Auto merge of #97356 - Dylan-DPC:rollup-bhceawj, r=Dylan-DPC

Rollup of 4 pull requests

Successful merges:

 - #97288 (Lifetime variance fixes for rustdoc)
 - #97298 (Parse expression after `else` as a condition if followed by `{`)
 - #97308 (Stabilize `cell_filter_map`)
 - #97321 (explain how to turn integers into fn ptrs)

Failed merges:

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

compiler/rustc_hir/src/hir.rs

@@ -343,12 +343,12 @@ pub struct GenericArgs<'hir> {
     pub span_ext: Span,
 }
 
-impl GenericArgs<'_> {
+impl<'hir> GenericArgs<'hir> {
     pub const fn none() -> Self {
         Self { args: &[], bindings: &[], parenthesized: false, span_ext: DUMMY_SP }
     }
 
-    pub fn inputs(&self) -> &[Ty<'_>] {
+    pub fn inputs(&self) -> &[Ty<'hir>] {
         if self.parenthesized {
             for arg in self.args {
                 match arg {
@@ -549,7 +549,7 @@ impl<'hir> Generics<'hir> {
         &NOPE
     }
 
-    pub fn get_named(&self, name: Symbol) -> Option<&GenericParam<'_>> {
+    pub fn get_named(&self, name: Symbol) -> Option<&GenericParam<'hir>> {
         for param in self.params {
             if name == param.name.ident().name {
                 return Some(param);
@@ -608,7 +608,7 @@ impl<'hir> Generics<'hir> {
     pub fn bounds_for_param(
         &self,
         param_def_id: LocalDefId,
-    ) -> impl Iterator<Item = &WhereBoundPredicate<'_>> {
+    ) -> impl Iterator<Item = &WhereBoundPredicate<'hir>> {
         self.predicates.iter().filter_map(move |pred| match pred {
             WherePredicate::BoundPredicate(bp) if bp.is_param_bound(param_def_id.to_def_id()) => {
                 Some(bp)

compiler/rustc_parse/src/parser/expr.rs

@@ -2010,6 +2010,12 @@ impl<'a> Parser<'a> {
         Ok(self.mk_expr(blk.span, ExprKind::Block(blk, opt_label), attrs))
     }
 
+    /// Parse a block which takes no attributes and has no label
+    fn parse_simple_block(&mut self) -> PResult<'a, P<Expr>> {
+        let blk = self.parse_block()?;
+        Ok(self.mk_expr(blk.span, ExprKind::Block(blk, None), AttrVec::new()))
+    }
+
     /// Recover on an explicitly quantified closure expression, e.g., `for<'a> |x: &'a u8| *x + 1`.
     fn recover_quantified_closure_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
         let lo = self.token.span;
@@ -2157,6 +2163,15 @@ impl<'a> Parser<'a> {
         let lo = self.prev_token.span;
         let cond = self.parse_cond_expr()?;
 
+        self.parse_if_after_cond(attrs, lo, cond)
+    }
+
+    fn parse_if_after_cond(
+        &mut self,
+        attrs: AttrVec,
+        lo: Span,
+        cond: P<Expr>,
+    ) -> PResult<'a, P<Expr>> {
         let missing_then_block_binop_span = || {
             match cond.kind {
                 ExprKind::Binary(Spanned { span: binop_span, .. }, _, ref right)
@@ -2164,7 +2179,6 @@ impl<'a> Parser<'a> {
                 _ => None
             }
         };
-
         // Verify that the parsed `if` condition makes sense as a condition. If it is a block, then
         // verify that the last statement is either an implicit return (no `;`) or an explicit
         // return. This won't catch blocks with an explicit `return`, but that would be caught by
@@ -2256,15 +2270,53 @@ impl<'a> Parser<'a> {
 
     /// Parses an `else { ... }` expression (`else` token already eaten).
     fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> {
-        let ctx_span = self.prev_token.span; // `else`
+        let else_span = self.prev_token.span; // `else`
         let attrs = self.parse_outer_attributes()?.take_for_recovery(); // For recovery.
         let expr = if self.eat_keyword(kw::If) {
             self.parse_if_expr(AttrVec::new())?
+        } else if self.check(&TokenKind::OpenDelim(Delimiter::Brace)) {
+            self.parse_simple_block()?
         } else {
-            let blk = self.parse_block()?;
-            self.mk_expr(blk.span, ExprKind::Block(blk, None), AttrVec::new())
+            let snapshot = self.create_snapshot_for_diagnostic();
+            let first_tok = super::token_descr(&self.token);
+            let first_tok_span = self.token.span;
+            match self.parse_expr() {
+                Ok(cond)
+                // If it's not a free-standing expression, and is followed by a block,
+                // then it's very likely the condition to an `else if`.
+                    if self.check(&TokenKind::OpenDelim(Delimiter::Brace))
+                        && classify::expr_requires_semi_to_be_stmt(&cond) =>
+                {
+                    self.struct_span_err(first_tok_span, format!("expected `{{`, found {first_tok}"))
+                        .span_label(else_span, "expected an `if` or a block after this `else`")
+                        .span_suggestion(
+                            cond.span.shrink_to_lo(),
+                            "add an `if` if this is the condition to an chained `if` statement after the `else`",
+                            "if ".to_string(),
+                            Applicability::MaybeIncorrect,
+                        ).multipart_suggestion(
+                            "... otherwise, place this expression inside of a block if it is not an `if` condition",
+                            vec![
+                                (cond.span.shrink_to_lo(), "{ ".to_string()),
+                                (cond.span.shrink_to_hi(), " }".to_string()),
+                            ],
+                            Applicability::MaybeIncorrect,
+                        )
+                        .emit();
+                    self.parse_if_after_cond(AttrVec::new(), cond.span.shrink_to_lo(), cond)?
+                }
+                Err(e) => {
+                    e.cancel();
+                    self.restore_snapshot(snapshot);
+                    self.parse_simple_block()?
+                },
+                Ok(_) => {
+                    self.restore_snapshot(snapshot);
+                    self.parse_simple_block()?
+                },
+            }
         };
-        self.error_on_if_block_attrs(ctx_span, true, expr.span, &attrs);
+        self.error_on_if_block_attrs(else_span, true, expr.span, &attrs);
         Ok(expr)
     }
 

