From 40ae7b5b8e09da657b62bc849b8bcdf99a1cb210 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Thu, 2 Jun 2022 20:15:05 +0400
Subject: [PATCH 01/12] Parse closure binders

This is first step in implementing RFC 3216.
- Parse `for<'a>` before closures in ast
  - Error in lowering
- Add `closure_lifetime_binder` feature
---
 compiler/rustc_ast/src/ast.rs                 | 27 +++++++-
 compiler/rustc_ast/src/mut_visit.rs           | 18 ++++-
 compiler/rustc_ast/src/visit.rs               | 25 +++++--
 compiler/rustc_ast_lowering/src/expr.rs       | 24 +++++++
 .../rustc_ast_passes/src/ast_validation.rs    |  4 ++
 compiler/rustc_ast_passes/src/feature_gate.rs |  5 ++
 .../rustc_ast_pretty/src/pprust/state/expr.rs | 11 +++
 .../src/assert/context.rs                     |  2 +-
 compiler/rustc_expand/src/build.rs            |  1 +
 compiler/rustc_feature/src/active.rs          |  2 +
 compiler/rustc_lint/src/early.rs              |  2 +-
 compiler/rustc_parse/src/parser/expr.rs       | 48 ++++++-------
 compiler/rustc_resolve/src/def_collector.rs   |  2 +-
 compiler/rustc_resolve/src/late.rs            |  2 +-
 compiler/rustc_span/src/symbol.rs             |  1 +
 src/test/ui-fulldeps/pprust-expr-roundtrip.rs |  1 +
 .../binder/async-closure-with-binder.rs       |  7 ++
 .../binder/async-closure-with-binder.stderr   |  8 +++
 .../ui/closures/binder/implicit-return.rs     |  6 ++
 .../ui/closures/binder/implicit-return.stderr | 10 +++
 ...on-for-introducing-lifetime-into-binder.rs |  7 ++
 ...or-introducing-lifetime-into-binder.stderr | 33 +++++++++
 .../feature-gate-closure_lifetime_binder.rs   | 12 ++++
 ...eature-gate-closure_lifetime_binder.stderr | 67 +++++++++++++++++++
 24 files changed, 287 insertions(+), 38 deletions(-)
 create mode 100644 src/test/ui/closures/binder/async-closure-with-binder.rs
 create mode 100644 src/test/ui/closures/binder/async-closure-with-binder.stderr
 create mode 100644 src/test/ui/closures/binder/implicit-return.rs
 create mode 100644 src/test/ui/closures/binder/implicit-return.stderr
 create mode 100644 src/test/ui/closures/binder/suggestion-for-introducing-lifetime-into-binder.rs
 create mode 100644 src/test/ui/closures/binder/suggestion-for-introducing-lifetime-into-binder.stderr
 create mode 100644 src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.rs
 create mode 100644 src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.stderr

diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index f705d00442227..ac2328a582418 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1390,7 +1390,7 @@ pub enum ExprKind {
     /// A closure (e.g., `move |a, b, c| a + b + c`).
     ///
     /// The final span is the span of the argument block `|...|`.
-    Closure(CaptureBy, Async, Movability, P<FnDecl>, P<Expr>, Span),
+    Closure(ClosureBinder, CaptureBy, Async, Movability, P<FnDecl>, P<Expr>, Span),
     /// A block (`'label: { ... }`).
     Block(P<Block>, Option<Label>),
     /// An async block (`async move { ... }`).
@@ -1518,6 +1518,31 @@ pub enum Movability {
     Movable,
 }
 
+/// Closure lifetime binder, `for<'a, 'b>` in `for<'a, 'b> |_: &'a (), _: &'b ()|`.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum ClosureBinder {
+    /// The binder is not present, all closure lifetimes are inferred.
+    NotPresent,
+    /// The binder is present.
+    For {
+        /// Span of the whole `for<>` clause
+        ///
+        /// ```text
+        /// for<'a, 'b> |_: &'a (), _: &'b ()| { ... }
+        /// ^^^^^^^^^^^ -- this
+        /// ```
+        span: Span,
+
+        /// Lifetimes in the `for<>` closure
+        ///
+        /// ```text
+        /// for<'a, 'b> |_: &'a (), _: &'b ()| { ... }
+        ///     ^^^^^^ -- this
+        /// ```
+        generic_params: P<[GenericParam]>,
+    },
+}
+
 /// Represents a macro invocation. The `path` indicates which macro
 /// is being invoked, and the `args` are arguments passed to it.
 #[derive(Clone, Encodable, Decodable, Debug)]
diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
index 85bb52964865b..d933ea2da9ed7 100644
--- a/compiler/rustc_ast/src/mut_visit.rs
+++ b/compiler/rustc_ast/src/mut_visit.rs
@@ -125,6 +125,10 @@ pub trait MutVisitor: Sized {
         noop_visit_asyncness(a, self);
     }
 
+    fn visit_closure_binder(&mut self, b: &mut ClosureBinder) {
+        noop_visit_closure_binder(b, self);
+    }
+
     fn visit_block(&mut self, b: &mut P<Block>) {
         noop_visit_block(b, self);
     }
@@ -825,6 +829,17 @@ pub fn visit_constness<T: MutVisitor>(constness: &mut Const, vis: &mut T) {
     }
 }
 
+pub fn noop_visit_closure_binder<T: MutVisitor>(binder: &mut ClosureBinder, vis: &mut T) {
+    match binder {
+        ClosureBinder::NotPresent => {}
+        ClosureBinder::For { span: _, generic_params } => {
+            let mut vec = std::mem::take(generic_params).into_vec();
+            vec.flat_map_in_place(|param| vis.flat_map_generic_param(param));
+            *generic_params = P::from_vec(vec);
+        }
+    }
+}
+
 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut Async, vis: &mut T) {
     match asyncness {
         Async::Yes { span: _, closure_id, return_impl_trait_id } => {
@@ -1336,7 +1351,8 @@ pub fn noop_visit_expr<T: MutVisitor>(
             vis.visit_expr(expr);
             arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
         }
-        ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
+        ExprKind::Closure(binder, _capture_by, asyncness, _movability, decl, body, span) => {
+            vis.visit_closure_binder(binder);
             vis.visit_asyncness(asyncness);
             vis.visit_fn_decl(decl);
             vis.visit_expr(body);
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index 2ce8590d7718f..327fc505e99a4 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -56,14 +56,14 @@ pub enum FnKind<'a> {
     Fn(FnCtxt, Ident, &'a FnSig, &'a Visibility, &'a Generics, Option<&'a Block>),
 
     /// E.g., `|x, y| body`.
-    Closure(&'a FnDecl, &'a Expr),
+    Closure(&'a ClosureBinder, &'a FnDecl, &'a Expr),
 }
 
 impl<'a> FnKind<'a> {
     pub fn header(&self) -> Option<&'a FnHeader> {
         match *self {
             FnKind::Fn(_, _, sig, _, _, _) => Some(&sig.header),
-            FnKind::Closure(_, _) => None,
+            FnKind::Closure(_, _, _) => None,
         }
     }
 
@@ -77,7 +77,7 @@ impl<'a> FnKind<'a> {
     pub fn decl(&self) -> &'a FnDecl {
         match self {
             FnKind::Fn(_, _, sig, _, _, _) => &sig.decl,
-            FnKind::Closure(decl, _) => decl,
+            FnKind::Closure(_, decl, _) => decl,
         }
     }
 
@@ -155,6 +155,9 @@ pub trait Visitor<'ast>: Sized {
     fn visit_generics(&mut self, g: &'ast Generics) {
         walk_generics(self, g)
     }
+    fn visit_closure_binder(&mut self, b: &'ast ClosureBinder) {
+        walk_closure_binder(self, b)
+    }
     fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
         walk_where_predicate(self, p)
     }
@@ -636,6 +639,15 @@ pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics
     walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
 }
 
+pub fn walk_closure_binder<'a, V: Visitor<'a>>(visitor: &mut V, binder: &'a ClosureBinder) {
+    match binder {
+        ClosureBinder::NotPresent => {}
+        ClosureBinder::For { span: _, generic_params } => {
+            walk_list!(visitor, visit_generic_param, generic_params)
+        }
+    }
+}
+
 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
     match *predicate {
         WherePredicate::BoundPredicate(WhereBoundPredicate {
@@ -682,7 +694,8 @@ pub fn walk_fn<'a, V: Visitor<'a>>(visitor: &mut V, kind: FnKind<'a>, _span: Spa
             walk_fn_decl(visitor, &sig.decl);
             walk_list!(visitor, visit_block, body);
         }
-        FnKind::Closure(decl, body) => {
+        FnKind::Closure(binder, decl, body) => {
+            visitor.visit_closure_binder(binder);
             walk_fn_decl(visitor, decl);
             visitor.visit_expr(body);
         }
@@ -856,8 +869,8 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
             visitor.visit_expr(subexpression);
             walk_list!(visitor, visit_arm, arms);
         }
-        ExprKind::Closure(_, _, _, ref decl, ref body, _decl_span) => {
-            visitor.visit_fn(FnKind::Closure(decl, body), expression.span, expression.id)
+        ExprKind::Closure(ref binder, _, _, _, ref decl, ref body, _decl_span) => {
+            visitor.visit_fn(FnKind::Closure(binder, decl, body), expression.span, expression.id)
         }
         ExprKind::Block(ref block, ref opt_label) => {
             walk_list!(visitor, visit_label, opt_label);
diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 9e02e7ed3b9cf..7a35660b0af2d 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -155,6 +155,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     self.lower_expr_await(span, expr)
                 }
                 ExprKind::Closure(
+                    ref binder,
                     capture_clause,
                     asyncness,
                     movability,
@@ -164,6 +165,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 ) => {
                     if let Async::Yes { closure_id, .. } = asyncness {
                         self.lower_expr_async_closure(
+                            binder,
                             capture_clause,
                             e.id,
                             closure_id,
@@ -173,6 +175,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         )
                     } else {
                         self.lower_expr_closure(
+                            binder,
                             capture_clause,
                             e.id,
                             movability,
@@ -831,6 +834,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
     fn lower_expr_closure(
         &mut self,
+        binder: &ClosureBinder,
         capture_clause: CaptureBy,
         closure_id: NodeId,
         movability: Movability,
@@ -838,6 +842,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
         body: &Expr,
         fn_decl_span: Span,
     ) -> hir::ExprKind<'hir> {
+        // FIXME(waffle): lower binder
+        if let &ClosureBinder::For { span, .. } = binder {
+            self.sess
+                .struct_span_err(span, "`for<...>` binders for closures are not yet supported")
+                .help("consider removing `for<...>`")
+                .emit();
+        }
+
         let (body, generator_option) = self.with_new_scopes(move |this| {
             let prev = this.current_item;
             this.current_item = Some(fn_decl_span);
@@ -908,6 +920,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
     fn lower_expr_async_closure(
         &mut self,
+        binder: &ClosureBinder,
         capture_clause: CaptureBy,
         closure_id: NodeId,
         inner_closure_id: NodeId,
@@ -915,6 +928,17 @@ impl<'hir> LoweringContext<'_, 'hir> {
         body: &Expr,
         fn_decl_span: Span,
     ) -> hir::ExprKind<'hir> {
+        // FIXME(waffle): lower binder
+        if let &ClosureBinder::For { span, .. } = binder {
+            self.sess
+                .struct_span_err(
+                    span,
+                    "`for<...>` binders for async closures are not yet supported",
+                )
+                .help("consider removing `for<...>`")
+                .emit();
+        }
+
         let outer_decl =
             FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
 
diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index 3942062656fa9..f284bf4650acc 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -1597,6 +1597,10 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 .emit();
         }
 
+        if let FnKind::Closure(ClosureBinder::For { generic_params, .. }, ..) = fk {
+            self.check_late_bound_lifetime_defs(generic_params);
+        }
+
         if let FnKind::Fn(
             _,
             _,
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index fd2dd6cf6c7f1..e69f85eacf7cd 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -744,6 +744,11 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session) {
         "async closures are unstable",
         "to use an async block, remove the `||`: `async {`"
     );
+    gate_all!(
+        closure_lifetime_binder,
+        "`for<...>` binders for closures are experimental",
+        "consider removing `for<...>`"
+    );
     gate_all!(more_qualified_paths, "usage of qualified paths in this context is experimental");
     gate_all!(generators, "yield syntax is experimental");
     gate_all!(raw_ref_op, "raw address of syntax is experimental");
diff --git a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
index 9f44f1b6cc205..ead38caee287f 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
@@ -389,6 +389,7 @@ impl<'a> State<'a> {
                 self.bclose(expr.span, empty);
             }
             ast::ExprKind::Closure(
+                ref binder,
                 capture_clause,
                 asyncness,
                 movability,
@@ -396,6 +397,7 @@ impl<'a> State<'a> {
                 ref body,
                 _,
             ) => {
+                self.print_closure_binder(binder);
                 self.print_movability(movability);
                 self.print_asyncness(asyncness);
                 self.print_capture_clause(capture_clause);
@@ -594,6 +596,15 @@ impl<'a> State<'a> {
         self.end(); // Close enclosing cbox.
     }
 
+    fn print_closure_binder(&mut self, binder: &ast::ClosureBinder) {
+        match binder {
+            ast::ClosureBinder::NotPresent => {}
+            ast::ClosureBinder::For { generic_params, .. } => {
+                self.print_formal_generic_params(&generic_params)
+            }
+        }
+    }
+
     fn print_movability(&mut self, movability: ast::Movability) {
         match movability {
             ast::Movability::Static => self.word_space("static"),
diff --git a/compiler/rustc_builtin_macros/src/assert/context.rs b/compiler/rustc_builtin_macros/src/assert/context.rs
index 9e50d33486cf2..01152ff7df58a 100644
--- a/compiler/rustc_builtin_macros/src/assert/context.rs
+++ b/compiler/rustc_builtin_macros/src/assert/context.rs
@@ -294,7 +294,7 @@ impl<'cx, 'a> Context<'cx, 'a> {
             | ExprKind::Block(_, _)
             | ExprKind::Box(_)
             | ExprKind::Break(_, _)
-            | ExprKind::Closure(_, _, _, _, _, _)
+            | ExprKind::Closure(_, _, _, _, _, _, _)
             | ExprKind::ConstBlock(_)
             | ExprKind::Continue(_)
             | ExprKind::Err
diff --git a/compiler/rustc_expand/src/build.rs b/compiler/rustc_expand/src/build.rs
index 74e9bbeeeafe9..fa3e2a4a5b81c 100644
--- a/compiler/rustc_expand/src/build.rs
+++ b/compiler/rustc_expand/src/build.rs
@@ -520,6 +520,7 @@ impl<'a> ExtCtxt<'a> {
         self.expr(
             span,
             ast::ExprKind::Closure(
+                ast::ClosureBinder::NotPresent,
                 ast::CaptureBy::Ref,
                 ast::Async::No,
                 ast::Movability::Movable,
diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index b54f0ef361a8d..8d19ae2e3f4c3 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -331,6 +331,8 @@ declare_features! (
     (active, cfg_target_thread_local, "1.7.0", Some(29594), None),
     /// Allow conditional compilation depending on rust version
     (active, cfg_version, "1.45.0", Some(64796), None),
+    /// Allows `for<...>` on closures and generators.
+    (active, closure_lifetime_binder, "1.64.0", Some(97362), None),
     /// Allows `#[track_caller]` on closures and generators.
     (active, closure_track_caller, "1.57.0", Some(87417), None),
     /// Allows to use the `#[cmse_nonsecure_entry]` attribute.
diff --git a/compiler/rustc_lint/src/early.rs b/compiler/rustc_lint/src/early.rs
index 5de35dc085601..6c9638400b299 100644
--- a/compiler/rustc_lint/src/early.rs
+++ b/compiler/rustc_lint/src/early.rs
@@ -218,7 +218,7 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
         // Explicitly check for lints associated with 'closure_id', since
         // it does not have a corresponding AST node
         match e.kind {
-            ast::ExprKind::Closure(_, ast::Async::Yes { closure_id, .. }, ..)
+            ast::ExprKind::Closure(_, _, ast::Async::Yes { closure_id, .. }, ..)
             | ast::ExprKind::Async(_, closure_id, ..) => self.check_id(closure_id),
             _ => {}
         }
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 2c43563b10474..c793e7342242d 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -15,10 +15,10 @@ use rustc_ast::util::classify;
 use rustc_ast::util::literal::LitError;
 use rustc_ast::util::parser::{prec_let_scrutinee_needs_par, AssocOp, Fixity};
 use rustc_ast::visit::Visitor;
-use rustc_ast::StmtKind;
 use rustc_ast::{self as ast, AttrStyle, AttrVec, CaptureBy, ExprField, Lit, UnOp, DUMMY_NODE_ID};
 use rustc_ast::{AnonConst, BinOp, BinOpKind, FnDecl, FnRetTy, MacCall, Param, Ty, TyKind};
 use rustc_ast::{Arm, Async, BlockCheckMode, Expr, ExprKind, Label, Movability, RangeLimits};
+use rustc_ast::{ClosureBinder, StmtKind};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::thin_vec::ThinVec;
 use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, PResult};
@@ -1343,11 +1343,7 @@ impl<'a> Parser<'a> {
             self.parse_if_expr(attrs)
         } else if self.check_keyword(kw::For) {
             if self.choose_generics_over_qpath(1) {
-                // NOTE(Centril, eddyb): DO NOT REMOVE! Beyond providing parser recovery,
-                // this is an insurance policy in case we allow qpaths in (tuple-)struct patterns.
-                // When `for <Foo as Bar>::Proj in $expr $block` is wanted,
-                // you can disambiguate in favor of a pattern with `(...)`.
-                self.recover_quantified_closure_expr(attrs)
+                self.parse_closure_expr(attrs)
             } else {
                 assert!(self.eat_keyword(kw::For));
                 self.parse_for_expr(None, self.prev_token.span, attrs)
@@ -2094,29 +2090,21 @@ impl<'a> Parser<'a> {
         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>> {
+    /// Parses a closure expression (e.g., `move |args| expr`).
+    fn parse_closure_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
         let lo = self.token.span;
-        let _ = self.parse_late_bound_lifetime_defs()?;
-        let span_for = lo.to(self.prev_token.span);
-        let closure = self.parse_closure_expr(attrs)?;
 
