Auto merge of rust-lang#105166 - matthiaskrgr:rollup-s9l6vt2, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - rust-lang#104614 (Add `type_ascribe!` macro as placeholder syntax for type ascription)
 - rust-lang#105126 (Make `VecDeque::new_in` unstably const)
 - rust-lang#105132 (Migrate summary toggle filter to CSS variable)
 - rust-lang#105136 (clarify comment on Deref promotion)
 - rust-lang#105137 (Add tracking issue number for `file_create_new` feature)
 - rust-lang#105143 (rustdoc: use simpler CSS for setting the font on scraped examples)

Failed merges:

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

Author: bors

compiler/rustc_builtin_macros/src/lib.rs

@@ -45,6 +45,7 @@ mod log_syntax;
 mod source_util;
 mod test;
 mod trace_macros;
+mod type_ascribe;
 mod util;
 
 pub mod asm;
@@ -92,6 +93,7 @@ pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
         unreachable: edition_panic::expand_unreachable,
         stringify: source_util::expand_stringify,
         trace_macros: trace_macros::expand_trace_macros,
+        type_ascribe: type_ascribe::expand_type_ascribe,
     }
 
     register_attr! {

compiler/rustc_builtin_macros/src/type_ascribe.rs

@@ -0,0 +1,35 @@
+use rustc_ast::ptr::P;
+use rustc_ast::tokenstream::TokenStream;
+use rustc_ast::{token, Expr, ExprKind, Ty};
+use rustc_errors::PResult;
+use rustc_expand::base::{self, DummyResult, ExtCtxt, MacEager};
+use rustc_span::Span;
+
+pub fn expand_type_ascribe(
+    cx: &mut ExtCtxt<'_>,
+    span: Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'static> {
+    let (expr, ty) = match parse_ascribe(cx, tts) {
+        Ok(parsed) => parsed,
+        Err(mut err) => {
+            err.emit();
+            return DummyResult::any(span);
+        }
+    };
+
+    let asc_expr = cx.expr(span, ExprKind::Type(expr, ty));
+
+    return MacEager::expr(asc_expr);
+}
+
+fn parse_ascribe<'a>(cx: &mut ExtCtxt<'a>, stream: TokenStream) -> PResult<'a, (P<Expr>, P<Ty>)> {
+    let mut parser = cx.new_parser_from_tts(stream);
+
+    let expr = parser.parse_expr()?;
+    parser.expect(&token::Comma)?;
+
+    let ty = parser.parse_ty()?;
+
+    Ok((expr, ty))
+}

compiler/rustc_const_eval/src/transform/promote_consts.rs

@@ -318,14 +318,14 @@ impl<'tcx> Validator<'_, 'tcx> {
                 match elem {
                     ProjectionElem::Deref => {
                         let mut promotable = false;
+                        // When a static is used by-value, that gets desugared to `*STATIC_ADDR`,
+                        // and we need to be able to promote this. So check if this deref matches
+                        // that specific pattern.
+
                         // We need to make sure this is a `Deref` of a local with no further projections.
                         // Discussion can be found at
                         // https://github.com/rust-lang/rust/pull/74945#discussion_r463063247
                         if let Some(local) = place_base.as_local() {
-                            // This is a special treatment for cases like *&STATIC where STATIC is a
-                            // global static variable.
-                            // This pattern is generated only when global static variables are directly
-                            // accessed and is qualified for promotion safely.
                             if let TempState::Defined { location, .. } = self.temps[local] {
                                 let def_stmt = self.body[location.block]
                                     .statements

compiler/rustc_span/src/symbol.rs

@@ -1488,6 +1488,7 @@ symbols! {
         ty,
         type_alias_enum_variants,
         type_alias_impl_trait,
+        type_ascribe,
         type_ascription,
         type_changing_struct_update,
         type_id,