library/core/src/cell.rs

@@ -1390,8 +1390,6 @@ impl<'b, T: ?Sized> Ref<'b, T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(cell_filter_map)]
-    ///
     /// use std::cell::{RefCell, Ref};
     ///
     /// let c = RefCell::new(vec![1, 2, 3]);
@@ -1399,7 +1397,7 @@ impl<'b, T: ?Sized> Ref<'b, T> {
     /// let b2: Result<Ref<u32>, _> = Ref::filter_map(b1, |v| v.get(1));
     /// assert_eq!(*b2.unwrap(), 2);
     /// ```
-    #[unstable(feature = "cell_filter_map", reason = "recently added", issue = "81061")]
+    #[stable(feature = "cell_filter_map", since = "1.63.0")]
     #[inline]
     pub fn filter_map<U: ?Sized, F>(orig: Ref<'b, T>, f: F) -> Result<Ref<'b, U>, Self>
     where
@@ -1538,8 +1536,6 @@ impl<'b, T: ?Sized> RefMut<'b, T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(cell_filter_map)]
-    ///
     /// use std::cell::{RefCell, RefMut};
     ///
     /// let c = RefCell::new(vec![1, 2, 3]);
@@ -1555,7 +1551,7 @@ impl<'b, T: ?Sized> RefMut<'b, T> {
     ///
     /// assert_eq!(*c.borrow(), vec![1, 4, 3]);
     /// ```
-    #[unstable(feature = "cell_filter_map", reason = "recently added", issue = "81061")]
+    #[stable(feature = "cell_filter_map", since = "1.63.0")]
     #[inline]
     pub fn filter_map<U: ?Sized, F>(mut orig: RefMut<'b, T>, f: F) -> Result<RefMut<'b, U>, Self>
     where

library/core/src/intrinsics.rs

@@ -930,6 +930,9 @@ extern "rust-intrinsic" {
     /// fn foo() -> i32 {
     ///     0
     /// }
+    /// // Crucially, we `as`-cast to a raw pointer before `transmute`ing to a function pointer.
+    /// // This avoids an integer-to-pointer `transmute`, which can be problematic.
+    /// // Transmuting between raw pointers and function pointers (i.e., two pointer types) is fine.
     /// let pointer = foo as *const ();
     /// let function = unsafe {
     ///     std::mem::transmute::<*const (), fn() -> i32>(pointer)

library/core/src/primitive_docs.rs

@@ -1351,6 +1351,32 @@ mod prim_ref {}
 /// is a reference to the function-specific ZST. `&bar` is basically never what you
 /// want when `bar` is a function.
 ///
+/// ### Casting to and from integers
+///
+/// You cast function pointers directly to integers:
+///
+/// ```rust
+/// let fnptr: fn(i32) -> i32 = |x| x+2;
+/// let fnptr_addr = fnptr as usize;
+/// ```
+///
+/// However, a direct cast back is not possible. You need to use `transmute`:
+///
+/// ```rust
+/// # let fnptr: fn(i32) -> i32 = |x| x+2;
+/// # let fnptr_addr = fnptr as usize;
+/// let fnptr = fnptr_addr as *const ();
+/// let fnptr: fn(i32) -> i32 = unsafe { std::mem::transmute(fnptr) };
+/// assert_eq!(fnptr(40), 42);
+/// ```
+///
+/// Crucially, we `as`-cast to a raw pointer before `transmute`ing to a function pointer.
+/// This avoids an integer-to-pointer `transmute`, which can be problematic.
+/// Transmuting between raw pointers and function pointers (i.e., two pointer types) is fine.
+///
+/// Note that all of this is not portable to platforms where function pointers and data pointers
+/// have different sizes.
+///
 /// ### Traits
 ///
 /// Function pointers implement the following traits:

library/std/src/primitive_docs.rs

@@ -1351,6 +1351,32 @@ mod prim_ref {}
 /// is a reference to the function-specific ZST. `&bar` is basically never what you
 /// want when `bar` is a function.
 ///
+/// ### Casting to and from integers
+///
+/// You cast function pointers directly to integers:
+///
+/// ```rust
+/// let fnptr: fn(i32) -> i32 = |x| x+2;
+/// let fnptr_addr = fnptr as usize;
+/// ```
+///
+/// However, a direct cast back is not possible. You need to use `transmute`:
+///
+/// ```rust
+/// # let fnptr: fn(i32) -> i32 = |x| x+2;
+/// # let fnptr_addr = fnptr as usize;
+/// let fnptr = fnptr_addr as *const ();
+/// let fnptr: fn(i32) -> i32 = unsafe { std::mem::transmute(fnptr) };
+/// assert_eq!(fnptr(40), 42);
+/// ```
+///
+/// Crucially, we `as`-cast to a raw pointer before `transmute`ing to a function pointer.
+/// This avoids an integer-to-pointer `transmute`, which can be problematic.
+/// Transmuting between raw pointers and function pointers (i.e., two pointer types) is fine.
+///
+/// Note that all of this is not portable to platforms where function pointers and data pointers
+/// have different sizes.
+///
 /// ### Traits
 ///
 /// Function pointers implement the following traits:

src/librustdoc/clean/inline.rs

@@ -218,7 +218,7 @@ pub(crate) fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean
     }
 }
 
