator, \
+                  without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn escape_default(self) -> EscapeDefault {
@@ -692,6 +698,7 @@ impl char {
     /// // love is many things, but it is not alphabetic
     /// assert!(!c.is_alphabetic());
     /// ```
+    #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is_alphabetic(self) -> bool {
@@ -724,6 +731,7 @@ impl char {
     /// assert!(!'中'.is_lowercase());
     /// assert!(!' '.is_lowercase());
     /// ```
+    #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is_lowercase(self) -> bool {
@@ -756,6 +764,7 @@ impl char {
     /// assert!(!'中'.is_uppercase());
     /// assert!(!' '.is_uppercase());
     /// ```
+    #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is_uppercase(self) -> bool {
@@ -784,6 +793,7 @@ impl char {
     ///
     /// assert!(!'越'.is_whitespace());
     /// ```
+    #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is_whitespace(self) -> bool {
@@ -812,6 +822,7 @@ impl char {
     /// assert!('و'.is_alphanumeric());
     /// assert!('藏'.is_alphanumeric());
     /// ```
+    #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is_alphanumeric(self) -> bool {
@@ -837,6 +848,7 @@ impl char {
     /// assert!('œ'.is_control());
     /// assert!(!'q'.is_control());
     /// ```
+    #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is_control(self) -> bool {
@@ -852,6 +864,7 @@ impl char {
     /// [uax29]: https://www.unicode.org/reports/tr29/
     /// [ucd]: https://www.unicode.org/reports/tr44/
     /// [`DerivedCoreProperties.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/DerivedCoreProperties.txt
+    #[must_use]
     #[inline]
     pub(crate) fn is_grapheme_extended(self) -> bool {
         unicode::Grapheme_Extend(self)
@@ -881,6 +894,7 @@ impl char {
     /// assert!(!'و'.is_numeric());
     /// assert!(!'藏'.is_numeric());
     /// ```
+    #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is_numeric(self) -> bool {
@@ -1060,6 +1074,7 @@ impl char {
     /// assert!(ascii.is_ascii());
     /// assert!(!non_ascii.is_ascii());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
     #[rustc_const_stable(feature = "const_ascii_methods_on_intrinsics", since = "1.32.0")]
     #[inline]
@@ -1237,6 +1252,7 @@ impl char {
     /// assert!(!lf.is_ascii_alphabetic());
     /// assert!(!esc.is_ascii_alphabetic());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
     #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
     #[inline]
@@ -1270,6 +1286,7 @@ impl char {
     /// assert!(!lf.is_ascii_uppercase());
     /// assert!(!esc.is_ascii_uppercase());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
     #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
     #[inline]
@@ -1303,6 +1320,7 @@ impl char {
     /// assert!(!lf.is_ascii_lowercase());
     /// assert!(!esc.is_ascii_lowercase());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
     #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
     #[inline]
@@ -1339,6 +1357,7 @@ impl char {
     /// assert!(!lf.is_ascii_alphanumeric());
     /// assert!(!esc.is_ascii_alphanumeric());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
     #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
     #[inline]
@@ -1372,6 +1391,7 @@ impl char {
     /// assert!(!lf.is_ascii_digit());
     /// assert!(!esc.is_ascii_digit());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
     #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
     #[inline]
@@ -1408,6 +1428,7 @@ impl char {
     /// assert!(!lf.is_ascii_hexdigit());
     /// assert!(!esc.is_ascii_hexdigit());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
     #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
     #[inline]
@@ -1445,6 +1466,7 @@ impl char {
     /// assert!(!lf.is_ascii_punctuation());
     /// assert!(!esc.is_ascii_punctuation());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
     #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
     #[inline]
@@ -1478,6 +1500,7 @@ impl char {
     /// assert!(!lf.is_ascii_graphic());
     /// assert!(!esc.is_ascii_graphic());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
     #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
     #[inline]
@@ -1528,6 +1551,7 @@ impl char {
     /// assert!(lf.is_ascii_whitespace());
     /// assert!(!esc.is_ascii_whitespace());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
     #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
     #[inline]
@@ -1563,6 +1587,7 @@ impl char {
     /// assert!(lf.is_ascii_control());
     /// assert!(esc.is_ascii_control());
     /// ```
+    #[must_use]
     #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
     #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
     #[inline]

library/core/src/hash/mod.rs

@@ -153,9 +153,21 @@ mod sip;
 /// Thankfully, you won't need to worry about upholding this property when
 /// deriving both [`Eq`] and `Hash` with `#[derive(PartialEq, Eq, Hash)]`.
 ///
+/// ## Prefix collisions
+///
+/// Implementations of `hash` should ensure that the data they
+/// pass to the `Hasher` are prefix-free. That is,
+/// unequal values should cause two different sequences of values to be written,
+/// and neither of the two sequences should be a prefix of the other.
+///
+/// For example, the standard implementation of [`Hash` for `&str`][impl] passes an extra
+/// `0xFF` byte to the `Hasher` so that the values `("ab", "c")` and `("a",
+/// "bc")` hash differently.
+///
 /// [`HashMap`]: ../../std/collections/struct.HashMap.html
 /// [`HashSet`]: ../../std/collections/struct.HashSet.html
 /// [`hash`]: Hash::hash
+/// [impl]: ../../std/primitive.str.html#impl-Hash
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Hash"]
 pub trait Hash {

library/core/src/lib.rs

@@ -65,6 +65,7 @@
     doc(cfg_hide(
         not(test),
         any(not(feature = "miri-test-libstd"), test, doctest),
+        no_fp_fmt_parse,
         target_pointer_width = "16",
         target_pointer_width = "32",
         target_pointer_width = "64",