Auto merge of #88750 - jackh726:rollup-w57i9fp, r=jackh726

Rollup of 9 pull requests

Successful merges:

 - #86263 (Rustdoc: Report Layout of enum variants)
 - #88541 (Add regression test for #74400)
 - #88553 (Improve diagnostics for unary plus operators (#88276))
 - #88594 (More symbolic doc aliases)
 - #88648 (Correct “copies” to “moves” in `<Option<T> as From<T>>::from` doc, and other copyediting)
 - #88691 (Add a regression test for #88649)
 - #88694 (Drop 1.56 stabilizations from 1.55 release notes)
 - #88712 (Fix docs for `uX::checked_next_multiple_of`)
 - #88726 (Fix typo in `const_generics` replaced with `adt_const_params` note)

Failed merges:

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

RELEASES.md

@@ -10,8 +10,7 @@ Language
 
 Compiler
 --------
-- [Added tier 3\* support for `powerpc-unknown-freebsd`.][87370]
-- [Added tier 3 support for `powerpc64le-unknown-freebsd`.][83572]
+- [Added tier 3\* support for `powerpc64le-unknown-freebsd`.][83572]
 
 \* Refer to Rust's [platform support page][platform-support-doc] for more
    information on Rust's tiered platform support.
@@ -24,17 +23,6 @@ Libraries
   no longer reject certain valid floating point values, and reduce
   the produced code size for non-stripped artifacts.
 - [`string::Drain` now implements `AsRef<str>` and `AsRef<[u8]>`.][86858]
-- [`collections::{BinaryHeap, BTreeSet, HashSet, LinkedList, VecDeque}` now
-  implement `From<[T; N]>`.][84111]
-- [`collections::{BTreeMap, HashMap}` now implement `From<[(K, V); N]>`.][84111]
-  This allows you to write the following;
-  ```rust
-  let highscores = std::collections::HashMap::from([
-      ("Alice", 9000u32),
-      ("Bob", 7250),
-      ("Charlie", 5500),
-  ]);
-  ```
 
 Stabilised APIs
 ---------------
@@ -60,7 +48,6 @@ Stabilised APIs
 The following previously stable functions are now `const`.
 
 - [`str::from_utf8_unchecked`]
-- [`mem::transmute`]
 
 
 Cargo
@@ -131,7 +118,6 @@ Compatibility Notes
 [`MaybeUninit::assume_init_ref`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init_ref
 [`MaybeUninit::write`]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.write
 [`Seek::rewind`]: https://doc.rust-lang.org/stable/std/io/trait.Seek.html#method.rewind
-[`mem::transmute`]: https://doc.rust-lang.org/stable/std/mem/fn.transmute.html
 [`ops::ControlFlow`]: https://doc.rust-lang.org/stable/std/ops/enum.ControlFlow.html
 [`str::from_utf8_unchecked`]: https://doc.rust-lang.org/stable/std/str/fn.from_utf8_unchecked.html
 [`x86::_bittest`]: https://doc.rust-lang.org/stable/core/arch/x86/fn._bittest.html

compiler/rustc_ast/src/token.rs

@@ -586,6 +586,13 @@ impl Token {
         self.is_non_raw_ident_where(|id| id.name.is_bool_lit())
     }
 
+    pub fn is_numeric_lit(&self) -> bool {
+        matches!(
+            self.kind,
+            Literal(Lit { kind: LitKind::Integer, .. }) | Literal(Lit { kind: LitKind::Float, .. })
+        )
+    }
+
     /// Returns `true` if the token is a non-raw identifier for which `pred` holds.
     pub fn is_non_raw_ident_where(&self, pred: impl FnOnce(Ident) -> bool) -> bool {
         match self.ident() {

compiler/rustc_feature/src/removed.rs

@@ -104,7 +104,7 @@ declare_features! (
     (removed, quote, "1.33.0", Some(29601), None, None),
     /// Allows const generic types (e.g. `struct Foo<const N: usize>(...);`).
     (removed, const_generics, "1.34.0", Some(44580), None,
-     Some("removed in favor of `#![feature(adt_const_params]` and `#![feature(generic_const_exprs)]`")),
+     Some("removed in favor of `#![feature(adt_const_params)]` and `#![feature(generic_const_exprs)]`")),
     /// Allows `[x; N]` where `x` is a constant (RFC 2203).
     (removed, const_in_array_repeat_expressions,  "1.37.0", Some(49147), None,
      Some("removed due to causing promotable bugs")),