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

@@ -566,10 +566,9 @@ impl<T, A: Allocator> VecDeque<T, A> {
     ///
     /// let deque: VecDeque<u32> = VecDeque::new();
     /// ```
-    // FIXME: This should probably be const
     #[inline]
     #[unstable(feature = "allocator_api", issue = "32838")]
-    pub fn new_in(alloc: A) -> VecDeque<T, A> {
+    pub const fn new_in(alloc: A) -> VecDeque<T, A> {
         VecDeque { head: 0, len: 0, buf: RawVec::new_in(alloc) }
     }
 
@@ -2152,7 +2151,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
 
             self.head = tail;
         } else {
-            // ´free` is smaller than both `head_len` and `tail_len`.
+            // `free` is smaller than both `head_len` and `tail_len`.
             // the general algorithm for this first moves the slices
             // right next to each other and then uses `slice::rotate`
             // to rotate them into place:

library/core/src/macros/mod.rs

@@ -1546,6 +1546,18 @@ pub(crate) mod builtin {
         /* compiler built-in */
     }
 
+    /// Unstable placeholder for type ascription.
+    #[rustc_builtin_macro]
+    #[unstable(
+        feature = "type_ascription",
+        issue = "23416",
+        reason = "placeholder syntax for type ascription"
+    )]
+    #[cfg(not(bootstrap))]
+    pub macro type_ascribe($expr:expr, $ty:ty) {
+        /* compiler built-in */
+    }
+
     /// Unstable implementation detail of the `rustc` compiler, do not use.
     #[rustc_builtin_macro]
     #[stable(feature = "rust1", since = "1.0.0")]

library/core/src/prelude/v1.rs

@@ -98,3 +98,11 @@ pub use crate::macros::builtin::cfg_accessible;
     reason = "`cfg_eval` is a recently implemented feature"
 )]
 pub use crate::macros::builtin::cfg_eval;
+
+#[unstable(
+    feature = "type_ascription",
+    issue = "23416",
+    reason = "placeholder syntax for type ascription"
+)]
+#[cfg(not(bootstrap))]
+pub use crate::macros::builtin::type_ascribe;

library/std/src/fs.rs

@@ -401,7 +401,7 @@ impl File {
     ///     Ok(())
     /// }
     /// ```
-    #[unstable(feature = "file_create_new", issue = "none")]
+    #[unstable(feature = "file_create_new", issue = "105135")]
     pub fn create_new<P: AsRef<Path>>(path: P) -> io::Result<File> {
         OpenOptions::new().read(true).write(true).create_new(true).open(path.as_ref())
     }

library/std/src/prelude/v1.rs

@@ -85,6 +85,15 @@ pub use core::prelude::v1::cfg_accessible;
 )]
 pub use core::prelude::v1::cfg_eval;
 
+// Do not `doc(no_inline)` either.
+#[unstable(
+    feature = "type_ascription",
+    issue = "23416",
+    reason = "placeholder syntax for type ascription"
+)]
+#[cfg(not(bootstrap))]
+pub use core::prelude::v1::type_ascribe;
+
 // The file so far is equivalent to src/libcore/prelude/v1.rs,
 // and below to src/liballoc/prelude.rs.
 // Those files are duplicated rather than using glob imports

src/librustdoc/html/static/css/rustdoc.css

@@ -197,9 +197,7 @@ a.srclink,
 #help-button > a,
 details.rustdoc-toggle.top-doc > summary,
 details.rustdoc-toggle.non-exhaustive > summary,
-.scraped-example-title,
-.more-examples-toggle summary, .more-examples-toggle .hide-more,
-.example-links a,
+.scraped-example-list,
 /* This selector is for the items listed in the "all items" page. */
 ul.all-items {
 	font-family: "Fira Sans", Arial, NanumBarunGothic, sans-serif;
@@ -1516,6 +1514,7 @@ details.rustdoc-toggle > summary::before {
 	display: inline-block;
 	vertical-align: middle;
 	opacity: .5;
+	filter: var(--toggle-filter);
 }
 
 details.rustdoc-toggle > summary.hideme > span,