-fn build_external_function(cx: &mut DocContext<'_>, did: DefId) -> clean::Function {
+fn build_external_function<'tcx>(cx: &mut DocContext<'tcx>, did: DefId) -> clean::Function {
     let sig = cx.tcx.fn_sig(did);
 
     let predicates = cx.tcx.predicates_of(did);

src/librustdoc/clean/mod.rs

@@ -44,12 +44,12 @@ use utils::*;
 pub(crate) use self::types::*;
 pub(crate) use self::utils::{get_auto_trait_and_blanket_impls, krate, register_res};
 
-pub(crate) trait Clean<T> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> T;
+pub(crate) trait Clean<'tcx, T> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> T;
 }
 
-impl Clean<Item> for DocModule<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Item {
+impl<'tcx> Clean<'tcx, Item> for DocModule<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Item {
         let mut items: Vec<Item> = vec![];
         items.extend(
             self.foreigns
@@ -89,14 +89,14 @@ impl Clean<Item> for DocModule<'_> {
     }
 }
 
-impl Clean<Attributes> for [ast::Attribute] {
+impl<'tcx> Clean<'tcx, Attributes> for [ast::Attribute] {
     fn clean(&self, _cx: &mut DocContext<'_>) -> Attributes {
         Attributes::from_ast(self, None)
     }
 }
 
-impl Clean<Option<GenericBound>> for hir::GenericBound<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Option<GenericBound> {
+impl<'tcx> Clean<'tcx, Option<GenericBound>> for hir::GenericBound<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Option<GenericBound> {
         Some(match *self {
             hir::GenericBound::Outlives(lt) => GenericBound::Outlives(lt.clean(cx)),
             hir::GenericBound::LangItemTrait(lang_item, span, _, generic_args) => {
@@ -131,9 +131,9 @@ impl Clean<Option<GenericBound>> for hir::GenericBound<'_> {
     }
 }
 
-fn clean_trait_ref_with_bindings(
-    cx: &mut DocContext<'_>,
-    trait_ref: ty::TraitRef<'_>,
+fn clean_trait_ref_with_bindings<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    trait_ref: ty::TraitRef<'tcx>,
     bindings: &[TypeBinding],
 ) -> Path {
     let kind = cx.tcx.def_kind(trait_ref.def_id).into();
@@ -148,15 +148,15 @@ fn clean_trait_ref_with_bindings(
     path
 }
 
-impl Clean<Path> for ty::TraitRef<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Path {
+impl<'tcx> Clean<'tcx, Path> for ty::TraitRef<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Path {
         clean_trait_ref_with_bindings(cx, *self, &[])
     }
 }
 
-fn clean_poly_trait_ref_with_bindings(
-    cx: &mut DocContext<'_>,
-    poly_trait_ref: ty::PolyTraitRef<'_>,
+fn clean_poly_trait_ref_with_bindings<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    poly_trait_ref: ty::PolyTraitRef<'tcx>,
     bindings: &[TypeBinding],
 ) -> GenericBound {
     let poly_trait_ref = poly_trait_ref.lift_to_tcx(cx.tcx).unwrap();
@@ -182,14 +182,14 @@ fn clean_poly_trait_ref_with_bindings(
     )
 }
 
-impl<'tcx> Clean<GenericBound> for ty::PolyTraitRef<'tcx> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> GenericBound {
+impl<'tcx> Clean<'tcx, GenericBound> for ty::PolyTraitRef<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> GenericBound {
         clean_poly_trait_ref_with_bindings(cx, *self, &[])
     }
 }
 
-impl Clean<Lifetime> for hir::Lifetime {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Lifetime {
+impl<'tcx> Clean<'tcx, Lifetime> for hir::Lifetime {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Lifetime {
         let def = cx.tcx.named_region(self.hir_id);
         if let Some(
             rl::Region::EarlyBound(_, node_id)
@@ -205,8 +205,8 @@ impl Clean<Lifetime> for hir::Lifetime {
     }
 }
 
-impl Clean<Constant> for hir::ConstArg {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Constant {
+impl<'tcx> Clean<'tcx, Constant> for hir::ConstArg {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Constant {
         Constant {
             type_: cx
                 .tcx
@@ -217,7 +217,7 @@ impl Clean<Constant> for hir::ConstArg {
     }
 }
 
-impl Clean<Option<Lifetime>> for ty::Region<'_> {
+impl<'tcx> Clean<'tcx, Option<Lifetime>> for ty::Region<'tcx> {
     fn clean(&self, _cx: &mut DocContext<'_>) -> Option<Lifetime> {
         match **self {
             ty::ReStatic => Some(Lifetime::statik()),
@@ -239,8 +239,8 @@ impl Clean<Option<Lifetime>> for ty::Region<'_> {
     }
 }
 
-impl Clean<Option<WherePredicate>> for hir::WherePredicate<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
+impl<'tcx> Clean<'tcx, Option<WherePredicate>> for hir::WherePredicate<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Option<WherePredicate> {
         if !self.in_where_clause() {
             return None;
         }
@@ -279,8 +279,8 @@ impl Clean<Option<WherePredicate>> for hir::WherePredicate<'_> {
     }
 }
 
-impl<'a> Clean<Option<WherePredicate>> for ty::Predicate<'a> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
+impl<'tcx> Clean<'tcx, Option<WherePredicate>> for ty::Predicate<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Option<WherePredicate> {
         let bound_predicate = self.kind();
         match bound_predicate.skip_binder() {
             ty::PredicateKind::Trait(pred) => bound_predicate.rebind(pred).clean(cx),
@@ -300,8 +300,8 @@ impl<'a> Clean<Option<WherePredicate>> for ty::Predicate<'a> {
     }
 }
 