compiler/rustc_parse/src/parser/expr.rs

@@ -516,6 +516,26 @@ impl<'a> Parser<'a> {
             token::BinOp(token::And) | token::AndAnd => {
                 make_it!(this, attrs, |this, _| this.parse_borrow_expr(lo))
             }
+            token::BinOp(token::Plus) if this.look_ahead(1, |tok| tok.is_numeric_lit()) => {
+                let mut err = this.struct_span_err(lo, "leading `+` is not supported");
+                err.span_label(lo, "unexpected `+`");
+
+                // a block on the LHS might have been intended to be an expression instead
+                if let Some(sp) = this.sess.ambiguous_block_expr_parse.borrow().get(&lo) {
+                    this.sess.expr_parentheses_needed(&mut err, *sp);
+                } else {
+                    err.span_suggestion_verbose(
+                        lo,
+                        "try removing the `+`",
+                        "".to_string(),
+                        Applicability::MachineApplicable,
+                    );
+                }
+                err.emit();
+
+                this.bump();
+                this.parse_prefix_expr(None)
+            } // `+expr`
             token::Ident(..) if this.token.is_keyword(kw::Box) => {
                 make_it!(this, attrs, |this, _| this.parse_box_expr(lo))
             }

library/core/src/num/uint_macros.rs

@@ -1924,7 +1924,8 @@ macro_rules! uint_impl {
         }
 
         /// Calculates the smallest value greater than or equal to `self` that
-        /// is a multiple of `rhs`. If `rhs` is negative,
+        /// is a multiple of `rhs`. Returns `None` is `rhs` is zero or the
+        /// operation would result in overflow.
         ///
         /// # Examples
         ///

library/core/src/ops/bit.rs

@@ -30,6 +30,7 @@
 /// ```
 #[lang = "not"]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[doc(alias = "!")]
 pub trait Not {
     /// The resulting type after applying the `!` operator.
     #[stable(feature = "rust1", since = "1.0.0")]

library/core/src/option.rs

@@ -1173,7 +1173,7 @@ impl<T> Option<T> {
     // Entry-like operations to insert a value and return a reference
     /////////////////////////////////////////////////////////////////////////
 
-    /// Inserts `value` into the option then returns a mutable reference to it.
+    /// Inserts `value` into the option, then returns a mutable reference to it.
     ///
     /// If the option already contains a value, the old value is dropped.
     ///
@@ -1397,7 +1397,7 @@ impl<T> Option<T> {
 }
 
 impl<T, U> Option<(T, U)> {
-    /// Unzips an option containing a tuple of two options
+    /// Unzips an option containing a tuple of two options.
     ///
     /// If `self` is `Some((a, b))` this method returns `(Some(a), Some(b))`.
     /// Otherwise, `(None, None)` is returned.
@@ -1500,7 +1500,7 @@ impl<T: Clone> Option<&mut T> {
 }
 
 impl<T: Default> Option<T> {
-    /// Returns the contained [`Some`] value or a default
+    /// Returns the contained [`Some`] value or a default.
     ///
     /// Consumes the `self` argument then, if [`Some`], returns the contained
     /// value, otherwise if [`None`], returns the [default value] for that
@@ -1561,7 +1561,7 @@ impl<T: DerefMut> Option<T> {
     /// Converts from `Option<T>` (or `&mut Option<T>`) to `Option<&mut T::Target>`.
     ///
     /// Leaves the original `Option` in-place, creating a new one containing a mutable reference to
-    /// the inner type's `Deref::Target` type.
+    /// the inner type's [`Deref::Target`] type.
     ///
     /// # Examples
     ///
@@ -1701,7 +1701,7 @@ impl<'a, T> IntoIterator for &'a mut Option<T> {
 
 #[stable(since = "1.12.0", feature = "option_from")]
 impl<T> From<T> for Option<T> {
-    /// Copies `val` into a new `Some`.
+    /// Moves `val` into a new [`Some`].
     ///
     /// # Examples
     ///
@@ -1942,8 +1942,8 @@ unsafe impl<A> TrustedLen for IntoIter<A> {}
 impl<A, V: FromIterator<A>> FromIterator<Option<A>> for Option<V> {
     /// Takes each element in the [`Iterator`]: if it is [`None`][Option::None],
     /// no further elements are taken, and the [`None`][Option::None] is
-    /// returned. Should no [`None`][Option::None] occur, a container with the
-    /// values of each [`Option`] is returned.
+    /// returned. Should no [`None`][Option::None] occur, a container of type
+    /// `V` containing the values of each [`Option`] is returned.
     ///
     /// # Examples
     ///
@@ -2039,7 +2039,7 @@ impl<T> ops::FromResidual for Option<T> {
 }
 
