Auto merge of #70024 - Centril:rollup-cppmaxr, r=Centril

Rollup of 8 pull requests

Successful merges:

 - #69528 (Add undo_leak to reset RefCell borrow state)
 - #69589 (ast: `Mac`/`Macro` -> `MacCall`)
 - #69661 (Implement From<&mut str> for String)
 - #69988 (rustc_metadata: Remove `rmeta::MacroDef`)
 - #70006 (resolve: Fix two issues in fresh binding disambiguation)
 - #70011 (def_collector: Fully visit async functions)
 - #70013 (Return feature gate as a `Symbol` )
 - #70018 (Fix "since" field for `Once::is_complete`'s `#[stable]` attribute)

Failed merges:

r? @ghost

Author: bors

src/liballoc/string.rs

@@ -2225,6 +2225,17 @@ impl From<&str> for String {
     }
 }
 
+#[stable(feature = "from_mut_str_for_string", since = "1.44.0")]
+impl From<&mut str> for String {
+    /// Converts a `&mut str` into a `String`.
+    ///
+    /// The result is allocated on the heap.
+    #[inline]
+    fn from(s: &mut str) -> String {
+        s.to_owned()
+    }
+}
+
 #[stable(feature = "from_ref_string", since = "1.35.0")]
 impl From<&String> for String {
     #[inline]

src/libcore/cell.rs

@@ -958,6 +958,33 @@ impl<T: ?Sized> RefCell<T> {
         unsafe { &mut *self.value.get() }
     }
 
+    /// Undo the effect of leaked guards on the borrow state of the `RefCell`.
+    ///
+    /// This call is similar to [`get_mut`] but more specialized. It borrows `RefCell` mutably to
+    /// ensure no borrows exist and then resets the state tracking shared borrows. This is relevant
+    /// if some `Ref` or `RefMut` borrows have been leaked.
+    ///
+    /// [`get_mut`]: #method.get_mut
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(cell_leak)]
+    /// use std::cell::RefCell;
+    ///
+    /// let mut c = RefCell::new(0);
+    /// std::mem::forget(c.borrow_mut());
+    ///
+    /// assert!(c.try_borrow().is_err());
+    /// c.undo_leak();
+    /// assert!(c.try_borrow().is_ok());
+    /// ```
+    #[unstable(feature = "cell_leak", issue = "69099")]
+    pub fn undo_leak(&mut self) -> &mut T {
+        *self.borrow.get_mut() = UNUSED;
+        self.get_mut()
+    }
+
     /// Immutably borrows the wrapped value, returning an error if the value is
     /// currently mutably borrowed.
     ///
@@ -1272,8 +1299,10 @@ impl<'b, T: ?Sized> Ref<'b, T> {
     /// ```
     #[unstable(feature = "cell_leak", issue = "69099")]
     pub fn leak(orig: Ref<'b, T>) -> &'b T {
-        // By forgetting this Ref we ensure that the borrow counter in the RefCell never goes back
-        // to UNUSED again. No further mutable references can be created from the original cell.
+        // By forgetting this Ref we ensure that the borrow counter in the RefCell can't go back to
+        // UNUSED within the lifetime `'b`. Resetting the reference tracking state would require a
+        // unique reference to the borrowed RefCell. No further mutable references can be created
+        // from the original cell.
         mem::forget(orig.borrow);
         orig.value
     }
@@ -1387,9 +1416,11 @@ impl<'b, T: ?Sized> RefMut<'b, T> {
     /// ```
     #[unstable(feature = "cell_leak", issue = "69099")]
     pub fn leak(orig: RefMut<'b, T>) -> &'b mut T {
-        // By forgetting this BorrowRefMut we ensure that the borrow counter in the RefCell never
-        // goes back to UNUSED again. No further references can be created from the original cell,
-        // making the current borrow the only reference for the remaining lifetime.
+        // By forgetting this BorrowRefMut we ensure that the borrow counter in the RefCell can't
+        // go back to UNUSED within the lifetime `'b`. Resetting the reference tracking state would
+        // require a unique reference to the borrowed RefCell. No further references can be created
+        // from the original cell within that lifetime, making the current borrow the only
+        // reference for the remaining lifetime.
         mem::forget(orig.borrow);
         orig.value
     }

src/librustc_ast/ast.rs

@@ -14,7 +14,7 @@
 //! - [`Generics`], [`GenericParam`], [`WhereClause`]: Metadata associated with generic parameters.
 //! - [`EnumDef`] and [`Variant`]: Enum declaration.
 //! - [`Lit`] and [`LitKind`]: Literal expressions.
-//! - [`MacroDef`], [`MacStmtStyle`], [`Mac`], [`MacDelimeter`]: Macro definition and invocation.
+//! - [`MacroDef`], [`MacStmtStyle`], [`MacCall`], [`MacDelimeter`]: Macro definition and invocation.
 //! - [`Attribute`]: Metadata associated with item.
 //! - [`UnOp`], [`UnOpKind`], [`BinOp`], [`BinOpKind`]: Unary and binary operators.
 