-impl<'a> Clean<Option<WherePredicate>> for ty::PolyTraitPredicate<'a> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
+impl<'tcx> Clean<'tcx, Option<WherePredicate>> for ty::PolyTraitPredicate<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Option<WherePredicate> {
         // `T: ~const Destruct` is hidden because `T: Destruct` is a no-op.
         if self.skip_binder().constness == ty::BoundConstness::ConstIfConst
             && Some(self.skip_binder().def_id()) == cx.tcx.lang_items().destruct_trait()
@@ -318,10 +318,10 @@ impl<'a> Clean<Option<WherePredicate>> for ty::PolyTraitPredicate<'a> {
     }
 }
 
-impl<'tcx> Clean<Option<WherePredicate>>
+impl<'tcx> Clean<'tcx, Option<WherePredicate>>
     for ty::OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>
 {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Option<WherePredicate> {
         let ty::OutlivesPredicate(a, b) = self;
 
         if a.is_empty() && b.is_empty() {
@@ -335,8 +335,10 @@ impl<'tcx> Clean<Option<WherePredicate>>
     }
 }
 
-impl<'tcx> Clean<Option<WherePredicate>> for ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
+impl<'tcx> Clean<'tcx, Option<WherePredicate>>
+    for ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>
+{
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Option<WherePredicate> {
         let ty::OutlivesPredicate(ty, lt) = self;
 
         if lt.is_empty() {
@@ -351,8 +353,8 @@ impl<'tcx> Clean<Option<WherePredicate>> for ty::OutlivesPredicate<Ty<'tcx>, ty:
     }
 }
 
-impl<'tcx> Clean<Term> for ty::Term<'tcx> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Term {
+impl<'tcx> Clean<'tcx, Term> for ty::Term<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Term {
         match self {
             ty::Term::Ty(ty) => Term::Type(ty.clean(cx)),
             ty::Term::Const(c) => Term::Constant(c.clean(cx)),
@@ -360,8 +362,8 @@ impl<'tcx> Clean<Term> for ty::Term<'tcx> {
     }
 }
 
-impl<'tcx> Clean<Term> for hir::Term<'tcx> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Term {
+impl<'tcx> Clean<'tcx, Term> for hir::Term<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Term {
         match self {
             hir::Term::Ty(ty) => Term::Type(ty.clean(cx)),
             hir::Term::Const(c) => {
@@ -372,8 +374,8 @@ impl<'tcx> Clean<Term> for hir::Term<'tcx> {
     }
 }
 
-impl<'tcx> Clean<WherePredicate> for ty::ProjectionPredicate<'tcx> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> WherePredicate {
+impl<'tcx> Clean<'tcx, WherePredicate> for ty::ProjectionPredicate<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> WherePredicate {
         let ty::ProjectionPredicate { projection_ty, term } = self;
         WherePredicate::EqPredicate { lhs: projection_ty.clean(cx), rhs: term.clean(cx) }
     }
@@ -381,7 +383,7 @@ impl<'tcx> Clean<WherePredicate> for ty::ProjectionPredicate<'tcx> {
 
 fn clean_projection<'tcx>(
     ty: ty::ProjectionTy<'tcx>,
-    cx: &mut DocContext<'_>,
+    cx: &mut DocContext<'tcx>,
     def_id: Option<DefId>,
 ) -> Type {
     let lifted = ty.lift_to_tcx(cx.tcx).unwrap();
@@ -401,8 +403,8 @@ fn clean_projection<'tcx>(
     }
 }
 
-impl<'tcx> Clean<Type> for ty::ProjectionTy<'tcx> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Type {
+impl<'tcx> Clean<'tcx, Type> for ty::ProjectionTy<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Type {
         clean_projection(*self, cx, None)
     }
 }
@@ -414,7 +416,10 @@ fn compute_should_show_cast(self_def_id: Option<DefId>, trait_: &Path, self_type
             .map_or(!self_type.is_self_type(), |(id, trait_)| id != trait_)
 }
 
-fn projection_to_path_segment(ty: ty::ProjectionTy<'_>, cx: &mut DocContext<'_>) -> PathSegment {
+fn projection_to_path_segment<'tcx>(
+    ty: ty::ProjectionTy<'tcx>,
+    cx: &mut DocContext<'tcx>,
+) -> PathSegment {
     let item = cx.tcx.associated_item(ty.item_def_id);
     let generics = cx.tcx.generics_of(ty.item_def_id);
     PathSegment {
@@ -426,8 +431,8 @@ fn projection_to_path_segment(ty: ty::ProjectionTy<'_>, cx: &mut DocContext<'_>)
     }
 }
 
-impl Clean<GenericParamDef> for ty::GenericParamDef {
-    fn clean(&self, cx: &mut DocContext<'_>) -> GenericParamDef {
+impl<'tcx> Clean<'tcx, GenericParamDef> for ty::GenericParamDef {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> GenericParamDef {
         let (name, kind) = match self.kind {
             ty::GenericParamDefKind::Lifetime => {
                 (self.name, GenericParamDefKind::Lifetime { outlives: vec![] })
@@ -465,10 +470,10 @@ impl Clean<GenericParamDef> for ty::GenericParamDef {
     }
 }
 
-fn clean_generic_param(
-    cx: &mut DocContext<'_>,
-    generics: Option<&hir::Generics<'_>>,
-    param: &hir::GenericParam<'_>,
+fn clean_generic_param<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    generics: Option<&hir::Generics<'tcx>>,
+    param: &hir::GenericParam<'tcx>,
 ) -> GenericParamDef {
     let (name, kind) = match param.kind {
         hir::GenericParamKind::Lifetime { .. } => {
@@ -536,8 +541,8 @@ fn clean_generic_param(
     GenericParamDef { name, kind }
 }
 
-impl Clean<Generics> for hir::Generics<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Generics {
+impl<'tcx> Clean<'tcx, Generics> for hir::Generics<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Generics {
         // Synthetic type-parameters are inserted after normal ones.
         // In order for normal parameters to be able to refer to synthetic ones,
         // scans them first.
@@ -618,10 +623,10 @@ impl Clean<Generics> for hir::Generics<'_> {
     }
 }
 