 impl<T> Option<Option<T>> {
-    /// Converts from `Option<Option<T>>` to `Option<T>`
+    /// Converts from `Option<Option<T>>` to `Option<T>`.
     ///
     /// # Examples
     ///

library/std/src/keyword_docs.rs

@@ -119,7 +119,7 @@ mod break_keyword {}
 
 #[doc(keyword = "const")]
 //
-/// Compile-time constants and compile-time evaluable functions.
+/// Compile-time constants, compile-time evaluable functions, and raw pointers.
 ///
 /// ## Compile-time constants
 ///

library/std/src/primitive_docs.rs

@@ -388,8 +388,11 @@ mod prim_char {}
 #[stable(feature = "rust1", since = "1.0.0")]
 mod prim_unit {}
 
-#[doc(alias = "ptr")]
 #[doc(primitive = "pointer")]
+#[doc(alias = "ptr")]
+#[doc(alias = "*")]
+#[doc(alias = "*const")]
+#[doc(alias = "*mut")]
 //
 /// Raw, unsafe pointers, `*const T`, and `*mut T`.
 ///
@@ -502,10 +505,10 @@ mod prim_unit {}
 #[stable(feature = "rust1", since = "1.0.0")]
 mod prim_pointer {}
 
+#[doc(primitive = "array")]
 #[doc(alias = "[]")]
 #[doc(alias = "[T;N]")] // unfortunately, rustdoc doesn't have fuzzy search for aliases
 #[doc(alias = "[T; N]")]
-#[doc(primitive = "array")]
 /// A fixed-size array, denoted `[T; N]`, for the element type, `T`, and the
 /// non-negative compile-time constant size, `N`.
 ///

src/librustdoc/html/render/print_item.rs

@@ -8,10 +8,12 @@ use rustc_hir as hir;
 use rustc_hir::def::CtorKind;
 use rustc_hir::def_id::DefId;
 use rustc_middle::middle::stability;
+use rustc_middle::span_bug;
 use rustc_middle::ty::layout::LayoutError;
-use rustc_middle::ty::TyCtxt;
+use rustc_middle::ty::{Adt, TyCtxt};
 use rustc_span::hygiene::MacroKind;
 use rustc_span::symbol::{kw, sym, Symbol};
+use rustc_target::abi::{Layout, Primitive, TagEncoding, Variants};
 
 use super::{
     collect_paths_for_type, document, ensure_trailing_slash, item_ty_to_strs, notable_traits_decl,
@@ -1621,6 +1623,15 @@ fn document_non_exhaustive(w: &mut Buffer, item: &clean::Item) {
 }
 
 fn document_type_layout(w: &mut Buffer, cx: &Context<'_>, ty_def_id: DefId) {
+    fn write_size_of_layout(w: &mut Buffer, layout: &Layout, tag_size: u64) {
+        if layout.abi.is_unsized() {
+            write!(w, "(unsized)");
+        } else {
+            let bytes = layout.size.bytes() - tag_size;
+            write!(w, "{size} byte{pl}", size = bytes, pl = if bytes == 1 { "" } else { "s" },);
+        }
+    }
+
     if !cx.shared.show_type_layout {
         return;
     }
@@ -1642,16 +1653,40 @@ fn document_type_layout(w: &mut Buffer, cx: &Context<'_>, ty_def_id: DefId) {
                  <a href=\"https://doc.rust-lang.org/reference/type-layout.html\">“Type Layout”</a> \
                  chapter for details on type layout guarantees.</p></div>"
             );
-            if ty_layout.layout.abi.is_unsized() {
-                writeln!(w, "<p><strong>Size:</strong> (unsized)</p>");
-            } else {
-                let bytes = ty_layout.layout.size.bytes();
-                writeln!(
-                    w,
-                    "<p><strong>Size:</strong> {size} byte{pl}</p>",
-                    size = bytes,
-                    pl = if bytes == 1 { "" } else { "s" },
-                );
+            w.write_str("<p><strong>Size:</strong> ");
+            write_size_of_layout(w, ty_layout.layout, 0);
+            writeln!(w, "</p>");
+            if let Variants::Multiple { variants, tag, tag_encoding, .. } =
+                &ty_layout.layout.variants
+            {
+                if !variants.is_empty() {
+                    w.write_str(
+                        "<p><strong>Size for each variant:</strong></p>\
+                            <ul>",
+                    );
+
+                    let adt = if let Adt(adt, _) = ty_layout.ty.kind() {
+                        adt
+                    } else {
+                        span_bug!(tcx.def_span(ty_def_id), "not an adt")
+                    };
+
+                    let tag_size = if let TagEncoding::Niche { .. } = tag_encoding {
+                        0
+                    } else if let Primitive::Int(i, _) = tag.value {
+                        i.size().bytes()
+                    } else {
+                        span_bug!(tcx.def_span(ty_def_id), "tag is neither niche nor int")
+                    };
+
+                    for (index, layout) in variants.iter_enumerated() {
+                        let ident = adt.variants[index].ident;
+                        write!(w, "<li><code>{name}</code>: ", name = ident);
+                        write_size_of_layout(w, layout, tag_size);
+                        writeln!(w, "</li>");
+                    }
+                    w.write_str("</ul>");
+                }
             }
         }
         // This kind of layout error can occur with valid code, e.g. if you try to