-        self.struct_span_err(span_for, "cannot introduce explicit parameters for a closure")
-            .span_label(closure.span, "the parameters are attached to this closure")
-            .span_suggestion(
-                span_for,
-                "remove the parameters",
-                "",
-                Applicability::MachineApplicable,
-            )
-            .emit();
+        let binder = if self.check_keyword(kw::For) {
+            let lo = self.token.span;
+            let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
+            let span = lo.to(self.prev_token.span);
 
-        Ok(self.mk_expr_err(lo.to(closure.span)))
-    }
+            self.sess.gated_spans.gate(sym::closure_lifetime_binder, span);
 
-    /// Parses a closure expression (e.g., `move |args| expr`).
-    fn parse_closure_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
-        let lo = self.token.span;
+            ClosureBinder::For { span, generic_params: P::from_vec(lifetime_defs) }
+        } else {
+            ClosureBinder::NotPresent
+        };
 
         let movability =
             if self.eat_keyword(kw::Static) { Movability::Static } else { Movability::Movable };
@@ -2160,7 +2148,15 @@ impl<'a> Parser<'a> {
 
         let closure = self.mk_expr(
             lo.to(body.span),
-            ExprKind::Closure(capture_clause, asyncness, movability, decl, body, lo.to(decl_hi)),
+            ExprKind::Closure(
+                binder,
+                capture_clause,
+                asyncness,
+                movability,
+                decl,
+                body,
+                lo.to(decl_hi),
+            ),
             attrs,
         );
 
diff --git a/compiler/rustc_resolve/src/def_collector.rs b/compiler/rustc_resolve/src/def_collector.rs
index 52706fbb9e6ec..66641fb2cb248 100644
--- a/compiler/rustc_resolve/src/def_collector.rs
+++ b/compiler/rustc_resolve/src/def_collector.rs
@@ -259,7 +259,7 @@ impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
     fn visit_expr(&mut self, expr: &'a Expr) {
         let parent_def = match expr.kind {
             ExprKind::MacCall(..) => return self.visit_macro_invoc(expr.id),
-            ExprKind::Closure(_, asyncness, ..) => {
+            ExprKind::Closure(_, _, asyncness, ..) => {
                 // Async closures desugar to closures inside of closures, so
                 // we must create two defs.
                 let closure_def = self.create_def(expr.id, DefPathData::ClosureExpr, expr.span);
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 640d13ea43547..caf6f8c839232 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -3495,7 +3495,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
             // resolve the arguments within the proper scopes so that usages of them inside the
             // closure are detected as upvars rather than normal closure arg usages.
-            ExprKind::Closure(_, Async::Yes { .. }, _, ref fn_decl, ref body, _span) => {
+            ExprKind::Closure(_, _, Async::Yes { .. }, _, ref fn_decl, ref body, _span) => {
                 self.with_rib(ValueNS, NormalRibKind, |this| {
                     this.with_label_rib(ClosureOrAsyncRibKind, |this| {
                         // Resolve arguments:
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 9b6967621f1dc..4505dd64a10d1 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -459,6 +459,7 @@ symbols! {
         clone_closures,
         clone_from,
         closure,
+        closure_lifetime_binder,
         closure_to_fn_coercion,
         closure_track_caller,
         cmp,
diff --git a/src/test/ui-fulldeps/pprust-expr-roundtrip.rs b/src/test/ui-fulldeps/pprust-expr-roundtrip.rs
index a37d3a32571ed..a679b7b4e1913 100644
--- a/src/test/ui-fulldeps/pprust-expr-roundtrip.rs
+++ b/src/test/ui-fulldeps/pprust-expr-roundtrip.rs
@@ -114,6 +114,7 @@ fn iter_exprs(depth: usize, f: &mut dyn FnMut(P<Expr>)) {
                 let decl = P(FnDecl { inputs: vec![], output: FnRetTy::Default(DUMMY_SP) });
                 iter_exprs(depth - 1, &mut |e| {
                     g(ExprKind::Closure(
+                        ClosureBinder::NotPresent,
                         CaptureBy::Value,
                         Async::No,
                         Movability::Movable,
diff --git a/src/test/ui/closures/binder/async-closure-with-binder.rs b/src/test/ui/closures/binder/async-closure-with-binder.rs
new file mode 100644
index 0000000000000..b9ecbd9e5d676
--- /dev/null
+++ b/src/test/ui/closures/binder/async-closure-with-binder.rs
@@ -0,0 +1,7 @@
+// edition:2021
+#![feature(closure_lifetime_binder)]
+#![feature(async_closure)]
+fn main() {
+    for<'a> async || ();
+    //~^ ERROR `for<...>` binders on `async` closures are not currently supported
+}
diff --git a/src/test/ui/closures/binder/async-closure-with-binder.stderr b/src/test/ui/closures/binder/async-closure-with-binder.stderr
new file mode 100644
index 0000000000000..46420a1775227
--- /dev/null
+++ b/src/test/ui/closures/binder/async-closure-with-binder.stderr
@@ -0,0 +1,8 @@
+error: `for<...>` binders on `async` closures are not currently supported
+  --> $DIR/async-closure-with-binder.rs:5:5
+   |
+LL |     for<'a> async || ();
+   |     ^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/closures/binder/implicit-return.rs b/src/test/ui/closures/binder/implicit-return.rs
new file mode 100644
index 0000000000000..3aefbdcb299b4
--- /dev/null
+++ b/src/test/ui/closures/binder/implicit-return.rs
@@ -0,0 +1,6 @@
+#![feature(closure_lifetime_binder)]
+
+fn main() {
+    let _f = for<'a> |_: &'a ()| {};
+    //~^ implicit return type is forbidden when `for<...>` is present
+}
diff --git a/src/test/ui/closures/binder/implicit-return.stderr b/src/test/ui/closures/binder/implicit-return.stderr
new file mode 100644
index 0000000000000..022a4e027b650
--- /dev/null
+++ b/src/test/ui/closures/binder/implicit-return.stderr
@@ -0,0 +1,10 @@
+error: implicit return type is forbidden when `for<...>` is present
+  --> $DIR/implicit-return.rs:4:34
+   |
+LL |     let _f = for<'a> |_: &'a ()| {};
+   |              -------             ^
+   |              |
+   |              `for<...>` is here
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/closures/binder/suggestion-for-introducing-lifetime-into-binder.rs b/src/test/ui/closures/binder/suggestion-for-introducing-lifetime-into-binder.rs
new file mode 100644
index 0000000000000..b476dd50cc986
--- /dev/null
+++ b/src/test/ui/closures/binder/suggestion-for-introducing-lifetime-into-binder.rs
@@ -0,0 +1,7 @@
+#![feature(closure_lifetime_binder)]
+fn main() {
+    for<> |_: &'a ()| -> () {};
+    //~^ ERROR use of undeclared lifetime name `'a`
+    for<'a> |_: &'b ()| -> () {};
+    //~^ ERROR use of undeclared lifetime name `'b`
+}
diff --git a/src/test/ui/closures/binder/suggestion-for-introducing-lifetime-into-binder.stderr b/src/test/ui/closures/binder/suggestion-for-introducing-lifetime-into-binder.stderr
new file mode 100644
index 0000000000000..1381acc15ca46
--- /dev/null
+++ b/src/test/ui/closures/binder/suggestion-for-introducing-lifetime-into-binder.stderr
@@ -0,0 +1,33 @@
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/suggestion-for-introducing-lifetime-into-binder.rs:3:16
+   |
+LL |     for<> |_: &'a ()| -> () {};
+   |                ^^ undeclared lifetime
+   |
+help: consider introducing lifetime `'a` here
+   |
+LL |     for<'a, > |_: &'a ()| -> () {};
+   |         +++
+help: consider introducing lifetime `'a` here
+   |
+LL | fn main<'a>() {
+   |        ++++
+
+error[E0261]: use of undeclared lifetime name `'b`
+  --> $DIR/suggestion-for-introducing-lifetime-into-binder.rs:5:18
+   |
+LL |     for<'a> |_: &'b ()| -> () {};
+   |                  ^^ undeclared lifetime
+   |
+help: consider introducing lifetime `'b` here
+   |
+LL |     for<'b, 'a> |_: &'b ()| -> () {};
+   |         +++
+help: consider introducing lifetime `'b` here
+   |
+LL | fn main<'b>() {
+   |        ++++
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0261`.
diff --git a/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.rs b/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.rs
new file mode 100644
index 0000000000000..1e2090186a698
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.rs
@@ -0,0 +1,12 @@
+fn main() {
+    for<> || {};
+    //~^ ERROR `for<...>` binders for closures are experimental
+    //~^^ ERROR `for<...>` binders for closures are not yet supported
+    for<'a> || {};
+    //~^ ERROR `for<...>` binders for closures are experimental
+    //~^^ ERROR `for<...>` binders for closures are not yet supported
+    for<'a, 'b> |_: &'a ()| {};
+    //~^ ERROR `for<...>` binders for closures are experimental
+    //~^^ ERROR `for<...>` binders for closures are not yet supported
+    //~^^^ ERROR use of undeclared lifetime name `'a`
+}
diff --git a/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.stderr b/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.stderr
new file mode 100644
index 0000000000000..77ce6f9f2d635
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.stderr
@@ -0,0 +1,67 @@
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/feature-gate-closure_lifetime_binder.rs:8:22
+   |
+LL | fn main() {
+   |        - help: consider introducing lifetime `'a` here: `<'a>`
+...
+LL |     for<'a, 'b> |_: &'a ()| {};
+   |                      ^^ undeclared lifetime
+
+error[E0658]: `for<...>` binders for closures are experimental
+  --> $DIR/feature-gate-closure_lifetime_binder.rs:2:5
+   |
+LL |     for<> || {};
+   |     ^^^^^
+   |
+   = note: see issue #97362 <https://github.com/rust-lang/rust/issues/97362> for more information
+   = help: add `#![feature(closure_lifetime_binder)]` to the crate attributes to enable
+   = help: consider removing `for<...>`
+
+error[E0658]: `for<...>` binders for closures are experimental
+  --> $DIR/feature-gate-closure_lifetime_binder.rs:5:5
+   |
+LL |     for<'a> || {};
+   |     ^^^^^^^
+   |
+   = note: see issue #97362 <https://github.com/rust-lang/rust/issues/97362> for more information
+   = help: add `#![feature(closure_lifetime_binder)]` to the crate attributes to enable
+   = help: consider removing `for<...>`
+
+error[E0658]: `for<...>` binders for closures are experimental
+  --> $DIR/feature-gate-closure_lifetime_binder.rs:8:5
+   |
+LL |     for<'a, 'b> |_: &'a ()| {};
+   |     ^^^^^^^^^^^
+   |
+   = note: see issue #97362 <https://github.com/rust-lang/rust/issues/97362> for more information
+   = help: add `#![feature(closure_lifetime_binder)]` to the crate attributes to enable
+   = help: consider removing `for<...>`
+
+error: `for<...>` binders for closures are not yet supported
+  --> $DIR/feature-gate-closure_lifetime_binder.rs:2:5
+   |
+LL |     for<> || {};
+   |     ^^^^^
+   |
+   = help: consider removing `for<...>`
+
+error: `for<...>` binders for closures are not yet supported
+  --> $DIR/feature-gate-closure_lifetime_binder.rs:5:5
+   |
+LL |     for<'a> || {};
+   |     ^^^^^^^
+   |
+   = help: consider removing `for<...>`
+
+error: `for<...>` binders for closures are not yet supported
+  --> $DIR/feature-gate-closure_lifetime_binder.rs:8:5
+   |
+LL |     for<'a, 'b> |_: &'a ()| {};
+   |     ^^^^^^^^^^^
+   |
+   = help: consider removing `for<...>`
+
+error: aborting due to 7 previous errors
+
+Some errors have detailed explanations: E0261, E0658.
+For more information about an error, try `rustc --explain E0261`.

From 97fcead24219bea0db1d2133ffd347760ec161d8 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Thu, 2 Jun 2022 20:15:41 +0400
Subject: [PATCH 02/12] --bless tests

---
 .../ui/parser/recover-quantified-closure.rs   |  5 +-
 .../parser/recover-quantified-closure.stderr  | 46 +++++++++++++++----
 2 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/src/test/ui/parser/recover-quantified-closure.rs b/src/test/ui/parser/recover-quantified-closure.rs
index 381324738f62b..a2bb7fde8ff19 100644
--- a/src/test/ui/parser/recover-quantified-closure.rs
+++ b/src/test/ui/parser/recover-quantified-closure.rs
@@ -1,10 +1,13 @@
 fn main() {
     for<'a> |x: &'a u8| *x + 1;
-    //~^ ERROR cannot introduce explicit parameters for a closure
+    //~^ ERROR use of undeclared lifetime name `'a`
+    //~^^ ERROR `for<...>` binders for closures are experimental
+    //~^^^ ERROR `for<...>` binders for closures are not yet supported
 }
 
 enum Foo { Bar }
 fn foo(x: impl Iterator<Item = Foo>) {
     for <Foo>::Bar in x {}
     //~^ ERROR expected one of `move`, `static`, `|`
+    //~^^ ERROR `for<...>` binders for closures are experimental
 }
diff --git a/src/test/ui/parser/recover-quantified-closure.stderr b/src/test/ui/parser/recover-quantified-closure.stderr
index 0f01132651648..168307ea65a6b 100644
--- a/src/test/ui/parser/recover-quantified-closure.stderr
+++ b/src/test/ui/parser/recover-quantified-closure.stderr
@@ -1,16 +1,46 @@
-error: cannot introduce explicit parameters for a closure
+error: expected one of `move`, `static`, `|`, or `||`, found `::`
+  --> $DIR/recover-quantified-closure.rs:10:14
+   |
+LL |     for <Foo>::Bar in x {}
+   |              ^^ expected one of `move`, `static`, `|`, or `||`
+
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/recover-quantified-closure.rs:2:18
+   |
+LL | fn main() {
+   |        - help: consider introducing lifetime `'a` here: `<'a>`
+LL |     for<'a> |x: &'a u8| *x + 1;
+   |                  ^^ undeclared lifetime
+
+error[E0658]: `for<...>` binders for closures are experimental
   --> $DIR/recover-quantified-closure.rs:2:5
    |
 LL |     for<'a> |x: &'a u8| *x + 1;
-   |     ^^^^^^^ ------------------ the parameters are attached to this closure
-   |     |
-   |     help: remove the parameters
+   |     ^^^^^^^
+   |
+   = note: see issue #97362 <https://github.com/rust-lang/rust/issues/97362> for more information
+   = help: add `#![feature(closure_lifetime_binder)]` to the crate attributes to enable
+   = help: consider removing `for<...>`
 
-error: expected one of `move`, `static`, `|`, or `||`, found `::`
-  --> $DIR/recover-quantified-closure.rs:8:14
+error[E0658]: `for<...>` binders for closures are experimental
+  --> $DIR/recover-quantified-closure.rs:10:5
    |
 LL |     for <Foo>::Bar in x {}
-   |              ^^ expected one of `move`, `static`, `|`, or `||`
+   |     ^^^^^^^^^
+   |
+   = note: see issue #97362 <https://github.com/rust-lang/rust/issues/97362> for more information
+   = help: add `#![feature(closure_lifetime_binder)]` to the crate attributes to enable
+   = help: consider removing `for<...>`
+
+error: `for<...>` binders for closures are not yet supported
+  --> $DIR/recover-quantified-closure.rs:2:5
+   |
+LL |     for<'a> |x: &'a u8| *x + 1;
+   |     ^^^^^^^
+   |
+   = help: consider removing `for<...>`
 
-error: aborting due to 2 previous errors
+error: aborting due to 5 previous errors
 
+Some errors have detailed explanations: E0261, E0658.
+For more information about an error, try `rustc --explain E0261`.