-fn clean_ty_generics(
-    cx: &mut DocContext<'_>,
+fn clean_ty_generics<'tcx>(
+    cx: &mut DocContext<'tcx>,
     gens: &ty::Generics,
-    preds: ty::GenericPredicates<'_>,
+    preds: ty::GenericPredicates<'tcx>,
 ) -> Generics {
     // Don't populate `cx.impl_trait_bounds` before `clean`ning `where` clauses,
     // since `Clean for ty::Predicate` would consume them.
@@ -784,13 +789,13 @@ fn clean_ty_generics(
     }
 }
 
-fn clean_fn_or_proc_macro(
-    item: &hir::Item<'_>,
-    sig: &hir::FnSig<'_>,
-    generics: &hir::Generics<'_>,
+fn clean_fn_or_proc_macro<'tcx>(
+    item: &hir::Item<'tcx>,
+    sig: &hir::FnSig<'tcx>,
+    generics: &hir::Generics<'tcx>,
     body_id: hir::BodyId,
     name: &mut Symbol,
-    cx: &mut DocContext<'_>,
+    cx: &mut DocContext<'tcx>,
 ) -> ItemKind {
     let attrs = cx.tcx.hir().attrs(item.hir_id());
     let macro_kind = attrs.iter().find_map(|a| {
@@ -868,10 +873,10 @@ fn clean_fn_decl_legacy_const_generics(func: &mut Function, attrs: &[ast::Attrib
     }
 }
 
-fn clean_function(
-    cx: &mut DocContext<'_>,
-    sig: &hir::FnSig<'_>,
-    generics: &hir::Generics<'_>,
+fn clean_function<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    sig: &hir::FnSig<'tcx>,
+    generics: &hir::Generics<'tcx>,
     body_id: hir::BodyId,
 ) -> Function {
     let (generics, decl) = enter_impl_trait(cx, |cx| {
@@ -884,9 +889,9 @@ fn clean_function(
     Function { decl, generics }
 }
 
-fn clean_args_from_types_and_names(
-    cx: &mut DocContext<'_>,
-    types: &[hir::Ty<'_>],
+fn clean_args_from_types_and_names<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    types: &[hir::Ty<'tcx>],
     names: &[Ident],
 ) -> Arguments {
     Arguments {
@@ -904,9 +909,9 @@ fn clean_args_from_types_and_names(
     }
 }
 
-fn clean_args_from_types_and_body_id(
-    cx: &mut DocContext<'_>,
-    types: &[hir::Ty<'_>],
+fn clean_args_from_types_and_body_id<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    types: &[hir::Ty<'tcx>],
     body_id: hir::BodyId,
 ) -> Arguments {
     let body = cx.tcx.hir().body(body_id);
@@ -924,18 +929,18 @@ fn clean_args_from_types_and_body_id(
     }
 }
 
-fn clean_fn_decl_with_args(
-    cx: &mut DocContext<'_>,
-    decl: &hir::FnDecl<'_>,
+fn clean_fn_decl_with_args<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    decl: &hir::FnDecl<'tcx>,
     args: Arguments,
 ) -> FnDecl {
     FnDecl { inputs: args, output: decl.output.clean(cx), c_variadic: decl.c_variadic }
 }
 
-fn clean_fn_decl_from_did_and_sig(
-    cx: &mut DocContext<'_>,
+fn clean_fn_decl_from_did_and_sig<'tcx>(
+    cx: &mut DocContext<'tcx>,
     did: Option<DefId>,
-    sig: ty::PolyFnSig<'_>,
+    sig: ty::PolyFnSig<'tcx>,
 ) -> FnDecl {
     let mut names = did.map_or(&[] as &[_], |did| cx.tcx.fn_arg_names(did)).iter();
 
@@ -964,8 +969,8 @@ fn clean_fn_decl_from_did_and_sig(
     }
 }
 
-impl Clean<FnRetTy> for hir::FnRetTy<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> FnRetTy {
+impl<'tcx> Clean<'tcx, FnRetTy> for hir::FnRetTy<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> FnRetTy {
         match *self {
             Self::Return(ref typ) => Return(typ.clean(cx)),
             Self::DefaultReturn(..) => DefaultReturn,
@@ -973,8 +978,8 @@ impl Clean<FnRetTy> for hir::FnRetTy<'_> {
     }
 }
 
-impl Clean<bool> for hir::IsAuto {
-    fn clean(&self, _: &mut DocContext<'_>) -> bool {
+impl<'tcx> Clean<'tcx, bool> for hir::IsAuto {
+    fn clean(&self, _: &mut DocContext<'tcx>) -> bool {
         match *self {
             hir::IsAuto::Yes => true,
             hir::IsAuto::No => false,
@@ -982,16 +987,16 @@ impl Clean<bool> for hir::IsAuto {
     }
 }
 
-impl Clean<Path> for hir::TraitRef<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Path {
+impl<'tcx> Clean<'tcx, Path> for hir::TraitRef<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Path {
         let path = self.path.clean(cx);
         register_res(cx, path.res);
         path
     }
 }
 
-impl Clean<PolyTrait> for hir::PolyTraitRef<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> PolyTrait {
+impl<'tcx> Clean<'tcx, PolyTrait> for hir::PolyTraitRef<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> PolyTrait {
         PolyTrait {
             trait_: self.trait_ref.clean(cx),
             generic_params: self
@@ -1003,8 +1008,8 @@ impl Clean<PolyTrait> for hir::PolyTraitRef<'_> {
     }
 }
 