src/test/rustdoc/type-layout.rs

@@ -52,3 +52,21 @@ pub struct Unsized([u8]);
 
 // @!has type_layout/trait.MyTrait.html 'Size: '
 pub trait MyTrait {}
+
+// @has type_layout/enum.Variants.html 'Size: '
+// @has - '2 bytes'
+// @has - '<code>A</code>: 0 bytes'
+// @has - '<code>B</code>: 1 byte'
+pub enum Variants {
+    A,
+    B(u8),
+}
+
+// @has type_layout/enum.WithNiche.html 'Size: '
+// @has - //p '4 bytes'
+// @has - '<code>None</code>: 0 bytes'
+// @has - '<code>Some</code>: 4 bytes'
+pub enum WithNiche {
+    None,
+    Some(std::num::NonZeroU32),
+}

src/test/ui/associated-types/issue-36499.stderr

@@ -1,8 +1,14 @@
-error: expected expression, found `+`
+error: leading `+` is not supported
   --> $DIR/issue-36499.rs:4:9
    |
 LL |     2 + +2;
-   |         ^ expected expression
+   |         ^ unexpected `+`
+   |
+help: try removing the `+`
+   |
+LL -     2 + +2;
+LL +     2 + 2;
+   | 
 
 error: aborting due to previous error
 

src/test/ui/consts/issue-88649.rs

@@ -0,0 +1,18 @@
+// check-pass
+#![crate_type = "lib"]
+
+enum Foo {
+    Variant1(bool),
+    Variant2(bool),
+}
+
+const _: () = {
+    let mut n = 0;
+    while n < 2 {
+        match Foo::Variant1(true) {
+            Foo::Variant1(x) | Foo::Variant2(x) if x => {}
+            _ => {}
+        }
+        n += 1;
+    }
+};

src/test/ui/lifetimes/lifetime-errors/issue_74400.nll.stderr

@@ -0,0 +1,30 @@
+error[E0310]: the parameter type `T` may not live long enough
+  --> $DIR/issue_74400.rs:12:5
+   |
+LL |     f(data, identity)
+   |     ^^^^^^^^^^^^^^^^^
+   |
+   = help: consider adding an explicit lifetime bound `T: 'static`...
+
+error[E0308]: mismatched types
+  --> $DIR/issue_74400.rs:12:5
+   |
+LL |     f(data, identity)
+   |     ^^^^^^^^^^^^^^^^^ one type is more general than the other
+   |
+   = note: expected type `for<'r> Fn<(&'r T,)>`
+              found type `Fn<(&T,)>`
+
+error: implementation of `FnOnce` is not general enough
+  --> $DIR/issue_74400.rs:12:5
+   |
+LL |     f(data, identity)
+   |     ^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
+   |
+   = note: `fn(&'2 T) -> &'2 T {identity::<&'2 T>}` must implement `FnOnce<(&'1 T,)>`, for any lifetime `'1`...
+   = note: ...but it actually implements `FnOnce<(&'2 T,)>`, for some specific lifetime `'2`
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0308, E0310.
+For more information about an error, try `rustc --explain E0308`.