From f89ef3cf66206b7c0ba0ca134de40b567c7bda83 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Tue, 12 Jul 2022 13:33:25 +0400
Subject: [PATCH 03/12] Comment out expr size check

---
 compiler/rustc_ast/src/ast.rs | 4 ++--
 compiler/rustc_hir/src/hir.rs | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index ac2328a582418..656dff733f6d9 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1112,8 +1112,8 @@ pub struct Expr {
 }
 
 // `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(Expr, 104);
+//#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+//rustc_data_structures::static_assert_size!(Expr, 104); // FIXME
 
 impl Expr {
     /// Returns `true` if this expression would be valid somewhere that expects a value;
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index a2ef158ce8d32..d60ac330ed1bb 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -3479,7 +3479,7 @@ impl<'hir> Node<'hir> {
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 mod size_asserts {
     rustc_data_structures::static_assert_size!(super::Block<'static>, 48);
-    rustc_data_structures::static_assert_size!(super::Expr<'static>, 64);
+    //rustc_data_structures::static_assert_size!(super::Expr<'static>, 64); // FIXME
     rustc_data_structures::static_assert_size!(super::Pat<'static>, 88);
     rustc_data_structures::static_assert_size!(super::QPath<'static>, 24);
     rustc_data_structures::static_assert_size!(super::Ty<'static>, 72);

From c2dbd62c7c60cd4017c9d499101e40c129e4bc61 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Tue, 12 Jul 2022 13:34:24 +0400
Subject: [PATCH 04/12] Lower closure binders to hir & properly check them

---
 compiler/rustc_ast/src/visit.rs               |  2 +-
 compiler/rustc_ast_lowering/src/expr.rs       | 48 +++++++++++-------
 compiler/rustc_hir/src/hir.rs                 | 12 +++++
 compiler/rustc_hir/src/intravisit.rs          | 11 ++++-
 compiler/rustc_hir_pretty/src/lib.rs          | 40 ++++++++++++++-
 compiler/rustc_lint/src/early.rs              |  1 +
 compiler/rustc_resolve/src/late.rs            | 49 ++++++++++++++++---
 compiler/rustc_resolve/src/late/lifetimes.rs  | 49 ++++++++++++++++++-
 .../binder/async-closure-with-binder.rs       |  1 +
 .../binder/async-closure-with-binder.stderr   | 10 +++-
 .../ui/closures/binder/implicit-return.rs     |  2 +-
 .../ui/closures/binder/implicit-return.stderr |  2 +-
 .../feature-gate-closure_lifetime_binder.rs   | 10 ++--
 ...eature-gate-closure_lifetime_binder.stderr | 48 +++---------------
 .../ui/parser/recover-quantified-closure.rs   |  5 +-
 .../parser/recover-quantified-closure.stderr  | 27 ++++------
 16 files changed, 214 insertions(+), 103 deletions(-)

diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index 327fc505e99a4..3f830acbf27a6 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -642,7 +642,7 @@ pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics
 pub fn walk_closure_binder<'a, V: Visitor<'a>>(visitor: &mut V, binder: &'a ClosureBinder) {
     match binder {
         ClosureBinder::NotPresent => {}
-        ClosureBinder::For { span: _, generic_params } => {
+        ClosureBinder::For { generic_params, span: _ } => {
             walk_list!(visitor, visit_generic_param, generic_params)
         }
     }
diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 7a35660b0af2d..995dc6aab5561 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -609,6 +609,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
         // `static |_task_context| -> <ret_ty> { body }`:
         let generator_kind = hir::ExprKind::Closure {
+            binder: &hir::ClosureBinder::Default,
             capture_clause,
             bound_generic_params: &[],
             fn_decl,
@@ -842,15 +843,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
         body: &Expr,
         fn_decl_span: Span,
     ) -> hir::ExprKind<'hir> {
-        // FIXME(waffle): lower binder
-        if let &ClosureBinder::For { span, .. } = binder {
-            self.sess
-                .struct_span_err(span, "`for<...>` binders for closures are not yet supported")
-                .help("consider removing `for<...>`")
-                .emit();
-        }
+        let (binder_clause, generic_params) = self.lower_closure_binder(binder);
 
-        let (body, generator_option) = self.with_new_scopes(move |this| {
+        let (body_id, generator_option) = self.with_new_scopes(move |this| {
             let prev = this.current_item;
             this.current_item = Some(fn_decl_span);
             let mut generator_kind = None;
@@ -865,15 +860,16 @@ impl<'hir> LoweringContext<'_, 'hir> {
             (body_id, generator_option)
         });
 
-        self.with_lifetime_binder(closure_id, &[], |this, bound_generic_params| {
+        self.with_lifetime_binder(closure_id, generic_params, |this, bound_generic_params| {
             // Lower outside new scope to preserve `is_in_loop_condition`.
             let fn_decl = this.lower_fn_decl(decl, None, FnDeclKind::Closure, None);
 
             hir::ExprKind::Closure {
+                binder: binder_clause,
                 capture_clause,
                 bound_generic_params,
                 fn_decl,
-                body,
+                body: body_id,
                 fn_decl_span: this.lower_span(fn_decl_span),
                 movability: generator_option,
             }
@@ -918,6 +914,21 @@ impl<'hir> LoweringContext<'_, 'hir> {
         }
     }
 
+    fn lower_closure_binder<'c>(
+        &mut self,
+        binder: &'c ClosureBinder,
+    ) -> (&'hir hir::ClosureBinder, &'c [GenericParam]) {
+        let (binder, params) = match binder {
+            ClosureBinder::NotPresent => (hir::ClosureBinder::Default, &[][..]),
+            &ClosureBinder::For { span, ref generic_params } => {
+                let span = self.lower_span(span);
+                (hir::ClosureBinder::For { span }, &**generic_params)
+            }
+        };
+
+        (self.arena.alloc(binder), params)
+    }
+
     fn lower_expr_async_closure(
         &mut self,
         binder: &ClosureBinder,
@@ -928,17 +939,15 @@ impl<'hir> LoweringContext<'_, 'hir> {
         body: &Expr,
         fn_decl_span: Span,
     ) -> hir::ExprKind<'hir> {
-        // FIXME(waffle): lower binder
         if let &ClosureBinder::For { span, .. } = binder {
-            self.sess
-                .struct_span_err(
-                    span,
-                    "`for<...>` binders for async closures are not yet supported",
-                )
-                .help("consider removing `for<...>`")
-                .emit();
+            self.tcx.sess.span_err(
+                span,
+                "`for<...>` binders on `async` closures are not currently supported",
+            );
         }
 
+        let (binder_clause, generic_params) = self.lower_closure_binder(binder);
+
         let outer_decl =
             FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
 
@@ -976,13 +985,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
             body_id
         });
 
-        self.with_lifetime_binder(closure_id, &[], |this, bound_generic_params| {
+        self.with_lifetime_binder(closure_id, generic_params, |this, bound_generic_params| {
             // We need to lower the declaration outside the new scope, because we
             // have to conserve the state of being inside a loop condition for the
             // closure argument types.
             let fn_decl = this.lower_fn_decl(&outer_decl, None, FnDeclKind::Closure, None);
 
             hir::ExprKind::Closure {
+                binder: binder_clause,
                 capture_clause,
                 bound_generic_params,
                 fn_decl,
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index d60ac330ed1bb..2252dfd683a41 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -1931,6 +1931,7 @@ pub enum ExprKind<'hir> {
     /// This may also be a generator literal or an `async block` as indicated by the
     /// `Option<Movability>`.
     Closure {
+        binder: &'hir ClosureBinder,
         capture_clause: CaptureBy,
         bound_generic_params: &'hir [GenericParam<'hir>],
         fn_decl: &'hir FnDecl<'hir>,
@@ -2715,6 +2716,17 @@ impl FnRetTy<'_> {
     }
 }
 
+/// Represents `for<...>` binder before a closure
+#[derive(Copy, Clone, Debug, HashStable_Generic)]
+pub enum ClosureBinder {
+    /// Binder is not specified.
+    Default,
+    /// Binder is specified.
+    ///
+    /// Span points to the whole `for<...>`.
+    For { span: Span },
+}
+
 #[derive(Encodable, Debug, HashStable_Generic)]
 pub struct Mod<'hir> {
     pub spans: ModSpans,
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index 531d9f1404021..6eceef56b47d6 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -925,7 +925,7 @@ pub fn walk_fn_kind<'v, V: Visitor<'v>>(visitor: &mut V, function_kind: FnKind<'
         FnKind::ItemFn(_, generics, ..) => {
             visitor.visit_generics(generics);
         }
-        FnKind::Method(..) | FnKind::Closure => {}
+        FnKind::Closure | FnKind::Method(..) => {}
     }
 }
 
@@ -1145,6 +1145,7 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
             walk_list!(visitor, visit_arm, arms);
         }
         ExprKind::Closure {
+            binder: _,
             bound_generic_params,
             ref fn_decl,
             body,
@@ -1153,7 +1154,13 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
             movability: _,
         } => {
             walk_list!(visitor, visit_generic_param, bound_generic_params);
-            visitor.visit_fn(FnKind::Closure, fn_decl, body, expression.span, expression.hir_id)
+            visitor.visit_fn(
+                FnKind::Closure,
+                fn_decl,
+                body,
+                expression.span,
+                expression.hir_id,
+            )
         }
         ExprKind::Block(ref block, ref opt_label) => {
             walk_list!(visitor, visit_label, opt_label);
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
index 50acb0270b0be..5453f4a8c9295 100644
--- a/compiler/rustc_hir_pretty/src/lib.rs
+++ b/compiler/rustc_hir_pretty/src/lib.rs
@@ -6,6 +6,7 @@ use rustc_ast_pretty::pp::Breaks::{Consistent, Inconsistent};
 use rustc_ast_pretty::pp::{self, Breaks};
 use rustc_ast_pretty::pprust::{Comments, PrintState};
 use rustc_hir as hir;
+use rustc_hir::LifetimeParamKind;
 use rustc_hir::{GenericArg, GenericParam, GenericParamKind, Node, Term};
 use rustc_hir::{GenericBound, PatKind, RangeEnd, TraitBoundModifier};
 use rustc_span::source_map::SourceMap;
@@ -1441,6 +1442,7 @@ impl<'a> State<'a> {
                 self.bclose(expr.span);
             }
             hir::ExprKind::Closure {
+                binder,
                 capture_clause,
                 bound_generic_params,
                 fn_decl,
@@ -1448,7 +1450,7 @@ impl<'a> State<'a> {
                 fn_decl_span: _,
                 movability: _,
             } => {
-                self.print_formal_generic_params(bound_generic_params);
+                self.print_closure_binder(binder, bound_generic_params);
                 self.print_capture_clause(capture_clause);
 
                 self.print_closure_params(fn_decl, body);
@@ -2033,6 +2035,42 @@ impl<'a> State<'a> {
         }
     }
 
+    pub fn print_closure_binder(
+        &mut self,
+        binder: &hir::ClosureBinder,
+        generic_params: &[GenericParam<'_>],
+    ) {
+        let generic_params = generic_params
+            .iter()
+            .filter(|p| {
+                matches!(
+                    p,
+                    GenericParam {
+                        kind: GenericParamKind::Lifetime { kind: LifetimeParamKind::Explicit },
+                        ..
+                    }
+                )
+            })
+            .collect::<Vec<_>>();
+
+        match binder {
+            hir::ClosureBinder::Default => {}
+            // we need to distinguish `|...| {}` from `for<> |...| {}` as `for<>` adds additional restrictions
+            hir::ClosureBinder::For { .. } if generic_params.is_empty() => self.word("for<>"),
+            hir::ClosureBinder::For { .. } => {
+                self.word("for");
+                self.word("<");
+
+                self.commasep(Inconsistent, &generic_params, |s, param| {
+                    s.print_generic_param(param)
+                });
+
+                self.word(">");
+                self.nbsp();
+            }
+        }
+    }
+
     pub fn print_bounds<'b>(
         &mut self,
         prefix: &'static str,
diff --git a/compiler/rustc_lint/src/early.rs b/compiler/rustc_lint/src/early.rs
index 6c9638400b299..87cb2651dd314 100644
--- a/compiler/rustc_lint/src/early.rs
+++ b/compiler/rustc_lint/src/early.rs
@@ -154,6 +154,7 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
                 self.check_id(closure_id);
             }
         }
+
         run_early_pass!(self, check_fn_post, fk, span, id);
     }
 
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index caf6f8c839232..80186650fe869 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -844,19 +844,30 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
                             this.in_func_body = previous_state;
                         }
                     }
-                    FnKind::Closure(declaration, body) => {
-                        // We do not have any explicit generic lifetime parameter.
-                        // FIXME(rfc3216): Change when implementing `for<>` bounds on closures.
+                    FnKind::Closure(binder, declaration, body) => {
+                        this.visit_closure_binder(binder);
+
                         this.with_lifetime_rib(
-                            LifetimeRibKind::AnonymousCreateParameter {
-                                binder: fn_id,
-                                report_in_path: false,
+                            match binder {
+                                // We do not have any explicit generic lifetime parameter.
+                                ClosureBinder::NotPresent => {
+                                    LifetimeRibKind::AnonymousCreateParameter {
+                                        binder: fn_id,
+                                        report_in_path: false,
+                                    }
+                                }
+                                ClosureBinder::For { .. } => LifetimeRibKind::AnonymousReportError,
                             },
                             // Add each argument to the rib.
                             |this| this.resolve_params(&declaration.inputs),
                         );
                         this.with_lifetime_rib(
-                            LifetimeRibKind::AnonymousPassThrough(fn_id, true),
+                            match binder {
+                                ClosureBinder::NotPresent => {
+                                    LifetimeRibKind::AnonymousPassThrough(fn_id, true)
+                                }
+                                ClosureBinder::For { .. } => LifetimeRibKind::AnonymousReportError,
+                            },
                             |this| visit::walk_fn_ret_ty(this, &declaration.output),
                         );
 
@@ -891,6 +902,18 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
         }
     }
 