@@ -513,7 +513,7 @@ impl Pat {
                 TyKind::Path(None, Path::from_ident(*ident))
             }
             PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
-            PatKind::Mac(mac) => TyKind::Mac(mac.clone()),
+            PatKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
             // `&mut? P` can be reinterpreted as `&mut? T` where `T` is `P` reparsed as a type.
             PatKind::Ref(pat, mutbl) => {
                 pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?
@@ -567,7 +567,7 @@ impl Pat {
             | PatKind::Range(..)
             | PatKind::Ident(..)
             | PatKind::Path(..)
-            | PatKind::Mac(_) => {}
+            | PatKind::MacCall(_) => {}
         }
     }
 
@@ -682,7 +682,7 @@ pub enum PatKind {
     Paren(P<Pat>),
 
     /// A macro pattern; pre-expansion.
-    Mac(Mac),
+    MacCall(MacCall),
 }
 
 #[derive(
@@ -881,9 +881,9 @@ impl Stmt {
     pub fn add_trailing_semicolon(mut self) -> Self {
         self.kind = match self.kind {
             StmtKind::Expr(expr) => StmtKind::Semi(expr),
-            StmtKind::Mac(mac) => {
-                StmtKind::Mac(mac.map(|(mac, _style, attrs)| (mac, MacStmtStyle::Semicolon, attrs)))
-            }
+            StmtKind::MacCall(mac) => StmtKind::MacCall(
+                mac.map(|(mac, _style, attrs)| (mac, MacStmtStyle::Semicolon, attrs)),
+            ),
             kind => kind,
         };
         self
@@ -917,7 +917,7 @@ pub enum StmtKind {
     /// Just a trailing semi-colon.
     Empty,
     /// Macro.
-    Mac(P<(Mac, MacStmtStyle, AttrVec)>),
+    MacCall(P<(MacCall, MacStmtStyle, AttrVec)>),
 }
 
 #[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
@@ -1057,7 +1057,7 @@ impl Expr {
         let kind = match &self.kind {
             // Trivial conversions.
             ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
-            ExprKind::Mac(mac) => TyKind::Mac(mac.clone()),
+            ExprKind::MacCall(mac) => TyKind::MacCall(mac.clone()),
 
             ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
 
@@ -1127,7 +1127,7 @@ impl Expr {
             ExprKind::Continue(..) => ExprPrecedence::Continue,
             ExprKind::Ret(..) => ExprPrecedence::Ret,
             ExprKind::InlineAsm(..) => ExprPrecedence::InlineAsm,
-            ExprKind::Mac(..) => ExprPrecedence::Mac,
+            ExprKind::MacCall(..) => ExprPrecedence::Mac,
             ExprKind::Struct(..) => ExprPrecedence::Struct,
             ExprKind::Repeat(..) => ExprPrecedence::Repeat,
             ExprKind::Paren(..) => ExprPrecedence::Paren,
@@ -1259,7 +1259,7 @@ pub enum ExprKind {
     InlineAsm(P<InlineAsm>),
 
     /// A macro invocation; pre-expansion.
-    Mac(Mac),
+    MacCall(MacCall),
 
     /// A struct literal expression.
     ///
@@ -1345,13 +1345,13 @@ pub enum Movability {
 /// Represents a macro invocation. The `path` indicates which macro
 /// is being invoked, and the `args` are arguments passed to it.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
-pub struct Mac {
+pub struct MacCall {
     pub path: Path,
     pub args: P<MacArgs>,
     pub prior_type_ascription: Option<(Span, bool)>,
 }
 
-impl Mac {
+impl MacCall {
     pub fn span(&self) -> Span {
         self.path.span.to(self.args.span().unwrap_or(self.path.span))
     }
@@ -1446,7 +1446,7 @@ impl MacDelimiter {
 }
 
 /// Represents a macro definition.
-#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub struct MacroDef {
     pub body: P<MacArgs>,
     /// `true` if macro was defined with `macro_rules`.
@@ -1881,7 +1881,7 @@ pub enum TyKind {
     /// Inferred type of a `self` or `&self` argument in a method.
     ImplicitSelf,
     /// A macro in the type position.
-    Mac(Mac),
+    MacCall(MacCall),
     /// Placeholder for a kind that has failed to be defined.
     Err,
     /// Placeholder for a `va_list`.
@@ -2574,7 +2574,7 @@ pub enum ItemKind {
     /// A macro invocation.
     ///
     /// E.g., `foo!(..)`.
-    Mac(Mac),
+    MacCall(MacCall),
 