-impl Clean<Item> for hir::TraitItem<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Item {
+impl<'tcx> Clean<'tcx, Item> for hir::TraitItem<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Item {
         let local_did = self.def_id.to_def_id();
         cx.with_param_env(local_did, |cx| {
             let inner = match self.kind {
@@ -1050,8 +1055,8 @@ impl Clean<Item> for hir::TraitItem<'_> {
     }
 }
 
-impl Clean<Item> for hir::ImplItem<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Item {
+impl<'tcx> Clean<'tcx, Item> for hir::ImplItem<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Item {
         let local_did = self.def_id.to_def_id();
         cx.with_param_env(local_did, |cx| {
             let inner = match self.kind {
@@ -1091,8 +1096,8 @@ impl Clean<Item> for hir::ImplItem<'_> {
     }
 }
 
-impl Clean<Item> for ty::AssocItem {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Item {
+impl<'tcx> Clean<'tcx, Item> for ty::AssocItem {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Item {
         let tcx = cx.tcx;
         let kind = match self.kind {
             ty::AssocKind::Const => {
@@ -1282,7 +1287,7 @@ impl Clean<Item> for ty::AssocItem {
     }
 }
 
-fn clean_qpath(hir_ty: &hir::Ty<'_>, cx: &mut DocContext<'_>) -> Type {
+fn clean_qpath<'tcx>(hir_ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> Type {
     let hir::Ty { hir_id: _, span, ref kind } = *hir_ty;
     let hir::TyKind::Path(qpath) = kind else { unreachable!() };
 
@@ -1352,7 +1357,10 @@ fn clean_qpath(hir_ty: &hir::Ty<'_>, cx: &mut DocContext<'_>) -> Type {
     }
 }
 
-fn maybe_expand_private_type_alias(cx: &mut DocContext<'_>, path: &hir::Path<'_>) -> Option<Type> {
+fn maybe_expand_private_type_alias<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    path: &hir::Path<'tcx>,
+) -> Option<Type> {
     let Res::Def(DefKind::TyAlias, def_id) = path.res else { return None };
     // Substitute private type aliases
     let def_id = def_id.as_local()?;
@@ -1435,8 +1443,8 @@ fn maybe_expand_private_type_alias(cx: &mut DocContext<'_>, path: &hir::Path<'_>
     Some(cx.enter_alias(substs, |cx| ty.clean(cx)))
 }
 
-impl Clean<Type> for hir::Ty<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Type {
+impl<'tcx> Clean<'tcx, Type> for hir::Ty<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Type {
         use rustc_hir::*;
 
         match self.kind {
@@ -1530,7 +1538,7 @@ fn normalize<'tcx>(cx: &mut DocContext<'tcx>, ty: Ty<'_>) -> Option<Ty<'tcx>> {
     }
 }
 
-fn clean_ty<'tcx>(this: Ty<'tcx>, cx: &mut DocContext<'_>, def_id: Option<DefId>) -> Type {
+fn clean_ty<'tcx>(this: Ty<'tcx>, cx: &mut DocContext<'tcx>, def_id: Option<DefId>) -> Type {
     trace!("cleaning type: {:?}", this);
     let ty = normalize(cx, this).unwrap_or(this);
     match *ty.kind() {
@@ -1715,14 +1723,14 @@ fn clean_ty<'tcx>(this: Ty<'tcx>, cx: &mut DocContext<'_>, def_id: Option<DefId>
     }
 }
 
-impl<'tcx> Clean<Type> for Ty<'tcx> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Type {
+impl<'tcx> Clean<'tcx, Type> for Ty<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Type {
         clean_ty(*self, cx, None)
     }
 }
 
-impl<'tcx> Clean<Constant> for ty::Const<'tcx> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Constant {
+impl<'tcx> Clean<'tcx, Constant> for ty::Const<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Constant {
         // FIXME: instead of storing the stringified expression, store `self` directly instead.
         Constant {
             type_: self.ty().clean(cx),
@@ -1731,15 +1739,15 @@ impl<'tcx> Clean<Constant> for ty::Const<'tcx> {
     }
 }
 
-impl Clean<Item> for hir::FieldDef<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Item {
+impl<'tcx> Clean<'tcx, Item> for hir::FieldDef<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Item {
         let def_id = cx.tcx.hir().local_def_id(self.hir_id).to_def_id();
         clean_field(def_id, self.ident.name, self.ty.clean(cx), cx)
     }
 }
 
-impl Clean<Item> for ty::FieldDef {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Item {
+impl<'tcx> Clean<'tcx, Item> for ty::FieldDef {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Item {
         clean_field(self.did, self.name, cx.tcx.type_of(self.did).clean(cx), cx)
     }
 }
@@ -1765,7 +1773,7 @@ fn is_field_vis_inherited(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     }
 }
 
-impl Clean<Visibility> for ty::Visibility {
+impl<'tcx> Clean<'tcx, Visibility> for ty::Visibility {
     fn clean(&self, _cx: &mut DocContext<'_>) -> Visibility {
         match *self {
             ty::Visibility::Public => Visibility::Public,
@@ -1779,8 +1787,8 @@ impl Clean<Visibility> for ty::Visibility {
     }
 }
 
-impl Clean<VariantStruct> for rustc_hir::VariantData<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> VariantStruct {
+impl<'tcx> Clean<'tcx, VariantStruct> for rustc_hir::VariantData<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> VariantStruct {
         VariantStruct {
             struct_type: CtorKind::from_hir(self),
             fields: self.fields().iter().map(|x| x.clean(cx)).collect(),
@@ -1788,14 +1796,14 @@ impl Clean<VariantStruct> for rustc_hir::VariantData<'_> {
     }
 }
 
-impl Clean<Vec<Item>> for hir::VariantData<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Vec<Item> {
+impl<'tcx> Clean<'tcx, Vec<Item>> for hir::VariantData<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Vec<Item> {
         self.fields().iter().map(|x| x.clean(cx)).collect()
     }
 }
 