+    fn visit_closure_binder(&mut self, b: &'ast ClosureBinder) {
+        match b {
+            ClosureBinder::NotPresent => {}
+            ClosureBinder::For { generic_params, .. } => {
+                self.visit_generic_params(
+                    &generic_params,
+                    self.diagnostic_metadata.current_self_item.is_some(),
+                );
+            }
+        }
+    }
+
     fn visit_generic_arg(&mut self, arg: &'ast GenericArg) {
         debug!("visit_generic_arg({:?})", arg);
         let prev = replace(&mut self.diagnostic_metadata.currently_processing_generics, true);
@@ -3515,6 +3538,18 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 });
             }
             // For closures, ClosureOrAsyncRibKind is added in visit_fn
+            ExprKind::Closure(ClosureBinder::For { ref generic_params, span }, ..) => {
+                self.with_generic_param_rib(
+                    &generic_params,
+                    NormalRibKind,
+                    LifetimeRibKind::Generics {
+                        binder: expr.id,
+                        kind: LifetimeBinderKind::Function,
+                        span,
+                    },
+                    |this| visit::walk_expr(this, expr),
+                );
+            }
             ExprKind::Closure(..) => visit::walk_expr(self, expr),
             ExprKind::Async(..) => {
                 self.with_label_rib(ClosureOrAsyncRibKind, |this| visit::walk_expr(this, expr));
diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs
index 557dbecfabe09..547255498a096 100644
--- a/compiler/rustc_resolve/src/late/lifetimes.rs
+++ b/compiler/rustc_resolve/src/late/lifetimes.rs
@@ -571,7 +571,51 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
     }
 
     fn visit_expr(&mut self, e: &'tcx hir::Expr<'tcx>) {
-        if let hir::ExprKind::Closure { bound_generic_params, .. } = e.kind {
+        if let hir::ExprKind::Closure { binder, bound_generic_params, fn_decl, .. } = e.kind {
+            if let &hir::ClosureBinder::For { span: for_sp, .. } = binder {
+                fn span_of_infer(ty: &hir::Ty<'_>) -> Option<Span> {
+                    struct V(Option<Span>);
+
+                    impl<'v> Visitor<'v> for V {
+                        fn visit_ty(&mut self, t: &'v hir::Ty<'v>) {
+                            match t.kind {
+                                _ if self.0.is_some() => (),
+                                hir::TyKind::Infer => {
+                                    self.0 = Some(t.span);
+                                }
+                                _ => intravisit::walk_ty(self, t),
+                            }
+                        }
+                    }
+
+                    let mut v = V(None);
+                    v.visit_ty(ty);
+                    v.0
+                }
+
+                let infer_in_rt_sp = match fn_decl.output {
+                    hir::FnRetTy::DefaultReturn(sp) => Some(sp),
+                    hir::FnRetTy::Return(ty) => span_of_infer(ty),
+                };
+
+                let infer_spans = fn_decl
+                    .inputs
+                    .into_iter()
+                    .filter_map(span_of_infer)
+                    .chain(infer_in_rt_sp)
+                    .collect::<Vec<_>>();
+
+                if !infer_spans.is_empty() {
+                    self.tcx.sess
+                        .struct_span_err(
+                            infer_spans,
+                            "implicit types in closure signatures are forbidden when `for<...>` is present",
+                        )
+                        .span_label(for_sp, "`for<...>` is here")
+                        .emit();
+                }
+            }
+
             let next_early_index = self.next_early_index();
             let (lifetimes, binders): (FxIndexMap<LocalDefId, Region>, Vec<_>) =
                 bound_generic_params
@@ -584,6 +628,9 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                         (pair, r)
                     })
                     .unzip();
+
+            // FIXME: missing_named_lifetime_spots
+
             self.map.late_bound_vars.insert(e.hir_id, binders);
             let scope = Scope::Binder {
                 hir_id: e.hir_id,
diff --git a/src/test/ui/closures/binder/async-closure-with-binder.rs b/src/test/ui/closures/binder/async-closure-with-binder.rs
index b9ecbd9e5d676..4fa599d37cbd1 100644
--- a/src/test/ui/closures/binder/async-closure-with-binder.rs
+++ b/src/test/ui/closures/binder/async-closure-with-binder.rs
@@ -4,4 +4,5 @@
 fn main() {
     for<'a> async || ();
     //~^ ERROR `for<...>` binders on `async` closures are not currently supported
+    //~^^ ERROR implicit types in closure signatures are forbidden when `for<...>` is present
 }
diff --git a/src/test/ui/closures/binder/async-closure-with-binder.stderr b/src/test/ui/closures/binder/async-closure-with-binder.stderr
index 46420a1775227..1d4628b1a494a 100644
--- a/src/test/ui/closures/binder/async-closure-with-binder.stderr
+++ b/src/test/ui/closures/binder/async-closure-with-binder.stderr
@@ -4,5 +4,13 @@ error: `for<...>` binders on `async` closures are not currently supported
 LL |     for<'a> async || ();
    |     ^^^^^^^
 
-error: aborting due to previous error
+error: implicit types in closure signatures are forbidden when `for<...>` is present
+  --> $DIR/async-closure-with-binder.rs:5:5
+   |
+LL |     for<'a> async || ();
+   |     -------^^^^^^^^^
+   |     |
+   |     `for<...>` is here
+
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/closures/binder/implicit-return.rs b/src/test/ui/closures/binder/implicit-return.rs
index 3aefbdcb299b4..d34e5721d919b 100644
--- a/src/test/ui/closures/binder/implicit-return.rs
+++ b/src/test/ui/closures/binder/implicit-return.rs
@@ -2,5 +2,5 @@
 
 fn main() {
     let _f = for<'a> |_: &'a ()| {};
-    //~^ implicit return type is forbidden when `for<...>` is present
+    //~^ implicit types in closure signatures are forbidden when `for<...>` is present
 }
diff --git a/src/test/ui/closures/binder/implicit-return.stderr b/src/test/ui/closures/binder/implicit-return.stderr
index 022a4e027b650..5bfb97113344a 100644
--- a/src/test/ui/closures/binder/implicit-return.stderr
+++ b/src/test/ui/closures/binder/implicit-return.stderr
@@ -1,4 +1,4 @@
-error: implicit return type is forbidden when `for<...>` is present
+error: implicit types in closure signatures are forbidden when `for<...>` is present
   --> $DIR/implicit-return.rs:4:34
    |
 LL |     let _f = for<'a> |_: &'a ()| {};
diff --git a/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.rs b/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.rs
index 1e2090186a698..b0b494fa3ff13 100644
--- a/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.rs
+++ b/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.rs
@@ -1,12 +1,8 @@
 fn main() {
-    for<> || {};
+    for<> || -> () {};
     //~^ ERROR `for<...>` binders for closures are experimental
-    //~^^ ERROR `for<...>` binders for closures are not yet supported
-    for<'a> || {};
+    for<'a> || -> () {};
     //~^ ERROR `for<...>` binders for closures are experimental
-    //~^^ ERROR `for<...>` binders for closures are not yet supported
-    for<'a, 'b> |_: &'a ()| {};
+    for<'a, 'b> |_: &'a ()| -> () {};
     //~^ ERROR `for<...>` binders for closures are experimental
-    //~^^ ERROR `for<...>` binders for closures are not yet supported
-    //~^^^ ERROR use of undeclared lifetime name `'a`
 }
diff --git a/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.stderr b/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.stderr
index 77ce6f9f2d635..aea5cfeed0705 100644
--- a/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.stderr
+++ b/src/test/ui/feature-gates/feature-gate-closure_lifetime_binder.stderr
@@ -1,16 +1,7 @@
-error[E0261]: use of undeclared lifetime name `'a`
-  --> $DIR/feature-gate-closure_lifetime_binder.rs:8:22
-   |
-LL | fn main() {
-   |        - help: consider introducing lifetime `'a` here: `<'a>`
-...
-LL |     for<'a, 'b> |_: &'a ()| {};
-   |                      ^^ undeclared lifetime
-
 error[E0658]: `for<...>` binders for closures are experimental
   --> $DIR/feature-gate-closure_lifetime_binder.rs:2:5
    |
-LL |     for<> || {};
+LL |     for<> || -> () {};
    |     ^^^^^
    |
    = note: see issue #97362 <https://github.com/rust-lang/rust/issues/97362> for more information
@@ -18,9 +9,9 @@ LL |     for<> || {};
    = help: consider removing `for<...>`
 
 error[E0658]: `for<...>` binders for closures are experimental
-  --> $DIR/feature-gate-closure_lifetime_binder.rs:5:5
+  --> $DIR/feature-gate-closure_lifetime_binder.rs:4:5
    |
-LL |     for<'a> || {};
+LL |     for<'a> || -> () {};
    |     ^^^^^^^
    |
    = note: see issue #97362 <https://github.com/rust-lang/rust/issues/97362> for more information
@@ -28,40 +19,15 @@ LL |     for<'a> || {};
    = help: consider removing `for<...>`
 
 error[E0658]: `for<...>` binders for closures are experimental
-  --> $DIR/feature-gate-closure_lifetime_binder.rs:8:5
+  --> $DIR/feature-gate-closure_lifetime_binder.rs:6:5
    |
-LL |     for<'a, 'b> |_: &'a ()| {};
+LL |     for<'a, 'b> |_: &'a ()| -> () {};
    |     ^^^^^^^^^^^
    |
    = note: see issue #97362 <https://github.com/rust-lang/rust/issues/97362> for more information
    = help: add `#![feature(closure_lifetime_binder)]` to the crate attributes to enable
    = help: consider removing `for<...>`
 
-error: `for<...>` binders for closures are not yet supported
-  --> $DIR/feature-gate-closure_lifetime_binder.rs:2:5
-   |
-LL |     for<> || {};
-   |     ^^^^^
-   |
-   = help: consider removing `for<...>`
-
-error: `for<...>` binders for closures are not yet supported
-  --> $DIR/feature-gate-closure_lifetime_binder.rs:5:5
-   |
-LL |     for<'a> || {};
-   |     ^^^^^^^
-   |
-   = help: consider removing `for<...>`
-
-error: `for<...>` binders for closures are not yet supported
-  --> $DIR/feature-gate-closure_lifetime_binder.rs:8:5
-   |
-LL |     for<'a, 'b> |_: &'a ()| {};
-   |     ^^^^^^^^^^^
-   |
-   = help: consider removing `for<...>`
-
-error: aborting due to 7 previous errors
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0261, E0658.
-For more information about an error, try `rustc --explain E0261`.
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/parser/recover-quantified-closure.rs b/src/test/ui/parser/recover-quantified-closure.rs
index a2bb7fde8ff19..10af39b700748 100644
--- a/src/test/ui/parser/recover-quantified-closure.rs
+++ b/src/test/ui/parser/recover-quantified-closure.rs
@@ -1,8 +1,7 @@
 fn main() {
     for<'a> |x: &'a u8| *x + 1;
-    //~^ ERROR use of undeclared lifetime name `'a`
-    //~^^ ERROR `for<...>` binders for closures are experimental
-    //~^^^ ERROR `for<...>` binders for closures are not yet supported
+    //~^ ERROR `for<...>` binders for closures are experimental
+    //~^^ ERROR implicit types in closure signatures are forbidden when `for<...>` is present
 }
 
 enum Foo { Bar }
diff --git a/src/test/ui/parser/recover-quantified-closure.stderr b/src/test/ui/parser/recover-quantified-closure.stderr
index 168307ea65a6b..39eec80f658ad 100644
--- a/src/test/ui/parser/recover-quantified-closure.stderr
+++ b/src/test/ui/parser/recover-quantified-closure.stderr
@@ -1,17 +1,9 @@
 error: expected one of `move`, `static`, `|`, or `||`, found `::`
-  --> $DIR/recover-quantified-closure.rs:10:14
+  --> $DIR/recover-quantified-closure.rs:9:14
    |
 LL |     for <Foo>::Bar in x {}
    |              ^^ expected one of `move`, `static`, `|`, or `||`
 
-error[E0261]: use of undeclared lifetime name `'a`
-  --> $DIR/recover-quantified-closure.rs:2:18
-   |
-LL | fn main() {
-   |        - help: consider introducing lifetime `'a` here: `<'a>`
-LL |     for<'a> |x: &'a u8| *x + 1;
-   |                  ^^ undeclared lifetime
-
 error[E0658]: `for<...>` binders for closures are experimental
   --> $DIR/recover-quantified-closure.rs:2:5
    |
@@ -23,7 +15,7 @@ LL |     for<'a> |x: &'a u8| *x + 1;
    = help: consider removing `for<...>`
 
 error[E0658]: `for<...>` binders for closures are experimental
-  --> $DIR/recover-quantified-closure.rs:10:5
+  --> $DIR/recover-quantified-closure.rs:9:5
    |
 LL |     for <Foo>::Bar in x {}
    |     ^^^^^^^^^
@@ -32,15 +24,14 @@ LL |     for <Foo>::Bar in x {}
    = help: add `#![feature(closure_lifetime_binder)]` to the crate attributes to enable
    = help: consider removing `for<...>`
 
-error: `for<...>` binders for closures are not yet supported
-  --> $DIR/recover-quantified-closure.rs:2:5
+error: implicit types in closure signatures are forbidden when `for<...>` is present
+  --> $DIR/recover-quantified-closure.rs:2:25
    |
 LL |     for<'a> |x: &'a u8| *x + 1;
-   |     ^^^^^^^
-   |
-   = help: consider removing `for<...>`
+   |     -------             ^
+   |     |
+   |     `for<...>` is here
 
-error: aborting due to 5 previous errors
+error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0261, E0658.
-For more information about an error, try `rustc --explain E0261`.
+For more information about this error, try `rustc --explain E0658`.

From 0c284843ba23482a2263e1e60b595ead154baae1 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Thu, 30 Jun 2022 13:06:19 +0400
Subject: [PATCH 05/12] make for<> in closures a possible place to suggest
 adding named lifetime

---
 .../rustc_resolve/src/late/diagnostics.rs     |  6 +++-
 compiler/rustc_resolve/src/late/lifetimes.rs  | 34 +++++++++++++++++--
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 03cb1cfcfc9ef..d46f0319f2cc2 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -70,6 +70,8 @@ pub(crate) enum ForLifetimeSpanType {
     BoundTail,
     TypeEmpty,
     TypeTail,
+    ClosureEmpty,
+    ClosureTail,
 }
 
 impl ForLifetimeSpanType {
@@ -77,13 +79,15 @@ impl ForLifetimeSpanType {
         match self {
             Self::BoundEmpty | Self::BoundTail => "bound",
             Self::TypeEmpty | Self::TypeTail => "type",
+            Self::ClosureEmpty | Self::ClosureTail => "closure",
         }
     }
 
     pub(crate) fn suggestion(&self, sugg: &str) -> String {
         match self {
             Self::BoundEmpty | Self::TypeEmpty => format!("for<{}> ", sugg),
-            Self::BoundTail | Self::TypeTail => format!(", {}", sugg),
+            Self::ClosureEmpty => format!("for<{}>", sugg),
+            Self::BoundTail | Self::TypeTail | Self::ClosureTail => format!(", {}", sugg),
         }
     }
 }
diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs
index 547255498a096..8763279a66878 100644
--- a/compiler/rustc_resolve/src/late/lifetimes.rs
+++ b/compiler/rustc_resolve/src/late/lifetimes.rs
@@ -15,7 +15,7 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefIdMap, LocalDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{GenericArg, GenericParam, LifetimeName, Node};
-use rustc_hir::{GenericParamKind, HirIdMap};
+use rustc_hir::{GenericParamKind, HirIdMap, LifetimeParamKind};
 use rustc_middle::hir::map::Map;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::resolve_lifetime::*;
@@ -629,8 +629,6 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                     })
                     .unzip();
 
-            // FIXME: missing_named_lifetime_spots
-
             self.map.late_bound_vars.insert(e.hir_id, binders);
             let scope = Scope::Binder {
                 hir_id: e.hir_id,
@@ -642,11 +640,41 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                 allow_late_bound: true,
                 where_bound_origin: None,
             };
+
+            if let &hir::ClosureBinder::For { span, .. } = binder {
+                let last_lt = bound_generic_params
+                    .iter()
+                    .filter(|p| {
+                        matches!(
+                            p,
+                            GenericParam {
+                                kind: GenericParamKind::Lifetime {
+                                    kind: LifetimeParamKind::Explicit
+                                },
+                                ..
+                            }
+                        )
+                    })
+                    .last();
+                let (span, span_type) = match last_lt {
+                    Some(GenericParam { span: last_sp, .. }) => {
+                        (last_sp.shrink_to_hi(), ForLifetimeSpanType::ClosureTail)
+                    }
+                    None => (span, ForLifetimeSpanType::ClosureEmpty),
+                };
+                self.missing_named_lifetime_spots
+                    .push(MissingLifetimeSpot::HigherRanked { span, span_type });
+            }
+
             self.with(scope, |this| {
                 // a closure has no bounds, so everything
                 // contained within is scoped within its binder.
                 intravisit::walk_expr(this, e)
             });
+
+            if let hir::ClosureBinder::For { .. } = binder {
+                self.missing_named_lifetime_spots.pop();
+            }
         } else {
             intravisit::walk_expr(self, e)
         }

From 577f3c6f52f641a8a8f2b2e39ee9784bbf76d25d Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Fri, 24 Jun 2022 19:57:01 +0400
Subject: [PATCH 06/12] add test for implicit stuff in signatures of closures
 with `for<>`