     /// A macro definition.
     MacroDef(MacroDef),
@@ -2586,7 +2586,7 @@ impl ItemKind {
         match self {
             Use(..) | Static(..) | Const(..) | Fn(..) | Mod(..) | GlobalAsm(..) | TyAlias(..)
             | Struct(..) | Union(..) | Trait(..) | TraitAlias(..) | MacroDef(..) => "a",
-            ExternCrate(..) | ForeignMod(..) | Mac(..) | Enum(..) | Impl { .. } => "an",
+            ExternCrate(..) | ForeignMod(..) | MacCall(..) | Enum(..) | Impl { .. } => "an",
         }
     }
 
@@ -2606,7 +2606,7 @@ impl ItemKind {
             ItemKind::Union(..) => "union",
             ItemKind::Trait(..) => "trait",
             ItemKind::TraitAlias(..) => "trait alias",
-            ItemKind::Mac(..) => "item macro invocation",
+            ItemKind::MacCall(..) => "item macro invocation",
             ItemKind::MacroDef(..) => "macro definition",
             ItemKind::Impl { .. } => "implementation",
         }
@@ -2648,14 +2648,14 @@ pub enum AssocItemKind {
     /// An associated type.
     TyAlias(Defaultness, Generics, GenericBounds, Option<P<Ty>>),
     /// A macro expanding to associated items.
-    Macro(Mac),
+    MacCall(MacCall),
 }
 
 impl AssocItemKind {
     pub fn defaultness(&self) -> Defaultness {
         match *self {
             Self::Const(def, ..) | Self::Fn(def, ..) | Self::TyAlias(def, ..) => def,
-            Self::Macro(..) => Defaultness::Final,
+            Self::MacCall(..) => Defaultness::Final,
         }
     }
 }
@@ -2666,7 +2666,7 @@ impl From<AssocItemKind> for ItemKind {
             AssocItemKind::Const(a, b, c) => ItemKind::Const(a, b, c),
             AssocItemKind::Fn(a, b, c, d) => ItemKind::Fn(a, b, c, d),
             AssocItemKind::TyAlias(a, b, c, d) => ItemKind::TyAlias(a, b, c, d),
-            AssocItemKind::Macro(a) => ItemKind::Mac(a),
+            AssocItemKind::MacCall(a) => ItemKind::MacCall(a),
         }
     }
 }
@@ -2679,7 +2679,7 @@ impl TryFrom<ItemKind> for AssocItemKind {
             ItemKind::Const(a, b, c) => AssocItemKind::Const(a, b, c),
             ItemKind::Fn(a, b, c, d) => AssocItemKind::Fn(a, b, c, d),
             ItemKind::TyAlias(a, b, c, d) => AssocItemKind::TyAlias(a, b, c, d),
-            ItemKind::Mac(a) => AssocItemKind::Macro(a),
+            ItemKind::MacCall(a) => AssocItemKind::MacCall(a),
             _ => return Err(item_kind),
         })
     }
@@ -2695,7 +2695,7 @@ pub enum ForeignItemKind {
     /// A foreign type.
     TyAlias(Defaultness, Generics, GenericBounds, Option<P<Ty>>),
     /// A macro expanding to foreign items.
-    Macro(Mac),
+    MacCall(MacCall),
 }
 
 impl From<ForeignItemKind> for ItemKind {
@@ -2704,7 +2704,7 @@ impl From<ForeignItemKind> for ItemKind {
             ForeignItemKind::Static(a, b, c) => ItemKind::Static(a, b, c),
             ForeignItemKind::Fn(a, b, c, d) => ItemKind::Fn(a, b, c, d),
             ForeignItemKind::TyAlias(a, b, c, d) => ItemKind::TyAlias(a, b, c, d),
-            ForeignItemKind::Macro(a) => ItemKind::Mac(a),
+            ForeignItemKind::MacCall(a) => ItemKind::MacCall(a),
         }
     }
 }
@@ -2717,7 +2717,7 @@ impl TryFrom<ItemKind> for ForeignItemKind {
             ItemKind::Static(a, b, c) => ForeignItemKind::Static(a, b, c),
             ItemKind::Fn(a, b, c, d) => ForeignItemKind::Fn(a, b, c, d),
             ItemKind::TyAlias(a, b, c, d) => ForeignItemKind::TyAlias(a, b, c, d),
-            ItemKind::Mac(a) => ForeignItemKind::Macro(a),
+            ItemKind::MacCall(a) => ForeignItemKind::MacCall(a),
             _ => return Err(item_kind),
         })
     }