-impl Clean<Item> for ty::VariantDef {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Item {
+impl<'tcx> Clean<'tcx, Item> for ty::VariantDef {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Item {
         let kind = match self.ctor_kind {
             CtorKind::Const => Variant::CLike,
             CtorKind::Fn => {
@@ -1813,8 +1821,8 @@ impl Clean<Item> for ty::VariantDef {
     }
 }
 
-impl Clean<Variant> for hir::VariantData<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Variant {
+impl<'tcx> Clean<'tcx, Variant> for hir::VariantData<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Variant {
         match self {
             hir::VariantData::Struct(..) => Variant::Struct(self.clean(cx)),
             hir::VariantData::Tuple(..) => Variant::Tuple(self.clean(cx)),
@@ -1823,14 +1831,14 @@ impl Clean<Variant> for hir::VariantData<'_> {
     }
 }
 
-impl Clean<Path> for hir::Path<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Path {
+impl<'tcx> Clean<'tcx, Path> for hir::Path<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Path {
         Path { res: self.res, segments: self.segments.iter().map(|x| x.clean(cx)).collect() }
     }
 }
 
-impl Clean<GenericArgs> for hir::GenericArgs<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> GenericArgs {
+impl<'tcx> Clean<'tcx, GenericArgs> for hir::GenericArgs<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> GenericArgs {
         if self.parenthesized {
             let output = self.bindings[0].ty().clean(cx);
             let output =
@@ -1858,14 +1866,14 @@ impl Clean<GenericArgs> for hir::GenericArgs<'_> {
     }
 }
 
-impl Clean<PathSegment> for hir::PathSegment<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> PathSegment {
+impl<'tcx> Clean<'tcx, PathSegment> for hir::PathSegment<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> PathSegment {
         PathSegment { name: self.ident.name, args: self.args().clean(cx) }
     }
 }
 
-impl Clean<BareFunctionDecl> for hir::BareFnTy<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> BareFunctionDecl {
+impl<'tcx> Clean<'tcx, BareFunctionDecl> for hir::BareFnTy<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> BareFunctionDecl {
         let (generic_params, decl) = enter_impl_trait(cx, |cx| {
             // NOTE: generics must be cleaned before args
             let generic_params =
@@ -1878,9 +1886,9 @@ impl Clean<BareFunctionDecl> for hir::BareFnTy<'_> {
     }
 }
 
-fn clean_maybe_renamed_item(
-    cx: &mut DocContext<'_>,
-    item: &hir::Item<'_>,
+fn clean_maybe_renamed_item<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    item: &hir::Item<'tcx>,
     renamed: Option<Symbol>,
 ) -> Vec<Item> {
     use hir::ItemKind;
@@ -1961,8 +1969,8 @@ fn clean_maybe_renamed_item(
     })
 }
 
-impl Clean<Item> for hir::Variant<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> Item {
+impl<'tcx> Clean<'tcx, Item> for hir::Variant<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> Item {
         let kind = VariantItem(self.data.clean(cx));
         let what_rustc_thinks =
             Item::from_hir_id_and_parts(self.id, Some(self.ident.name), kind, cx);
@@ -1971,7 +1979,11 @@ impl Clean<Item> for hir::Variant<'_> {
     }
 }
 
-fn clean_impl(impl_: &hir::Impl<'_>, hir_id: hir::HirId, cx: &mut DocContext<'_>) -> Vec<Item> {
+fn clean_impl<'tcx>(
+    impl_: &hir::Impl<'tcx>,
+    hir_id: hir::HirId,
+    cx: &mut DocContext<'tcx>,
+) -> Vec<Item> {
     let tcx = cx.tcx;
     let mut ret = Vec::new();
     let trait_ = impl_.of_trait.as_ref().map(|t| t.clean(cx));
@@ -2009,11 +2021,11 @@ fn clean_impl(impl_: &hir::Impl<'_>, hir_id: hir::HirId, cx: &mut DocContext<'_>
     ret
 }
 
-fn clean_extern_crate(
-    krate: &hir::Item<'_>,
+fn clean_extern_crate<'tcx>(
+    krate: &hir::Item<'tcx>,
     name: Symbol,
     orig_name: Option<Symbol>,
-    cx: &mut DocContext<'_>,
+    cx: &mut DocContext<'tcx>,
 ) -> Vec<Item> {
     // this is the ID of the `extern crate` statement
     let cnum = cx.tcx.extern_mod_stmt_cnum(krate.def_id).unwrap_or(LOCAL_CRATE);
@@ -2059,12 +2071,12 @@ fn clean_extern_crate(
     }]
 }
 
-fn clean_use_statement(
-    import: &hir::Item<'_>,
+fn clean_use_statement<'tcx>(
+    import: &hir::Item<'tcx>,
     name: Symbol,
-    path: &hir::Path<'_>,
+    path: &hir::Path<'tcx>,
     kind: hir::UseKind,
-    cx: &mut DocContext<'_>,
+    cx: &mut DocContext<'tcx>,
 ) -> Vec<Item> {
     // We need this comparison because some imports (for std types for example)
     // are "inserted" as well but directly by the compiler and they should not be
@@ -2172,9 +2184,9 @@ fn clean_use_statement(
     vec![Item::from_def_id_and_parts(import.def_id.to_def_id(), None, ImportItem(inner), cx)]
 }
 
-fn clean_maybe_renamed_foreign_item(
-    cx: &mut DocContext<'_>,
-    item: &hir::ForeignItem<'_>,
+fn clean_maybe_renamed_foreign_item<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    item: &hir::ForeignItem<'tcx>,
     renamed: Option<Symbol>,
 ) -> Item {
     let def_id = item.def_id.to_def_id();
@@ -2205,8 +2217,8 @@ fn clean_maybe_renamed_foreign_item(
     })
 }
 