---
 src/test/ui/closures/binder/implicit-stuff.rs |  27 +++++
 .../ui/closures/binder/implicit-stuff.stderr  | 107 ++++++++++++++++++
 2 files changed, 134 insertions(+)
 create mode 100644 src/test/ui/closures/binder/implicit-stuff.rs
 create mode 100644 src/test/ui/closures/binder/implicit-stuff.stderr

diff --git a/src/test/ui/closures/binder/implicit-stuff.rs b/src/test/ui/closures/binder/implicit-stuff.rs
new file mode 100644
index 0000000000000..09e4c747afee8
--- /dev/null
+++ b/src/test/ui/closures/binder/implicit-stuff.rs
@@ -0,0 +1,27 @@
+#![feature(closure_lifetime_binder)]
+
+fn main() {
+    // Implicit types
+    let _ = for<> || {};                                      //~ ERROR implicit types in closure signatures are forbidden when `for<...>` is present
+    let _ = for<'a> || -> &'a _ { &() };                      //~ ERROR implicit types in closure signatures are forbidden when `for<...>` is present
+    let _ = for<'a> |x| -> &'a () { x };                      //~ ERROR implicit types in closure signatures are forbidden when `for<...>` is present
+    let _ = for<'a> |x: &'a _| -> &'a () { x };               //~ ERROR implicit types in closure signatures are forbidden when `for<...>` is present
+    let _ = for<'a> |x: &'a Vec::<_>| -> &'a Vec::<()> { x }; //~ ERROR implicit types in closure signatures are forbidden when `for<...>` is present
+    let _ = for<'a> |x: &'a Vec<()>| -> &'a Vec<_> { x };     //~ ERROR implicit types in closure signatures are forbidden when `for<...>` is present
+    let _ = for<'a> |x: &'a _| -> &'a &'a () { x };           //~ ERROR implicit types in closure signatures are forbidden when `for<...>` is present
+    let _ = for<'a> |x: &'a _, y, z: _| -> &'a _ {            //~ ERROR implicit types in closure signatures are forbidden when `for<...>` is present
+        let _: &u8 = x;
+        let _: u32 = y;
+        let _: i32 = z;
+        x
+    };
+
+    // Lifetime elision
+    let _ = for<> |_: &()| -> () {};           //~ ERROR `&` without an explicit lifetime name cannot be used here
+    let _ = for<> |x: &()| -> &() { x };       //~ ERROR `&` without an explicit lifetime name cannot be used here
+                                               //~| ERROR `&` without an explicit lifetime name cannot be used here
+    let _ = for<> |x: &'_ ()| -> &'_ () { x }; //~ ERROR `'_` cannot be used here
+                                               //~| ERROR `'_` cannot be used here
+    let _ = for<'a> |x: &()| -> &'a () { x };  //~ ERROR `&` without an explicit lifetime name cannot be used here
+    let _ = for<'a> |x: &'a ()| -> &() { x };  //~ ERROR `&` without an explicit lifetime name cannot be used here
+}
diff --git a/src/test/ui/closures/binder/implicit-stuff.stderr b/src/test/ui/closures/binder/implicit-stuff.stderr
new file mode 100644
index 0000000000000..779a08a44e5a8
--- /dev/null
+++ b/src/test/ui/closures/binder/implicit-stuff.stderr
@@ -0,0 +1,107 @@
+error[E0637]: `&` without an explicit lifetime name cannot be used here
+  --> $DIR/implicit-stuff.rs:20:23
+   |
+LL |     let _ = for<> |_: &()| -> () {};
+   |                       ^ explicit lifetime name needed here
+
+error[E0637]: `&` without an explicit lifetime name cannot be used here
+  --> $DIR/implicit-stuff.rs:21:23
+   |
+LL |     let _ = for<> |x: &()| -> &() { x };
+   |                       ^ explicit lifetime name needed here
+
+error[E0637]: `&` without an explicit lifetime name cannot be used here
+  --> $DIR/implicit-stuff.rs:21:31
+   |
+LL |     let _ = for<> |x: &()| -> &() { x };
+   |                               ^ explicit lifetime name needed here
+
+error[E0637]: `'_` cannot be used here
+  --> $DIR/implicit-stuff.rs:23:24
+   |
+LL |     let _ = for<> |x: &'_ ()| -> &'_ () { x };
+   |                        ^^ `'_` is a reserved lifetime name
+
+error[E0637]: `'_` cannot be used here
+  --> $DIR/implicit-stuff.rs:23:35
+   |
+LL |     let _ = for<> |x: &'_ ()| -> &'_ () { x };
+   |                                   ^^ `'_` is a reserved lifetime name
+
+error[E0637]: `&` without an explicit lifetime name cannot be used here
+  --> $DIR/implicit-stuff.rs:25:25
+   |
+LL |     let _ = for<'a> |x: &()| -> &'a () { x };
+   |                         ^ explicit lifetime name needed here
+
+error[E0637]: `&` without an explicit lifetime name cannot be used here
+  --> $DIR/implicit-stuff.rs:26:36
+   |
+LL |     let _ = for<'a> |x: &'a ()| -> &() { x };
+   |                                    ^ explicit lifetime name needed here
+
+error: implicit types in closure signatures are forbidden when `for<...>` is present
+  --> $DIR/implicit-stuff.rs:5:22
+   |
+LL |     let _ = for<> || {};
+   |             -----    ^
+   |             |
+   |             `for<...>` is here
+
+error: implicit types in closure signatures are forbidden when `for<...>` is present
+  --> $DIR/implicit-stuff.rs:6:31
+   |
+LL |     let _ = for<'a> || -> &'a _ { &() };
+   |             -------           ^
+   |             |
+   |             `for<...>` is here
+
+error: implicit types in closure signatures are forbidden when `for<...>` is present
+  --> $DIR/implicit-stuff.rs:7:22
+   |
+LL |     let _ = for<'a> |x| -> &'a () { x };
+   |             -------  ^
+   |             |
+   |             `for<...>` is here
+
+error: implicit types in closure signatures are forbidden when `for<...>` is present
+  --> $DIR/implicit-stuff.rs:8:29
+   |
+LL |     let _ = for<'a> |x: &'a _| -> &'a () { x };
+   |             -------         ^
+   |             |
+   |             `for<...>` is here
+
+error: implicit types in closure signatures are forbidden when `for<...>` is present
+  --> $DIR/implicit-stuff.rs:9:35
+   |
+LL |     let _ = for<'a> |x: &'a Vec::<_>| -> &'a Vec::<()> { x };
+   |             -------               ^
+   |             |
+   |             `for<...>` is here
+
+error: implicit types in closure signatures are forbidden when `for<...>` is present
+  --> $DIR/implicit-stuff.rs:10:49
+   |
+LL |     let _ = for<'a> |x: &'a Vec<()>| -> &'a Vec<_> { x };
+   |             ------- `for<...>` is here          ^
+
+error: implicit types in closure signatures are forbidden when `for<...>` is present
+  --> $DIR/implicit-stuff.rs:11:29
+   |
+LL |     let _ = for<'a> |x: &'a _| -> &'a &'a () { x };
+   |             -------         ^
+   |             |
+   |             `for<...>` is here
+
+error: implicit types in closure signatures are forbidden when `for<...>` is present
+  --> $DIR/implicit-stuff.rs:12:29
+   |
+LL |     let _ = for<'a> |x: &'a _, y, z: _| -> &'a _ {
+   |             -------         ^  ^     ^         ^
+   |             |
+   |             `for<...>` is here
+
+error: aborting due to 15 previous errors
+
+For more information about this error, try `rustc --explain E0637`.

From 3ebb8529560b9b80f38467bac86d686f5dae4934 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Sun, 3 Jul 2022 19:15:39 +0400
Subject: [PATCH 07/12] Add `LifetimeBinderKind::Closure`

---
 compiler/rustc_resolve/src/late.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 80186650fe869..2abbed944a152 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -268,6 +268,7 @@ enum LifetimeBinderKind {
     WhereBound,
     Item,
     Function,
+    Closure,
     ImplBlock,
 }
 
@@ -281,6 +282,7 @@ impl LifetimeBinderKind {
             Item => "item",
             ImplBlock => "impl block",
             Function => "function",
+            Closure => "closure",
         }
     }
 }
@@ -3544,7 +3546,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                     NormalRibKind,
                     LifetimeRibKind::Generics {
                         binder: expr.id,
-                        kind: LifetimeBinderKind::Function,
+                        kind: LifetimeBinderKind::Closure,
                         span,
                     },
                     |this| visit::walk_expr(this, expr),

From df4fee9841e21ac84335d214af163a1b652ec9a2 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Mon, 11 Jul 2022 23:39:53 +0400
Subject: [PATCH 08/12] Add an indirection for closures in `hir::ExprKind`

This helps bring `hir::Expr` size down, `Closure` was the biggest
variant, especially after `for<>` additions.
---
 compiler/rustc_ast_lowering/src/expr.rs       | 35 +++++++++++--------
 .../rustc_borrowck/src/diagnostics/mod.rs     |  6 ++--
 .../src/diagnostics/region_name.rs            | 12 +++----
 compiler/rustc_hir/src/arena.rs               |  1 +
 compiler/rustc_hir/src/hir.rs                 | 21 ++++++-----
 compiler/rustc_hir/src/intravisit.rs          | 14 +++-----
 compiler/rustc_hir_pretty/src/lib.rs          |  6 ++--
 .../infer/error_reporting/need_type_info.rs   |  4 +--
 compiler/rustc_middle/src/hir/map/mod.rs      | 12 ++++---
 compiler/rustc_mir_build/src/build/mod.rs     |  7 ++--
 compiler/rustc_passes/src/loops.rs            |  8 ++++-
 compiler/rustc_passes/src/reachable.rs        |  5 ++-
 compiler/rustc_resolve/src/late/lifetimes.rs  |  5 ++-
 .../rustc_save_analysis/src/dump_visitor.rs   |  2 +-
 .../src/traits/error_reporting/mod.rs         |  2 +-
 .../error_reporting/on_unimplemented.rs       |  2 +-
 .../src/traits/error_reporting/suggestions.rs |  2 +-
 compiler/rustc_typeck/src/check/callee.rs     | 10 +++---
 compiler/rustc_typeck/src/check/coercion.rs   |  4 +--
 compiler/rustc_typeck/src/check/demand.rs     |  2 +-
 compiler/rustc_typeck/src/check/expr.rs       |  4 +--
 .../rustc_typeck/src/check/fn_ctxt/checks.rs  |  2 +-
 compiler/rustc_typeck/src/check/region.rs     |  2 +-
 compiler/rustc_typeck/src/check/upvar.rs      |  2 +-
 compiler/rustc_typeck/src/check/writeback.rs  |  2 +-
 compiler/rustc_typeck/src/collect.rs          |  8 +++--
 26 files changed, 101 insertions(+), 79 deletions(-)

diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 995dc6aab5561..983efa48a4579 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -608,14 +608,18 @@ impl<'hir> LoweringContext<'_, 'hir> {
         });
 
         // `static |_task_context| -> <ret_ty> { body }`:
-        let generator_kind = hir::ExprKind::Closure {
-            binder: &hir::ClosureBinder::Default,
-            capture_clause,
-            bound_generic_params: &[],
-            fn_decl,
-            body,
-            fn_decl_span: self.lower_span(span),
-            movability: Some(hir::Movability::Static),
+        let generator_kind = {
+            let c = self.arena.alloc(hir::Closure {
+                binder: hir::ClosureBinder::Default,
+                capture_clause,
+                bound_generic_params: &[],
+                fn_decl,
+                body,
+                fn_decl_span: self.lower_span(span),
+                movability: Some(hir::Movability::Static),
+            });
+
+            hir::ExprKind::Closure(c)
         };
         let generator = hir::Expr {
             hir_id: self.lower_node_id(closure_node_id),
@@ -864,7 +868,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             // Lower outside new scope to preserve `is_in_loop_condition`.
             let fn_decl = this.lower_fn_decl(decl, None, FnDeclKind::Closure, None);
 
-            hir::ExprKind::Closure {
+            let c = self.arena.alloc(hir::Closure {
                 binder: binder_clause,
                 capture_clause,
                 bound_generic_params,
@@ -872,7 +876,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 body: body_id,
                 fn_decl_span: this.lower_span(fn_decl_span),
                 movability: generator_option,
-            }
+            });
+
+            hir::ExprKind::Closure(c)
         })
     }
 
@@ -917,7 +923,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     fn lower_closure_binder<'c>(
         &mut self,
         binder: &'c ClosureBinder,
-    ) -> (&'hir hir::ClosureBinder, &'c [GenericParam]) {
+    ) -> (hir::ClosureBinder, &'c [GenericParam]) {
         let (binder, params) = match binder {
             ClosureBinder::NotPresent => (hir::ClosureBinder::Default, &[][..]),
             &ClosureBinder::For { span, ref generic_params } => {
@@ -926,7 +932,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             }
         };
 
-        (self.arena.alloc(binder), params)
+        (binder, params)
     }
 
     fn lower_expr_async_closure(
@@ -991,7 +997,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             // closure argument types.
             let fn_decl = this.lower_fn_decl(&outer_decl, None, FnDeclKind::Closure, None);
 
-            hir::ExprKind::Closure {
+            let c = self.arena.alloc(hir::Closure {
                 binder: binder_clause,
                 capture_clause,
                 bound_generic_params,
@@ -999,7 +1005,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 body,
                 fn_decl_span: this.lower_span(fn_decl_span),
                 movability: None,
-            }
+            });
+            hir::ExprKind::Closure(c)
         })
     }
 
diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs
index 6fea6941085ce..daf4040cc4b52 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mod.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs
@@ -891,7 +891,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(local_did);
         let expr = &self.infcx.tcx.hir().expect_expr(hir_id).kind;
         debug!("closure_span: hir_id={:?} expr={:?}", hir_id, expr);
-        if let hir::ExprKind::Closure { body, fn_decl_span, .. } = expr {
+        if let hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, .. }) = expr {
             for (captured_place, place) in self
                 .infcx
                 .tcx
@@ -904,11 +904,11 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         if target_place == place.as_ref() =>
                     {
                         debug!("closure_span: found captured local {:?}", place);
-                        let body = self.infcx.tcx.hir().body(*body);
+                        let body = self.infcx.tcx.hir().body(body);
                         let generator_kind = body.generator_kind();
 
                         return Some((
-                            *fn_decl_span,
+                            fn_decl_span,
                             generator_kind,
                             captured_place.get_capture_kind_span(self.infcx.tcx),
                             captured_place.get_path_span(self.infcx.tcx),
diff --git a/compiler/rustc_borrowck/src/diagnostics/region_name.rs b/compiler/rustc_borrowck/src/diagnostics/region_name.rs
index e60e11f11df9f..e41af17fbf9b3 100644
--- a/compiler/rustc_borrowck/src/diagnostics/region_name.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/region_name.rs
@@ -325,7 +325,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
                         // Can't have BrEnv in functions, constants or generators.
                         bug!("BrEnv outside of closure.");
                     };
-                    let hir::ExprKind::Closure { fn_decl_span, .. }
+                    let hir::ExprKind::Closure(&hir::Closure { fn_decl_span, .. })
                         = tcx.hir().expect_expr(self.mir_hir_id()).kind
                     else {
                         bug!("Closure is not defined by a closure expr");
@@ -701,16 +701,16 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
 
         let (return_span, mir_description, hir_ty) = match hir.get(mir_hir_id) {
             hir::Node::Expr(hir::Expr {
-                kind: hir::ExprKind::Closure { fn_decl, body, fn_decl_span, .. },
+                kind: hir::ExprKind::Closure(&hir::Closure { fn_decl, body, fn_decl_span, .. }),
                 ..
             }) => {
                 let (mut span, mut hir_ty) = match fn_decl.output {
                     hir::FnRetTy::DefaultReturn(_) => {
-                        (tcx.sess.source_map().end_point(*fn_decl_span), None)
+                        (tcx.sess.source_map().end_point(fn_decl_span), None)
                     }
                     hir::FnRetTy::Return(hir_ty) => (fn_decl.output.span(), Some(hir_ty)),
                 };
-                let mir_description = match hir.body(*body).generator_kind {
+                let mir_description = match hir.body(body).generator_kind {
                     Some(hir::GeneratorKind::Async(gen)) => match gen {
                         hir::AsyncGeneratorKind::Block => " of async block",
                         hir::AsyncGeneratorKind::Closure => " of async closure",
@@ -841,9 +841,9 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
 
         let yield_span = match tcx.hir().get(self.mir_hir_id()) {
             hir::Node::Expr(hir::Expr {
-                kind: hir::ExprKind::Closure { fn_decl_span, .. },
+                kind: hir::ExprKind::Closure(&hir::Closure { fn_decl_span, .. }),
                 ..
-            }) => (tcx.sess.source_map().end_point(*fn_decl_span)),
+            }) => (tcx.sess.source_map().end_point(fn_decl_span)),
             _ => self.body.span,
         };
 
diff --git a/compiler/rustc_hir/src/arena.rs b/compiler/rustc_hir/src/arena.rs
index a6d10f3adae9f..44335b7f42ef9 100644
--- a/compiler/rustc_hir/src/arena.rs
+++ b/compiler/rustc_hir/src/arena.rs
@@ -12,6 +12,7 @@ macro_rules! arena_types {
             [] asm_operand: (rustc_hir::InlineAsmOperand<'tcx>, rustc_span::Span),
             [] asm_template: rustc_ast::InlineAsmTemplatePiece,
             [] attribute: rustc_ast::Attribute,
+            [] closure: rustc_hir::Closure<'tcx>,
             [] block: rustc_hir::Block<'tcx>,
             [] bare_fn_ty: rustc_hir::BareFnTy<'tcx>,
             [] body: rustc_hir::Body<'tcx>,
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index 2252dfd683a41..9d198fbdf74f9 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -922,6 +922,17 @@ pub struct Crate<'hir> {
     pub hir_hash: Fingerprint,
 }
 