src/librustc_ast/attr/mod.rs

@@ -679,7 +679,7 @@ impl HasAttrs for StmtKind {
             StmtKind::Local(ref local) => local.attrs(),
             StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => expr.attrs(),
             StmtKind::Empty | StmtKind::Item(..) => &[],
-            StmtKind::Mac(ref mac) => {
+            StmtKind::MacCall(ref mac) => {
                 let (_, _, ref attrs) = **mac;
                 attrs.attrs()
             }
@@ -691,7 +691,7 @@ impl HasAttrs for StmtKind {
             StmtKind::Local(local) => local.visit_attrs(f),
             StmtKind::Expr(expr) | StmtKind::Semi(expr) => expr.visit_attrs(f),
             StmtKind::Empty | StmtKind::Item(..) => {}
-            StmtKind::Mac(mac) => {
+            StmtKind::MacCall(mac) => {
                 let (_mac, _style, attrs) = mac.deref_mut();
                 attrs.visit_attrs(f);
             }

src/librustc_ast/mut_visit.rs

@@ -202,7 +202,7 @@ pub trait MutVisitor: Sized {
         noop_visit_local(l, self);
     }
 
-    fn visit_mac(&mut self, _mac: &mut Mac) {
+    fn visit_mac(&mut self, _mac: &mut MacCall) {
         panic!("visit_mac disabled by default");
         // N.B., see note about macros above. If you really want a visitor that
         // works on macros, use this definition in your trait impl:
@@ -482,7 +482,7 @@ pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
             vis.visit_id(id);
             visit_vec(bounds, |bound| vis.visit_param_bound(bound));
         }
-        TyKind::Mac(mac) => vis.visit_mac(mac),
+        TyKind::MacCall(mac) => vis.visit_mac(mac),
     }
     vis.visit_span(span);
 }
@@ -584,8 +584,8 @@ pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
     vis.visit_span(span);
 }
 
-pub fn noop_visit_mac<T: MutVisitor>(mac: &mut Mac, vis: &mut T) {
-    let Mac { path, args, prior_type_ascription: _ } = mac;
+pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
+    let MacCall { path, args, prior_type_ascription: _ } = mac;
     vis.visit_path(path);
     visit_mac_args(args, vis);
 }
@@ -926,7 +926,7 @@ pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
             vis.visit_generics(generics);
             visit_bounds(bounds, vis);
         }
-        ItemKind::Mac(m) => vis.visit_mac(m),
+        ItemKind::MacCall(m) => vis.visit_mac(m),
         ItemKind::MacroDef(def) => vis.visit_macro_def(def),
     }
 }
@@ -955,7 +955,7 @@ pub fn noop_flat_map_assoc_item<T: MutVisitor>(
             visit_bounds(bounds, visitor);
             visit_opt(ty, |ty| visitor.visit_ty(ty));
         }
-        AssocItemKind::Macro(mac) => visitor.visit_mac(mac),
+        AssocItemKind::MacCall(mac) => visitor.visit_mac(mac),
     }
     visitor.visit_span(span);
     smallvec![item]
@@ -1043,7 +1043,7 @@ pub fn noop_flat_map_foreign_item<T: MutVisitor>(
             visit_bounds(bounds, visitor);
             visit_opt(ty, |ty| visitor.visit_ty(ty));
         }
-        ForeignItemKind::Macro(mac) => visitor.visit_mac(mac),
+        ForeignItemKind::MacCall(mac) => visitor.visit_mac(mac),
     }
     visitor.visit_span(span);
     smallvec![item]
@@ -1082,7 +1082,7 @@ pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
             visit_vec(elems, |elem| vis.visit_pat(elem))
         }
         PatKind::Paren(inner) => vis.visit_pat(inner),
-        PatKind::Mac(mac) => vis.visit_mac(mac),
+        PatKind::MacCall(mac) => vis.visit_mac(mac),
     }
     vis.visit_span(span);
 }
@@ -1219,7 +1219,7 @@ pub fn noop_visit_expr<T: MutVisitor>(Expr { kind, id, span, attrs }: &mut Expr,
             }
             visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
         }
-        ExprKind::Mac(mac) => vis.visit_mac(mac),
+        ExprKind::MacCall(mac) => vis.visit_mac(mac),
         ExprKind::Struct(path, fields, expr) => {
             vis.visit_path(path);
             fields.flat_map_in_place(|field| vis.flat_map_field(field));
@@ -1275,11 +1275,11 @@ pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
         StmtKind::Expr(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect(),
         StmtKind::Semi(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect(),
         StmtKind::Empty => smallvec![StmtKind::Empty],
-        StmtKind::Mac(mut mac) => {
+        StmtKind::MacCall(mut mac) => {
             let (mac_, _semi, attrs) = mac.deref_mut();
             vis.visit_mac(mac_);
             visit_thin_attrs(attrs, vis);
-            smallvec![StmtKind::Mac(mac)]
+            smallvec![StmtKind::MacCall(mac)]
         }
     }
 }