src/test/ui/lifetimes/lifetime-errors/issue_74400.rs

@@ -0,0 +1,13 @@
+//! Regression test for #74400: Type mismatch in function arguments E0631, E0271 are falsely
+//! recognized as E0308 mismatched types.
+
+use std::convert::identity;
+
+fn main() {}
+
+fn f<T, S>(data: &[T], key: impl Fn(&T) -> S) {
+}
+
+fn g<T>(data: &[T]) {
+    f(data, identity) //~ ERROR implementation of `FnOnce` is not general
+}

src/test/ui/lifetimes/lifetime-errors/issue_74400.stderr

@@ -0,0 +1,11 @@
+error: implementation of `FnOnce` is not general enough
+  --> $DIR/issue_74400.rs:12:5
+   |
+LL |     f(data, identity)
+   |     ^ implementation of `FnOnce` is not general enough
+   |
+   = note: `fn(&'2 T) -> &'2 T {identity::<&'2 T>}` must implement `FnOnce<(&'1 T,)>`, for any lifetime `'1`...
+   = note: ...but it actually implements `FnOnce<(&'2 T,)>`, for some specific lifetime `'2`
+
+error: aborting due to previous error
+

src/test/ui/parser/expr-as-stmt.fixed

@@ -10,7 +10,7 @@ fn foo() -> i32 {
 }
 
 fn bar() -> i32 {
-    ({2}) + 2 //~ ERROR expected expression, found `+`
+    ({2}) + 2 //~ ERROR leading `+` is not supported
     //~^ ERROR mismatched types
 }
 

src/test/ui/parser/expr-as-stmt.rs

@@ -10,7 +10,7 @@ fn foo() -> i32 {
 }
 
 fn bar() -> i32 {
-    {2} + 2 //~ ERROR expected expression, found `+`
+    {2} + 2 //~ ERROR leading `+` is not supported
     //~^ ERROR mismatched types
 }
 

src/test/ui/parser/expr-as-stmt.stderr

@@ -9,11 +9,11 @@ help: parentheses are required to parse this as an expression
 LL |     ({2}) + {2}
    |     +   +
 
-error: expected expression, found `+`
+error: leading `+` is not supported
   --> $DIR/expr-as-stmt.rs:13:9
    |
 LL |     {2} + 2
-   |         ^ expected expression
+   |         ^ unexpected `+`
    |
 help: parentheses are required to parse this as an expression
    |

src/test/ui/parser/issue-88276-unary-plus.fixed

@@ -0,0 +1,8 @@
+// run-rustfix
+#[allow(unused_parens)]
+fn main() {
+    let _ = 1; //~ ERROR leading `+` is not supported
+    let _ = (1.0 + 2.0) * 3.0; //~ ERROR leading `+` is not supported
+                           //~| ERROR leading `+` is not supported
+    let _ = [3, 4+6]; //~ ERROR leading `+` is not supported
+}

src/test/ui/parser/issue-88276-unary-plus.rs

@@ -0,0 +1,8 @@
+// run-rustfix
+#[allow(unused_parens)]
+fn main() {
+    let _ = +1; //~ ERROR leading `+` is not supported
+    let _ = (1.0 + +2.0) * +3.0; //~ ERROR leading `+` is not supported
+                           //~| ERROR leading `+` is not supported
+    let _ = [+3, 4+6]; //~ ERROR leading `+` is not supported
+}

src/test/ui/parser/issue-88276-unary-plus.stderr

@@ -0,0 +1,50 @@
+error: leading `+` is not supported
+  --> $DIR/issue-88276-unary-plus.rs:4:13
+   |
+LL |     let _ = +1;
+   |             ^ unexpected `+`
+   |
+help: try removing the `+`
+   |
+LL -     let _ = +1;
+LL +     let _ = 1;
+   | 
+
+error: leading `+` is not supported
+  --> $DIR/issue-88276-unary-plus.rs:5:20
+   |
+LL |     let _ = (1.0 + +2.0) * +3.0;
+   |                    ^ unexpected `+`
+   |
+help: try removing the `+`
+   |
+LL -     let _ = (1.0 + +2.0) * +3.0;
+LL +     let _ = (1.0 + 2.0) * +3.0;
+   | 
+
+error: leading `+` is not supported
+  --> $DIR/issue-88276-unary-plus.rs:5:28
+   |
+LL |     let _ = (1.0 + +2.0) * +3.0;
+   |                            ^ unexpected `+`
+   |
+help: try removing the `+`
+   |
+LL -     let _ = (1.0 + +2.0) * +3.0;
+LL +     let _ = (1.0 + +2.0) * 3.0;
+   | 
+
+error: leading `+` is not supported
+  --> $DIR/issue-88276-unary-plus.rs:7:14
+   |
+LL |     let _ = [+3, 4+6];
+   |              ^ unexpected `+`
+   |
+help: try removing the `+`
+   |
+LL -     let _ = [+3, 4+6];
+LL +     let _ = [3, 4+6];
+   | 
+
+error: aborting due to 4 previous errors
+