+#[derive(Debug, HashStable_Generic)]
+pub struct Closure<'hir> {
+    pub binder: ClosureBinder,
+    pub capture_clause: CaptureBy,
+    pub bound_generic_params: &'hir [GenericParam<'hir>],
+    pub fn_decl: &'hir FnDecl<'hir>,
+    pub body: BodyId,
+    pub fn_decl_span: Span,
+    pub movability: Option<Movability>,
+}
+
 /// A block of statements `{ .. }`, which may have a label (in this case the
 /// `targeted_by_break` field will be `true`) and may be `unsafe` by means of
 /// the `rules` being anything but `DefaultBlock`.
@@ -1930,15 +1941,7 @@ pub enum ExprKind<'hir> {
     ///
     /// This may also be a generator literal or an `async block` as indicated by the
     /// `Option<Movability>`.
-    Closure {
-        binder: &'hir ClosureBinder,
-        capture_clause: CaptureBy,
-        bound_generic_params: &'hir [GenericParam<'hir>],
-        fn_decl: &'hir FnDecl<'hir>,
-        body: BodyId,
-        fn_decl_span: Span,
-        movability: Option<Movability>,
-    },
+    Closure(&'hir Closure<'hir>),
     /// A block (e.g., `'label: { ... }`).
     Block(&'hir Block<'hir>, Option<Label>),
 
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index 6eceef56b47d6..913349e161ddc 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -1144,23 +1144,17 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
             visitor.visit_expr(subexpression);
             walk_list!(visitor, visit_arm, arms);
         }
-        ExprKind::Closure {
+        ExprKind::Closure(&Closure {
             binder: _,
             bound_generic_params,
-            ref fn_decl,
+            fn_decl,
             body,
             capture_clause: _,
             fn_decl_span: _,
             movability: _,
-        } => {
+        }) => {
             walk_list!(visitor, visit_generic_param, bound_generic_params);
-            visitor.visit_fn(
-                FnKind::Closure,
-                fn_decl,
-                body,
-                expression.span,
-                expression.hir_id,
-            )
+            visitor.visit_fn(FnKind::Closure, fn_decl, body, expression.span, expression.hir_id)
         }
         ExprKind::Block(ref block, ref opt_label) => {
             walk_list!(visitor, visit_label, opt_label);
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
index 5453f4a8c9295..0351f70db98fb 100644
--- a/compiler/rustc_hir_pretty/src/lib.rs
+++ b/compiler/rustc_hir_pretty/src/lib.rs
@@ -1441,7 +1441,7 @@ impl<'a> State<'a> {
                 }
                 self.bclose(expr.span);
             }
-            hir::ExprKind::Closure {
+            hir::ExprKind::Closure(&hir::Closure {
                 binder,
                 capture_clause,
                 bound_generic_params,
@@ -1449,7 +1449,7 @@ impl<'a> State<'a> {
                 body,
                 fn_decl_span: _,
                 movability: _,
-            } => {
+            }) => {
                 self.print_closure_binder(binder, bound_generic_params);
                 self.print_capture_clause(capture_clause);
 
@@ -2037,7 +2037,7 @@ impl<'a> State<'a> {
 
     pub fn print_closure_binder(
         &mut self,
-        binder: &hir::ClosureBinder,
+        binder: hir::ClosureBinder,
         generic_params: &[GenericParam<'_>],
     ) {
         let generic_params = generic_params
diff --git a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
index 4d29fc469462c..066bf9681b6bb 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
@@ -6,7 +6,7 @@ use rustc_hir::def::Res;
 use rustc_hir::def::{CtorOf, DefKind, Namespace};
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{self, Visitor};
-use rustc_hir::{Body, Expr, ExprKind, FnRetTy, HirId, Local, LocalSource};
+use rustc_hir::{Body, Closure, Expr, ExprKind, FnRetTy, HirId, Local, LocalSource};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::infer::unify_key::ConstVariableOriginKind;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
@@ -1051,7 +1051,7 @@ impl<'a, 'tcx> Visitor<'tcx> for FindInferSourceVisitor<'a, 'tcx> {
 
         if let Some(node_ty) = self.opt_node_type(expr.hir_id) {
             if let (
-                &ExprKind::Closure { fn_decl, body, fn_decl_span, .. },
+                &ExprKind::Closure(&Closure { fn_decl, body, fn_decl_span, .. }),
                 ty::Closure(_, substs),
             ) = (&expr.kind, node_ty.kind())
             {
diff --git a/compiler/rustc_middle/src/hir/map/mod.rs b/compiler/rustc_middle/src/hir/map/mod.rs
index 3e99ba5742a4b..bd06c20963295 100644
--- a/compiler/rustc_middle/src/hir/map/mod.rs
+++ b/compiler/rustc_middle/src/hir/map/mod.rs
@@ -22,7 +22,7 @@ fn fn_decl<'hir>(node: Node<'hir>) -> Option<&'hir FnDecl<'hir>> {
         Node::Item(Item { kind: ItemKind::Fn(sig, _, _), .. })
         | Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(sig, _), .. })
         | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(sig, _), .. }) => Some(&sig.decl),
-        Node::Expr(Expr { kind: ExprKind::Closure { fn_decl, .. }, .. })
+        Node::Expr(Expr { kind: ExprKind::Closure(Closure { fn_decl, .. }), .. })
         | Node::ForeignItem(ForeignItem { kind: ForeignItemKind::Fn(fn_decl, ..), .. }) => {
             Some(fn_decl)
         }
@@ -54,7 +54,7 @@ pub fn associated_body<'hir>(node: Node<'hir>) -> Option<BodyId> {
             kind: ImplItemKind::Const(_, body) | ImplItemKind::Fn(_, body),
             ..
         })
-        | Node::Expr(Expr { kind: ExprKind::Closure { body, .. }, .. }) => Some(*body),
+        | Node::Expr(Expr { kind: ExprKind::Closure(Closure { body, .. }), .. }) => Some(*body),
 
         Node::AnonConst(constant) => Some(constant.body),
 
@@ -279,8 +279,8 @@ impl<'hir> Map<'hir> {
             }
             Node::Field(_) => DefKind::Field,
             Node::Expr(expr) => match expr.kind {
-                ExprKind::Closure { movability: None, .. } => DefKind::Closure,
-                ExprKind::Closure { movability: Some(_), .. } => DefKind::Generator,
+                ExprKind::Closure(Closure { movability: None, .. }) => DefKind::Closure,
+                ExprKind::Closure(Closure { movability: Some(_), .. }) => DefKind::Generator,
                 _ => bug!("def_kind: unsupported node: {}", self.node_to_string(hir_id)),
             },
             Node::GenericParam(param) => match param.kind {
@@ -1021,7 +1021,9 @@ impl<'hir> Map<'hir> {
                 _ => named_span(item.span, item.ident, None),
             },
             Node::Ctor(_) => return self.opt_span(self.get_parent_node(hir_id)),
-            Node::Expr(Expr { kind: ExprKind::Closure { fn_decl_span, .. }, .. }) => *fn_decl_span,
+            Node::Expr(Expr { kind: ExprKind::Closure(Closure { fn_decl_span, .. }), .. }) => {
+                *fn_decl_span
+            }
             _ => self.span_with_body(hir_id),
         };
         Some(span)
diff --git a/compiler/rustc_mir_build/src/build/mod.rs b/compiler/rustc_mir_build/src/build/mod.rs
index e6d42af9817a1..7ae26cccb3848 100644
--- a/compiler/rustc_mir_build/src/build/mod.rs
+++ b/compiler/rustc_mir_build/src/build/mod.rs
@@ -68,9 +68,10 @@ fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_
 
     // Figure out what primary body this item has.
     let (body_id, return_ty_span, span_with_body) = match tcx.hir().get(id) {
-        Node::Expr(hir::Expr { kind: hir::ExprKind::Closure { fn_decl, body, .. }, .. }) => {
-            (*body, fn_decl.output.span(), None)
-        }
+        Node::Expr(hir::Expr {
+            kind: hir::ExprKind::Closure(hir::Closure { fn_decl, body, .. }),
+            ..
+        }) => (*body, fn_decl.output.span(), None),
         Node::Item(hir::Item {
             kind: hir::ItemKind::Fn(hir::FnSig { decl, .. }, _, body_id),
             span,
diff --git a/compiler/rustc_passes/src/loops.rs b/compiler/rustc_passes/src/loops.rs
index 68b2a052391fa..cdda0e388ddf0 100644
--- a/compiler/rustc_passes/src/loops.rs
+++ b/compiler/rustc_passes/src/loops.rs
@@ -57,7 +57,13 @@ impl<'a, 'hir> Visitor<'hir> for CheckLoopVisitor<'a, 'hir> {
             hir::ExprKind::Loop(ref b, _, source, _) => {
                 self.with_context(Loop(source), |v| v.visit_block(&b));
             }
-            hir::ExprKind::Closure { ref fn_decl, body, fn_decl_span, movability, .. } => {
+            hir::ExprKind::Closure(&hir::Closure {
+                ref fn_decl,
+                body,
+                fn_decl_span,
+                movability,
+                ..
+            }) => {
                 let cx = if let Some(Movability::Static) = movability {
                     AsyncClosure(fn_decl_span)
                 } else {
diff --git a/compiler/rustc_passes/src/reachable.rs b/compiler/rustc_passes/src/reachable.rs
index c830ab11e8e6e..f7e3fac6b2e20 100644
--- a/compiler/rustc_passes/src/reachable.rs
+++ b/compiler/rustc_passes/src/reachable.rs
@@ -273,7 +273,10 @@ impl<'tcx> ReachableContext<'tcx> {
                 }
                 hir::ImplItemKind::TyAlias(_) => {}
             },
-            Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure { body, .. }, .. }) => {
+            Node::Expr(&hir::Expr {
+                kind: hir::ExprKind::Closure(&hir::Closure { body, .. }),
+                ..
+            }) => {
                 self.visit_nested_body(body);
             }
             // Nothing to recurse on for these
diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs
index 8763279a66878..efab44f353d91 100644
--- a/compiler/rustc_resolve/src/late/lifetimes.rs
+++ b/compiler/rustc_resolve/src/late/lifetimes.rs
@@ -571,7 +571,10 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
     }
 
     fn visit_expr(&mut self, e: &'tcx hir::Expr<'tcx>) {
-        if let hir::ExprKind::Closure { binder, bound_generic_params, fn_decl, .. } = e.kind {
+        if let hir::ExprKind::Closure(hir::Closure {
+            binder, bound_generic_params, fn_decl, ..
+        }) = e.kind
+        {
             if let &hir::ClosureBinder::For { span: for_sp, .. } = binder {
                 fn span_of_infer(ty: &hir::Ty<'_>) -> Option<Span> {
                     struct V(Option<Span>);
diff --git a/compiler/rustc_save_analysis/src/dump_visitor.rs b/compiler/rustc_save_analysis/src/dump_visitor.rs
index 6eb2f2d929d57..e3798efc96360 100644
--- a/compiler/rustc_save_analysis/src/dump_visitor.rs
+++ b/compiler/rustc_save_analysis/src/dump_visitor.rs
@@ -1360,7 +1360,7 @@ impl<'tcx> Visitor<'tcx> for DumpVisitor<'tcx> {
                     }
                 }
             }
-            hir::ExprKind::Closure { ref fn_decl, body, .. } => {
+            hir::ExprKind::Closure(&hir::Closure { ref fn_decl, body, .. }) => {
                 let id = format!("${}", ex.hir_id);
 
                 // walk arg and return types
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
index 8efefd476abc9..6de03dcee15e7 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -1084,7 +1084,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         let hir = self.tcx.hir();
         Some(match node {
             Node::Expr(&hir::Expr {
-                kind: hir::ExprKind::Closure { body, fn_decl_span, .. },
+                kind: hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, .. }),
                 ..
             }) => (
                 sm.guess_head_span(fn_decl_span),
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
index 7c9ee64a0c2b0..7e8872d901828 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
@@ -103,7 +103,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                 })
             }),
             hir::Node::Expr(hir::Expr {
-                kind: hir::ExprKind::Closure { body, movability, .. },
+                kind: hir::ExprKind::Closure(hir::Closure { body, movability, .. }),
                 ..
             }) => self.describe_generator(*body).or_else(|| {
                 Some(if movability.is_some() { "an async closure" } else { "a closure" })
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index 31d54b5b40393..57d0d43779a2c 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -785,7 +785,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         // Get the name of the callable and the arguments to be used in the suggestion.
         let (snippet, sugg) = match hir.get_if_local(def_id) {
             Some(hir::Node::Expr(hir::Expr {
-                kind: hir::ExprKind::Closure { fn_decl, fn_decl_span, .. },
+                kind: hir::ExprKind::Closure(hir::Closure { fn_decl, fn_decl_span, .. }),
                 ..
             })) => {
                 err.span_label(*fn_decl_span, "consider calling this closure");
diff --git a/compiler/rustc_typeck/src/check/callee.rs b/compiler/rustc_typeck/src/check/callee.rs
index 2c8be88ef6c92..a6b2877d8b66e 100644
--- a/compiler/rustc_typeck/src/check/callee.rs
+++ b/compiler/rustc_typeck/src/check/callee.rs
@@ -285,29 +285,29 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let parent_node = hir.get(parent_hir_id);
         if let (
             hir::Node::Expr(hir::Expr {
-                kind: hir::ExprKind::Closure { fn_decl_span, body, .. },
+                kind: hir::ExprKind::Closure(&hir::Closure { fn_decl_span, body, .. }),
                 ..
             }),
             hir::ExprKind::Block(..),
         ) = (parent_node, callee_node)
         {
-            let fn_decl_span = if hir.body(*body).generator_kind
+            let fn_decl_span = if hir.body(body).generator_kind
                 == Some(hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Closure))
             {
                 // Actually need to unwrap a few more layers of HIR to get to
                 // the _real_ closure...
                 let async_closure = hir.get_parent_node(hir.get_parent_node(parent_hir_id));
                 if let hir::Node::Expr(hir::Expr {
-                    kind: hir::ExprKind::Closure { fn_decl_span, .. },
+                    kind: hir::ExprKind::Closure(&hir::Closure { fn_decl_span, .. }),
                     ..
                 }) = hir.get(async_closure)
                 {
-                    *fn_decl_span
+                    fn_decl_span
                 } else {
                     return;
                 }
             } else {
-                *fn_decl_span
+                fn_decl_span
             };
 