-impl Clean<TypeBinding> for hir::TypeBinding<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> TypeBinding {
+impl<'tcx> Clean<'tcx, TypeBinding> for hir::TypeBinding<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> TypeBinding {
         TypeBinding {
             assoc: PathSegment { name: self.ident.name, args: self.gen_args.clean(cx) },
             kind: self.kind.clean(cx),
@@ -2214,8 +2226,8 @@ impl Clean<TypeBinding> for hir::TypeBinding<'_> {
     }
 }
 
-impl Clean<TypeBindingKind> for hir::TypeBindingKind<'_> {
-    fn clean(&self, cx: &mut DocContext<'_>) -> TypeBindingKind {
+impl<'tcx> Clean<'tcx, TypeBindingKind> for hir::TypeBindingKind<'tcx> {
+    fn clean(&self, cx: &mut DocContext<'tcx>) -> TypeBindingKind {
         match *self {
             hir::TypeBindingKind::Equality { ref term } => {
                 TypeBindingKind::Equality { term: term.clean(cx) }

src/librustdoc/clean/utils.rs

@@ -75,9 +75,9 @@ pub(crate) fn krate(cx: &mut DocContext<'_>) -> Crate {
     Crate { module, primitives, external_traits: cx.external_traits.clone() }
 }
 
-pub(crate) fn substs_to_args(
-    cx: &mut DocContext<'_>,
-    substs: &[ty::subst::GenericArg<'_>],
+pub(crate) fn substs_to_args<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    substs: &[ty::subst::GenericArg<'tcx>],
     mut skip_first: bool,
 ) -> Vec<GenericArg> {
     let mut ret_val =
@@ -99,12 +99,12 @@ pub(crate) fn substs_to_args(
     ret_val
 }
 
-fn external_generic_args(
-    cx: &mut DocContext<'_>,
+fn external_generic_args<'tcx>(
+    cx: &mut DocContext<'tcx>,
     did: DefId,
     has_self: bool,
     bindings: Vec<TypeBinding>,
-    substs: SubstsRef<'_>,
+    substs: SubstsRef<'tcx>,
 ) -> GenericArgs {
     let args = substs_to_args(cx, &substs, has_self);
 
@@ -127,12 +127,12 @@ fn external_generic_args(
     }
 }
 
-pub(super) fn external_path(
-    cx: &mut DocContext<'_>,
+pub(super) fn external_path<'tcx>(
+    cx: &mut DocContext<'tcx>,
     did: DefId,
     has_self: bool,
     bindings: Vec<TypeBinding>,
-    substs: SubstsRef<'_>,
+    substs: SubstsRef<'tcx>,
 ) -> Path {
     let def_kind = cx.tcx.def_kind(did);
     let name = cx.tcx.item_name(did);
@@ -439,9 +439,9 @@ pub(crate) fn resolve_use_source(cx: &mut DocContext<'_>, path: Path) -> ImportS
     }
 }
 
-pub(crate) fn enter_impl_trait<F, R>(cx: &mut DocContext<'_>, f: F) -> R
+pub(crate) fn enter_impl_trait<'tcx, F, R>(cx: &mut DocContext<'tcx>, f: F) -> R
 where
-    F: FnOnce(&mut DocContext<'_>) -> R,
+    F: FnOnce(&mut DocContext<'tcx>) -> R,
 {
     let old_bounds = mem::take(&mut cx.impl_trait_bounds);
     let r = f(cx);

src/test/ui/parser/else-no-if.rs

@@ -0,0 +1,32 @@
+fn foo() {
+    if true {
+    } else false {
+    //~^ ERROR expected `{`, found keyword `false`
+    }
+}
+
+fn foo2() {
+    if true {
+    } else falsy() {
+    //~^ ERROR expected `{`, found `falsy`
+    }
+}
+
+fn foo3() {
+    if true {
+    } else falsy();
+    //~^ ERROR expected `{`, found `falsy`
+}
+
+fn foo4() {
+    if true {
+    } else loop{}
+    //~^ ERROR expected `{`, found keyword `loop`
+    {}
+}
+
+fn falsy() -> bool {
+    false
+}
+
+fn main() {}

src/test/ui/parser/else-no-if.stderr

@@ -0,0 +1,58 @@
+error: expected `{`, found keyword `false`
+  --> $DIR/else-no-if.rs:3:12
+   |
+LL |     } else false {
+   |       ---- ^^^^^
+   |       |
+   |       expected an `if` or a block after this `else`
+   |
+help: add an `if` if this is the condition to an chained `if` statement after the `else`
+   |
+LL |     } else if false {
+   |            ++
+help: ... otherwise, place this expression inside of a block if it is not an `if` condition
+   |
+LL |     } else { false } {
+   |            +       +
+
+error: expected `{`, found `falsy`
+  --> $DIR/else-no-if.rs:10:12
+   |
+LL |     } else falsy() {
+   |       ---- ^^^^^
+   |       |
+   |       expected an `if` or a block after this `else`
+   |
+help: add an `if` if this is the condition to an chained `if` statement after the `else`
+   |
+LL |     } else if falsy() {
+   |            ++
+help: ... otherwise, place this expression inside of a block if it is not an `if` condition
+   |
+LL |     } else { falsy() } {
+   |            +         +
+
+error: expected `{`, found `falsy`
+  --> $DIR/else-no-if.rs:17:12
+   |
+LL |     } else falsy();
+   |            ^^^^^ expected `{`
+   |
+help: try placing this code inside a block
+   |
+LL |     } else { falsy() };
+   |            +         +
+
+error: expected `{`, found keyword `loop`
+  --> $DIR/else-no-if.rs:23:12
+   |
+LL |     } else loop{}
+   |            ^^^^ expected `{`
+   |
+help: try placing this code inside a block
+   |
+LL |     } else { loop{} }
+   |            +        +
+
+error: aborting due to 4 previous errors
+