             let start = fn_decl_span.shrink_to_lo();
diff --git a/compiler/rustc_typeck/src/check/coercion.rs b/compiler/rustc_typeck/src/check/coercion.rs
index acd7e4a92dcc9..9c9a2096ae9a4 100644
--- a/compiler/rustc_typeck/src/check/coercion.rs
+++ b/compiler/rustc_typeck/src/check/coercion.rs
@@ -1577,8 +1577,8 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
         let parent_id = fcx.tcx.hir().get_parent_node(id);
         let parent = fcx.tcx.hir().get(parent_id);
         if let Some(expr) = expression
-            && let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Closure { body, .. }, .. }) = parent
-            && !matches!(fcx.tcx.hir().body(*body).value.kind, hir::ExprKind::Block(..))
+            && let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(&hir::Closure { body, .. }), .. }) = parent
+            && !matches!(fcx.tcx.hir().body(body).value.kind, hir::ExprKind::Block(..))
         {
             fcx.suggest_missing_semicolon(&mut err, expr, expected, true);
         }
diff --git a/compiler/rustc_typeck/src/check/demand.rs b/compiler/rustc_typeck/src/check/demand.rs
index 53ca027bb57f5..83e2b84c20a3b 100644
--- a/compiler/rustc_typeck/src/check/demand.rs
+++ b/compiler/rustc_typeck/src/check/demand.rs
@@ -483,7 +483,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let param_parent = self.tcx.hir().get_parent_node(*param_hir_id);
         let Some(Node::Expr(hir::Expr {
             hir_id: expr_hir_id,
-            kind: hir::ExprKind::Closure { fn_decl: closure_fn_decl, .. },
+            kind: hir::ExprKind::Closure(hir::Closure { fn_decl: closure_fn_decl, .. }),
             ..
         })) = self.tcx.hir().find(param_parent) else {
             return None;
diff --git a/compiler/rustc_typeck/src/check/expr.rs b/compiler/rustc_typeck/src/check/expr.rs
index 45ea04f234288..c97209fe44418 100644
--- a/compiler/rustc_typeck/src/check/expr.rs
+++ b/compiler/rustc_typeck/src/check/expr.rs
@@ -35,7 +35,7 @@ use rustc_hir::def::{CtorKind, DefKind, Res};
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::lang_items::LangItem;
-use rustc_hir::{ExprKind, HirId, QPath};
+use rustc_hir::{Closure, ExprKind, HirId, QPath};
 use rustc_infer::infer;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::InferOk;
@@ -319,7 +319,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ExprKind::Match(discrim, arms, match_src) => {
                 self.check_match(expr, &discrim, arms, expected, match_src)
             }
-            ExprKind::Closure { capture_clause, fn_decl, body, movability, .. } => {
+            ExprKind::Closure(&Closure { capture_clause, fn_decl, body, movability, .. }) => {
                 self.check_expr_closure(expr, capture_clause, &fn_decl, body, movability, expected)
             }
             ExprKind::Block(body, _) => self.check_block_with_expected(&body, expected),
diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs b/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
index 1794446e92aa5..fcb243bc9f2ee 100644
--- a/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
+++ b/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
@@ -1821,7 +1821,7 @@ fn label_fn_like<'tcx>(
     } else {
         match tcx.hir().get_if_local(def_id) {
             Some(hir::Node::Expr(hir::Expr {
-                kind: hir::ExprKind::Closure { fn_decl_span, .. },
+                kind: hir::ExprKind::Closure(hir::Closure { fn_decl_span, .. }),
                 ..
             })) => {
                 let spans: MultiSpan = (*fn_decl_span).into();
diff --git a/compiler/rustc_typeck/src/check/region.rs b/compiler/rustc_typeck/src/check/region.rs
index 9f1368a3e0777..a27dda5fc06e6 100644
--- a/compiler/rustc_typeck/src/check/region.rs
+++ b/compiler/rustc_typeck/src/check/region.rs
@@ -335,7 +335,7 @@ fn resolve_expr<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, expr: &'tcx h
     match expr.kind {
         // Manually recurse over closures and inline consts, because they are the only
         // case of nested bodies that share the parent environment.
-        hir::ExprKind::Closure { body, .. }
+        hir::ExprKind::Closure(&hir::Closure { body, .. })
         | hir::ExprKind::ConstBlock(hir::AnonConst { body, .. }) => {
             let body = visitor.tcx.hir().body(body);
             visitor.visit_body(body);
diff --git a/compiler/rustc_typeck/src/check/upvar.rs b/compiler/rustc_typeck/src/check/upvar.rs
index 74546ed908085..08890f2996722 100644
--- a/compiler/rustc_typeck/src/check/upvar.rs
+++ b/compiler/rustc_typeck/src/check/upvar.rs
@@ -142,7 +142,7 @@ struct InferBorrowKindVisitor<'a, 'tcx> {
 impl<'a, 'tcx> Visitor<'tcx> for InferBorrowKindVisitor<'a, 'tcx> {
     fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
         match expr.kind {
-            hir::ExprKind::Closure { capture_clause, body: body_id, .. } => {
+            hir::ExprKind::Closure(&hir::Closure { capture_clause, body: body_id, .. }) => {
                 let body = self.fcx.tcx.hir().body(body_id);
                 self.visit_body(body);
                 self.fcx.analyze_closure(expr.hir_id, expr.span, body_id, body, capture_clause);
diff --git a/compiler/rustc_typeck/src/check/writeback.rs b/compiler/rustc_typeck/src/check/writeback.rs
index 41d241f84acea..0cbb0e25d0d42 100644
--- a/compiler/rustc_typeck/src/check/writeback.rs
+++ b/compiler/rustc_typeck/src/check/writeback.rs
@@ -263,7 +263,7 @@ impl<'cx, 'tcx> Visitor<'tcx> for WritebackCx<'cx, 'tcx> {
         self.fix_index_builtin_expr(e);
 
         match e.kind {
-            hir::ExprKind::Closure { body, .. } => {
+            hir::ExprKind::Closure(&hir::Closure { body, .. }) => {
                 let body = self.fcx.tcx.hir().body(body);
                 for param in body.params {
                     self.visit_node_id(e.span, param.hir_id);
diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs
index 44b9c8392f86b..40ac7424be865 100644
--- a/compiler/rustc_typeck/src/collect.rs
+++ b/compiler/rustc_typeck/src/collect.rs
@@ -1717,8 +1717,10 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
     // provide junk type parameter defs - the only place that
     // cares about anything but the length is instantiation,
     // and we don't do that for closures.
-    if let Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure { movability: gen, .. }, .. }) =
-        node
+    if let Node::Expr(&hir::Expr {
+        kind: hir::ExprKind::Closure(hir::Closure { movability: gen, .. }),
+        ..
+    }) = node
     {
         let dummy_args = if gen.is_some() {
             &["<resume_ty>", "<yield_ty>", "<return_ty>", "<witness>", "<upvars>"][..]
@@ -2564,7 +2566,7 @@ fn is_foreign_item(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
 fn generator_kind(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::GeneratorKind> {
     match tcx.hir().get_if_local(def_id) {
         Some(Node::Expr(&rustc_hir::Expr {
-            kind: rustc_hir::ExprKind::Closure { body, .. },
+            kind: rustc_hir::ExprKind::Closure(&rustc_hir::Closure { body, .. }),
             ..
         })) => tcx.hir().body(body).generator_kind(),
         Some(_) => None,

From d2923b40076ee53c0ad8e5afcbe641fe1a0ce52c Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Mon, 11 Jul 2022 23:40:35 +0400
Subject: [PATCH 09/12] Add back expr size checks

---
 compiler/rustc_ast/src/ast.rs | 4 ++--
 compiler/rustc_hir/src/hir.rs | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 656dff733f6d9..ac2328a582418 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1112,8 +1112,8 @@ pub struct Expr {
 }
 
 // `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
-//#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-//rustc_data_structures::static_assert_size!(Expr, 104); // FIXME
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+rustc_data_structures::static_assert_size!(Expr, 104);
 
 impl Expr {
     /// Returns `true` if this expression would be valid somewhere that expects a value;
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index 9d198fbdf74f9..8ee931b264ead 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -3494,7 +3494,7 @@ impl<'hir> Node<'hir> {
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 mod size_asserts {
     rustc_data_structures::static_assert_size!(super::Block<'static>, 48);
-    //rustc_data_structures::static_assert_size!(super::Expr<'static>, 64); // FIXME
+    rustc_data_structures::static_assert_size!(super::Expr<'static>, 56);
     rustc_data_structures::static_assert_size!(super::Pat<'static>, 88);
     rustc_data_structures::static_assert_size!(super::QPath<'static>, 24);
     rustc_data_structures::static_assert_size!(super::Ty<'static>, 72);

From b504a18563a3a35c91ecb6ebc539aa94856f7f93 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Thu, 30 Jun 2022 17:40:38 +0400
Subject: [PATCH 10/12] implement rustfmt formatting for `for<>` closure
 binders

---
 src/tools/rustfmt/src/closures.rs | 33 +++++++++++++++++++++++++------
 src/tools/rustfmt/src/expr.rs     | 16 ++++++++++-----
 src/tools/rustfmt/src/types.rs    |  2 +-
 src/tools/rustfmt/src/utils.rs    |  2 +-
 4 files changed, 40 insertions(+), 13 deletions(-)

diff --git a/src/tools/rustfmt/src/closures.rs b/src/tools/rustfmt/src/closures.rs
index e688db1c39d7c..88a6bebb68c84 100644
--- a/src/tools/rustfmt/src/closures.rs
+++ b/src/tools/rustfmt/src/closures.rs
@@ -11,6 +11,7 @@ use crate::overflow::OverflowableItem;
 use crate::rewrite::{Rewrite, RewriteContext};
 use crate::shape::Shape;
 use crate::source_map::SpanUtils;
+use crate::types::rewrite_lifetime_param;
 use crate::utils::{last_line_width, left_most_sub_expr, stmt_expr, NodeIdExt};
 
 // This module is pretty messy because of the rules around closures and blocks:
@@ -24,6 +25,7 @@ use crate::utils::{last_line_width, left_most_sub_expr, stmt_expr, NodeIdExt};
 //     can change whether it is treated as an expression or statement.
 
 pub(crate) fn rewrite_closure(
+    binder: &ast::ClosureBinder,
     capture: ast::CaptureBy,
     is_async: &ast::Async,
     movability: ast::Movability,
@@ -36,7 +38,7 @@ pub(crate) fn rewrite_closure(
     debug!("rewrite_closure {:?}", body);
 
     let (prefix, extra_offset) = rewrite_closure_fn_decl(
-        capture, is_async, movability, fn_decl, body, span, context, shape,
+        binder, capture, is_async, movability, fn_decl, body, span, context, shape,
     )?;
     // 1 = space between `|...|` and body.
     let body_shape = shape.offset_left(extra_offset)?;
@@ -227,6 +229,7 @@ fn rewrite_closure_block(
 
 // Return type is (prefix, extra_offset)
 fn rewrite_closure_fn_decl(
+    binder: &ast::ClosureBinder,
     capture: ast::CaptureBy,
     asyncness: &ast::Async,
     movability: ast::Movability,
@@ -236,6 +239,17 @@ fn rewrite_closure_fn_decl(
     context: &RewriteContext<'_>,
     shape: Shape,
 ) -> Option<(String, usize)> {
+    let binder = match binder {
+        ast::ClosureBinder::For { generic_params, .. } if generic_params.is_empty() => {
+            "for<> ".to_owned()
+        }
+        ast::ClosureBinder::For { generic_params, .. } => {
+            let lifetime_str = rewrite_lifetime_param(context, shape, generic_params)?;
+            format!("for<{lifetime_str}> ")
+        }
+        ast::ClosureBinder::NotPresent => "".to_owned(),
+    };
+
     let immovable = if movability == ast::Movability::Static {
         "static "
     } else {
@@ -250,7 +264,7 @@ fn rewrite_closure_fn_decl(
     // 4 = "|| {".len(), which is overconservative when the closure consists of
     // a single expression.
     let nested_shape = shape
-        .shrink_left(immovable.len() + is_async.len() + mover.len())?
+        .shrink_left(binder.len() + immovable.len() + is_async.len() + mover.len())?
         .sub_width(4)?;
 
     // 1 = |
@@ -288,7 +302,7 @@ fn rewrite_closure_fn_decl(
         .tactic(tactic)
         .preserve_newline(true);
     let list_str = write_list(&item_vec, &fmt)?;
-    let mut prefix = format!("{}{}{}|{}|", immovable, is_async, mover, list_str);
+    let mut prefix = format!("{}{}{}{}|{}|", binder, immovable, is_async, mover, list_str);
 
     if !ret_str.is_empty() {
         if prefix.contains('\n') {
@@ -312,8 +326,15 @@ pub(crate) fn rewrite_last_closure(
     expr: &ast::Expr,
     shape: Shape,
 ) -> Option<String> {
-    if let ast::ExprKind::Closure(capture, ref is_async, movability, ref fn_decl, ref body, _) =
-        expr.kind
+    if let ast::ExprKind::Closure(
+        ref binder,
+        capture,
+        ref is_async,
+        movability,
+        ref fn_decl,
+        ref body,
+        _,
+    ) = expr.kind
     {
         let body = match body.kind {
             ast::ExprKind::Block(ref block, _)
@@ -326,7 +347,7 @@ pub(crate) fn rewrite_last_closure(
             _ => body,
         };
         let (prefix, extra_offset) = rewrite_closure_fn_decl(
-            capture, is_async, movability, fn_decl, body, expr.span, context, shape,
+            binder, capture, is_async, movability, fn_decl, body, expr.span, context, shape,
         )?;
         // If the closure goes multi line before its body, do not overflow the closure.
         if prefix.contains('\n') {
diff --git a/src/tools/rustfmt/src/expr.rs b/src/tools/rustfmt/src/expr.rs
index e4cc93026f10b..a7b73ba78c59e 100644
--- a/src/tools/rustfmt/src/expr.rs
+++ b/src/tools/rustfmt/src/expr.rs
@@ -203,11 +203,17 @@ pub(crate) fn format_expr(
                 Some("yield".to_string())
             }
         }
-        ast::ExprKind::Closure(capture, ref is_async, movability, ref fn_decl, ref body, _) => {
-            closures::rewrite_closure(
-                capture, is_async, movability, fn_decl, body, expr.span, context, shape,
-            )
-        }
+        ast::ExprKind::Closure(
+            ref binder,
+            capture,
+            ref is_async,
+            movability,
+            ref fn_decl,
+            ref body,
+            _,
+        ) => closures::rewrite_closure(
+            binder, capture, is_async, movability, fn_decl, body, expr.span, context, shape,
+        ),
         ast::ExprKind::Try(..)
         | ast::ExprKind::Field(..)
         | ast::ExprKind::MethodCall(..)
diff --git a/src/tools/rustfmt/src/types.rs b/src/tools/rustfmt/src/types.rs
index 64a201e45ddd4..2627886db109d 100644
--- a/src/tools/rustfmt/src/types.rs
+++ b/src/tools/rustfmt/src/types.rs
@@ -1067,7 +1067,7 @@ pub(crate) fn can_be_overflowed_type(
 }
 
 /// Returns `None` if there is no `LifetimeDef` in the given generic parameters.
-fn rewrite_lifetime_param(
+pub(crate) fn rewrite_lifetime_param(
     context: &RewriteContext<'_>,
     shape: Shape,
     generic_params: &[ast::GenericParam],
diff --git a/src/tools/rustfmt/src/utils.rs b/src/tools/rustfmt/src/utils.rs
index 4b26f4e40df98..cd852855602e8 100644
--- a/src/tools/rustfmt/src/utils.rs
+++ b/src/tools/rustfmt/src/utils.rs
@@ -479,7 +479,7 @@ pub(crate) fn is_block_expr(context: &RewriteContext<'_>, expr: &ast::Expr, repr
         | ast::ExprKind::Binary(_, _, ref expr)
         | ast::ExprKind::Index(_, ref expr)
         | ast::ExprKind::Unary(_, ref expr)
-        | ast::ExprKind::Closure(_, _, _, _, ref expr, _)
+        | ast::ExprKind::Closure(_, _, _, _, _, ref expr, _)
         | ast::ExprKind::Try(ref expr)
         | ast::ExprKind::Yield(Some(ref expr)) => is_block_expr(context, expr, repr),
         // This can only be a string lit

From 30a3673478e224f74d5520ed24c3a9223fe82fad Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Sun, 3 Jul 2022 16:11:46 +0400
Subject: [PATCH 11/12] Add rustfmt test for formatting `for<>` before closures

---
 src/tools/rustfmt/tests/source/closure.rs | 10 ++++++++++
 src/tools/rustfmt/tests/target/closure.rs |  6 ++++++
 2 files changed, 16 insertions(+)

diff --git a/src/tools/rustfmt/tests/source/closure.rs b/src/tools/rustfmt/tests/source/closure.rs
index e93cc3fb40f59..b2d28b305d0ad 100644
--- a/src/tools/rustfmt/tests/source/closure.rs
+++ b/src/tools/rustfmt/tests/source/closure.rs
@@ -51,6 +51,16 @@ fn main() {
                 "--emit=dep-info"
             } else { a }
         });
+
+    for<>          || -> () {};
+    for<         >|| -> () {};
+    for<
+>   || -> () {};
+
+for<   'a
+   ,'b,
+'c  >   |_: &'a (), _: &'b (), _: &'c ()| -> () {};
+
 }
 
 fn issue311() {
diff --git a/src/tools/rustfmt/tests/target/closure.rs b/src/tools/rustfmt/tests/target/closure.rs
index f3107d19c2fbf..e8b4ff7a96bb8 100644
--- a/src/tools/rustfmt/tests/target/closure.rs
+++ b/src/tools/rustfmt/tests/target/closure.rs
@@ -71,6 +71,12 @@ fn main() {
             a
         }
     });
+
+    for<> || -> () {};
+    for<> || -> () {};
+    for<> || -> () {};
+
+    for<'a, 'b, 'c> |_: &'a (), _: &'b (), _: &'c ()| -> () {};
 }
 
 fn issue311() {

From 9aa142b5f1cf85e9941f7f9a35caa604500dab8b Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Thu, 30 Jun 2022 14:18:51 +0400
Subject: [PATCH 12/12] Fix clippy build

---
 .../clippy_lints/src/blocks_in_if_conditions.rs     |  4 ++--
 src/tools/clippy/clippy_lints/src/bytecount.rs      |  4 ++--
 src/tools/clippy/clippy_lints/src/eta_reduction.rs  |  4 ++--
 src/tools/clippy/clippy_lints/src/infinite_iter.rs  |  4 ++--
 .../clippy_lints/src/loops/needless_range_loop.rs   |  4 ++--
 .../clippy_lints/src/loops/while_let_on_iterator.rs |  8 ++++----
 .../clippy/clippy_lints/src/manual_async_fn.rs      |  4 ++--
 src/tools/clippy/clippy_lints/src/manual_ok_or.rs   |  4 ++--
 src/tools/clippy/clippy_lints/src/manual_retain.rs  |  2 +-
 src/tools/clippy/clippy_lints/src/map_clone.rs      |  2 +-
 src/tools/clippy/clippy_lints/src/map_err_ignore.rs |  6 +++---
 src/tools/clippy/clippy_lints/src/map_unit_fn.rs    |  2 +-
 .../clippy_lints/src/methods/bind_instead_of_map.rs |  2 +-
 .../clippy/clippy_lints/src/methods/filter_map.rs   | 10 +++++-----
 .../clippy_lints/src/methods/option_as_ref_deref.rs |  2 +-
 .../clippy_lints/src/methods/option_map_or_none.rs  |  2 +-
 .../clippy_lints/src/methods/search_is_some.rs      |  2 +-
 .../src/methods/unnecessary_filter_map.rs           |  2 +-
 .../clippy_lints/src/methods/unnecessary_fold.rs    |  2 +-
 .../src/methods/unnecessary_lazy_eval.rs            |  2 +-
 .../clippy/clippy_lints/src/needless_for_each.rs    |  4 ++--
 .../clippy_lints/src/only_used_in_recursion.rs      |  4 ++--
 .../clippy_lints/src/redundant_closure_call.rs      |  2 +-
 .../src/suspicious_operation_groupings.rs           |  2 +-
 .../clippy_lints/src/unit_return_expecting_ord.rs   |  4 ++--
 .../clippy/clippy_lints/src/unnecessary_sort_by.rs  |  4 ++--
 src/tools/clippy/clippy_lints/src/utils/author.rs   |  6 +++---
 src/tools/clippy/clippy_utils/src/ast_utils.rs      | 13 +++++++++++--
 src/tools/clippy/clippy_utils/src/hir_utils.rs      |  6 +++---
 src/tools/clippy/clippy_utils/src/lib.rs            | 12 ++++++------
 src/tools/clippy/clippy_utils/src/sugg.rs           |  4 ++--
 31 files changed, 71 insertions(+), 62 deletions(-)

diff --git a/src/tools/clippy/clippy_lints/src/blocks_in_if_conditions.rs b/src/tools/clippy/clippy_lints/src/blocks_in_if_conditions.rs
index 4b3a04f1255b9..ad206b5fb304f 100644
--- a/src/tools/clippy/clippy_lints/src/blocks_in_if_conditions.rs
+++ b/src/tools/clippy/clippy_lints/src/blocks_in_if_conditions.rs
@@ -6,7 +6,7 @@ use clippy_utils::ty::implements_trait;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_expr, Visitor};
-use rustc_hir::{BlockCheckMode, Expr, ExprKind};
+use rustc_hir::{BlockCheckMode, Closure, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -51,7 +51,7 @@ struct ExVisitor<'a, 'tcx> {
 
 impl<'a, 'tcx> Visitor<'tcx> for ExVisitor<'a, 'tcx> {
     fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
-        if let ExprKind::Closure { body, .. } = expr.kind {
+        if let ExprKind::Closure(&Closure { body, .. }) = expr.kind {
             // do not lint if the closure is called using an iterator (see #1141)
             if_chain! {
                 if let Some(parent) = get_parent_expr(self.cx, expr);
diff --git a/src/tools/clippy/clippy_lints/src/bytecount.rs b/src/tools/clippy/clippy_lints/src/bytecount.rs
index 4e530256321cc..326ce34082af7 100644
--- a/src/tools/clippy/clippy_lints/src/bytecount.rs
+++ b/src/tools/clippy/clippy_lints/src/bytecount.rs
@@ -5,7 +5,7 @@ use clippy_utils::visitors::is_local_used;
 use clippy_utils::{path_to_local_id, paths, peel_blocks, peel_ref_operators, strip_pat_refs};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
-use rustc_hir::{BinOpKind, Expr, ExprKind, PatKind};
+use rustc_hir::{BinOpKind, Closure, Expr, ExprKind, PatKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::{self, UintTy};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -51,7 +51,7 @@ impl<'tcx> LateLintPass<'tcx> for ByteCount {
             if count.ident.name == sym::count;
             if let ExprKind::MethodCall(filter, [filter_recv, filter_arg], _) = count_recv.kind;
             if filter.ident.name == sym!(filter);
-            if let ExprKind::Closure { body, .. } = filter_arg.kind;
+            if let ExprKind::Closure(&Closure { body, .. }) = filter_arg.kind;
             let body = cx.tcx.hir().body(body);
             if let [param] = body.params;
             if let PatKind::Binding(_, arg_id, _, _) = strip_pat_refs(param.pat).kind;
diff --git a/src/tools/clippy/clippy_lints/src/eta_reduction.rs b/src/tools/clippy/clippy_lints/src/eta_reduction.rs
index 42fac550ec69c..80c84014bfdeb 100644
--- a/src/tools/clippy/clippy_lints/src/eta_reduction.rs
+++ b/src/tools/clippy/clippy_lints/src/eta_reduction.rs
@@ -7,7 +7,7 @@ use clippy_utils::{higher, is_adjusted, path_to_local, path_to_local_id};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::def_id::DefId;
-use rustc_hir::{Expr, ExprKind, Param, PatKind, Unsafety};
+use rustc_hir::{Closure, Expr, ExprKind, Param, PatKind, Unsafety};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
 use rustc_middle::ty::binding::BindingMode;
@@ -78,7 +78,7 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction {
             return;
         }
         let body = match expr.kind {
-            ExprKind::Closure { body, .. } => cx.tcx.hir().body(body),
+            ExprKind::Closure(&Closure { body, .. }) => cx.tcx.hir().body(body),
             _ => return,
         };
         if body.value.span.from_expansion() {
diff --git a/src/tools/clippy/clippy_lints/src/infinite_iter.rs b/src/tools/clippy/clippy_lints/src/infinite_iter.rs
index 78b5ec8ec1ef4..01c7eef4e04da 100644
--- a/src/tools/clippy/clippy_lints/src/infinite_iter.rs
+++ b/src/tools/clippy/clippy_lints/src/infinite_iter.rs
@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::span_lint;
 use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
 use clippy_utils::{higher, match_def_path, path_def_id, paths};
-use rustc_hir::{BorrowKind, Expr, ExprKind};
+use rustc_hir::{BorrowKind, Closure, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::{sym, Symbol};
@@ -159,7 +159,7 @@ fn is_infinite(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
                 }
             }
             if method.ident.name == sym!(flat_map) && args.len() == 2 {
-                if let ExprKind::Closure { body, .. } = args[1].kind {
+                if let ExprKind::Closure(&Closure { body, .. }) = args[1].kind {
                     let body = cx.tcx.hir().body(body);
                     return is_infinite(cx, &body.value);
                 }
diff --git a/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs b/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
index 0b6d9adb553e4..a7ef562b21fc4 100644
--- a/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
@@ -9,7 +9,7 @@ use rustc_ast::ast;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::{walk_expr, Visitor};
-use rustc_hir::{BinOpKind, BorrowKind, Expr, ExprKind, HirId, Mutability, Pat, PatKind, QPath};
+use rustc_hir::{BinOpKind, BorrowKind, Closure, Expr, ExprKind, HirId, Mutability, Pat, PatKind, QPath};
 use rustc_lint::LateContext;
 use rustc_middle::middle::region;
 use rustc_middle::ty::{self, Ty};
@@ -369,7 +369,7 @@ impl<'a, 'tcx> Visitor<'tcx> for VarVisitor<'a, 'tcx> {
                     self.visit_expr(expr);
                 }
             },
-            ExprKind::Closure { body, .. } => {
+            ExprKind::Closure(&Closure { body, .. }) => {
                 let body = self.cx.tcx.hir().body(body);
                 self.visit_expr(&body.value);
             },
diff --git a/src/tools/clippy/clippy_lints/src/loops/while_let_on_iterator.rs b/src/tools/clippy/clippy_lints/src/loops/while_let_on_iterator.rs
index a57159750664f..b94bbd2bd417d 100644
--- a/src/tools/clippy/clippy_lints/src/loops/while_let_on_iterator.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/while_let_on_iterator.rs
@@ -8,7 +8,7 @@ use clippy_utils::{
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_expr, Visitor};
-use rustc_hir::{def::Res, Expr, ExprKind, HirId, Local, Mutability, PatKind, QPath, UnOp};
+use rustc_hir::{Closure, def::Res, Expr, ExprKind, HirId, Local, Mutability, PatKind, QPath, UnOp};
 use rustc_lint::LateContext;
 use rustc_middle::ty::adjustment::Adjust;
 use rustc_span::{symbol::sym, Symbol};
@@ -220,7 +220,7 @@ fn uses_iter<'tcx>(cx: &LateContext<'tcx>, iter_expr: &IterExpr, container: &'tc
                 if let Some(e) = e {
                     self.visit_expr(e);
                 }
-            } else if let ExprKind::Closure { body: id, .. } = e.kind {
+            } else if let ExprKind::Closure(&Closure { body: id, .. }) = e.kind {
                 if is_res_used(self.cx, self.iter_expr.path, id) {
                     self.uses_iter = true;
                 }
@@ -260,7 +260,7 @@ fn needs_mutable_borrow(cx: &LateContext<'_>, iter_expr: &IterExpr, loop_expr: &
                     if let Some(e) = e {
                         self.visit_expr(e);
                     }
-                } else if let ExprKind::Closure { body: id, .. } = e.kind {
+                } else if let ExprKind::Closure(&Closure { body: id, .. }) = e.kind {
                     self.used_iter = is_res_used(self.cx, self.iter_expr.path, id);
                 } else {
                     walk_expr(self, e);
@@ -307,7 +307,7 @@ fn needs_mutable_borrow(cx: &LateContext<'_>, iter_expr: &IterExpr, loop_expr: &
                     if let Some(e) = e {
                         self.visit_expr(e);
                     }
-                } else if let ExprKind::Closure { body: id, .. } = e.kind {
+                } else if let ExprKind::Closure(&Closure { body: id, .. }) = e.kind {
                     self.used_after = is_res_used(self.cx, self.iter_expr.path, id);
                 } else {
                     walk_expr(self, e);
diff --git a/src/tools/clippy/clippy_lints/src/manual_async_fn.rs b/src/tools/clippy/clippy_lints/src/manual_async_fn.rs
index d7d8a59215280..93a34f452f6d6 100644
--- a/src/tools/clippy/clippy_lints/src/manual_async_fn.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_async_fn.rs
@@ -6,7 +6,7 @@ use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{
-    AsyncGeneratorKind, Block, Body, Expr, ExprKind, FnDecl, FnRetTy, GeneratorKind, GenericArg, GenericBound, HirId,
+    AsyncGeneratorKind, Block, Body, Closure, Expr, ExprKind, FnDecl, FnRetTy, GeneratorKind, GenericArg, GenericBound, HirId,
     IsAsync, ItemKind, LifetimeName, Term, TraitRef, Ty, TyKind, TypeBindingKind,
 };
 use rustc_lint::{LateContext, LateLintPass};
@@ -177,7 +177,7 @@ fn desugared_async_block<'tcx>(cx: &LateContext<'tcx>, block: &'tcx Block<'tcx>)
         if let Some(block_expr) = block.expr;
         if let Some(args) = match_function_call(cx, block_expr, &FUTURE_FROM_GENERATOR);
         if args.len() == 1;
-        if let Expr{kind: ExprKind::Closure { body, .. }, ..} = args[0];
+        if let Expr{kind: ExprKind::Closure(&Closure { body, .. }), ..} = args[0];
         let closure_body = cx.tcx.hir().body(body);
         if closure_body.generator_kind == Some(GeneratorKind::Async(AsyncGeneratorKind::Block));
         then {
diff --git a/src/tools/clippy/clippy_lints/src/manual_ok_or.rs b/src/tools/clippy/clippy_lints/src/manual_ok_or.rs
index 18cfd00376784..9abf2507b921c 100644
--- a/src/tools/clippy/clippy_lints/src/manual_ok_or.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_ok_or.rs
@@ -5,7 +5,7 @@ use clippy_utils::{is_lang_ctor, path_to_local_id};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::{ResultErr, ResultOk};
-use rustc_hir::{Expr, ExprKind, PatKind};
+use rustc_hir::{Closure, Expr, ExprKind, PatKind};
 use rustc_lint::LintContext;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::lint::in_external_macro;
@@ -88,7 +88,7 @@ fn is_ok_wrapping(cx: &LateContext<'_>, map_expr: &Expr<'_>) -> bool {
         }
     }
     if_chain! {
-        if let ExprKind::Closure { body, .. } = map_expr.kind;
+        if let ExprKind::Closure(&Closure { body, .. }) = map_expr.kind;
         let body = cx.tcx.hir().body(body);
         if let PatKind::Binding(_, param_id, ..) = body.params[0].pat.kind;
         if let ExprKind::Call(Expr { kind: ExprKind::Path(ok_path), .. }, &[ref ok_arg]) = body.value.kind;
diff --git a/src/tools/clippy/clippy_lints/src/manual_retain.rs b/src/tools/clippy/clippy_lints/src/manual_retain.rs
index c35e1e021ef1c..42d2577cc3161 100644
--- a/src/tools/clippy/clippy_lints/src/manual_retain.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_retain.rs
@@ -148,7 +148,7 @@ fn check_to_owned(
 
 fn suggest(cx: &LateContext<'_>, parent_expr: &hir::Expr<'_>, left_expr: &hir::Expr<'_>, filter_expr: &hir::Expr<'_>) {
     if let hir::ExprKind::MethodCall(_, [_, closure], _) = filter_expr.kind
-        && let hir::ExprKind::Closure{ body, ..} = closure.kind
+        && let hir::ExprKind::Closure(&hir::Closure { body, ..}) = closure.kind
         && let filter_body = cx.tcx.hir().body(body)
         && let [filter_params] = filter_body.params
         && let Some(sugg) = match filter_params.pat.kind {
diff --git a/src/tools/clippy/clippy_lints/src/map_clone.rs b/src/tools/clippy/clippy_lints/src/map_clone.rs
index 3533de54a1e3d..95c312f1fe26b 100644
--- a/src/tools/clippy/clippy_lints/src/map_clone.rs
+++ b/src/tools/clippy/clippy_lints/src/map_clone.rs
@@ -67,7 +67,7 @@ impl<'tcx> LateLintPass<'tcx> for MapClone {
             if method.ident.name == sym::map;
             let ty = cx.typeck_results().expr_ty(&args[0]);
             if is_type_diagnostic_item(cx, ty, sym::Option) || is_trait_method(cx, e, sym::Iterator);
-            if let hir::ExprKind::Closure { body, .. } = args[1].kind;
+            if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = args[1].kind;
             then {
                 let closure_body = cx.tcx.hir().body(body);
                 let closure_expr = peel_blocks(&closure_body.value);
diff --git a/src/tools/clippy/clippy_lints/src/map_err_ignore.rs b/src/tools/clippy/clippy_lints/src/map_err_ignore.rs
index 0c22144104872..21d0e19eb0a48 100644
--- a/src/tools/clippy/clippy_lints/src/map_err_ignore.rs
+++ b/src/tools/clippy/clippy_lints/src/map_err_ignore.rs
@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use rustc_hir::{CaptureBy, Expr, ExprKind, PatKind};
+use rustc_hir::{CaptureBy, Closure, Expr, ExprKind, PatKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
@@ -119,12 +119,12 @@ impl<'tcx> LateLintPass<'tcx> for MapErrIgnore {
             if method.ident.as_str() == "map_err" && args.len() == 2 {
                 // make sure the first argument is a closure, and grab the CaptureRef, BodyId, and fn_decl_span
                 // fields
-                if let ExprKind::Closure {
+                if let ExprKind::Closure(&Closure {
                     capture_clause,
                     body,
                     fn_decl_span,
                     ..
-                } = args[1].kind
+                }) = args[1].kind
                 {
                     // check if this is by Reference (meaning there's no move statement)
                     if capture_clause == CaptureBy::Ref {
diff --git a/src/tools/clippy/clippy_lints/src/map_unit_fn.rs b/src/tools/clippy/clippy_lints/src/map_unit_fn.rs
index 663246b4c8622..af9d948af00e6 100644
--- a/src/tools/clippy/clippy_lints/src/map_unit_fn.rs
+++ b/src/tools/clippy/clippy_lints/src/map_unit_fn.rs
@@ -169,7 +169,7 @@ fn unit_closure<'tcx>(
     expr: &hir::Expr<'_>,
 ) -> Option<(&'tcx hir::Param<'tcx>, &'tcx hir::Expr<'tcx>)> {
     if_chain! {
-        if let hir::ExprKind::Closure { fn_decl, body, .. } = expr.kind;
+        if let hir::ExprKind::Closure(&hir::Closure { fn_decl, body, .. }) = expr.kind;
         let body = cx.tcx.hir().body(body);
         let body_expr = &body.value;
         if fn_decl.inputs.len() == 1;
diff --git a/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs b/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs
index d31b736982b34..2f117e4dcc374 100644
--- a/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs
@@ -150,7 +150,7 @@ pub(crate) trait BindInsteadOfMap {
         }
 
         match arg.kind {
-            hir::ExprKind::Closure { body, fn_decl_span, .. } => {
+            hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, .. }) => {
                 let closure_body = cx.tcx.hir().body(body);
                 let closure_expr = peel_blocks(&closure_body.value);
 
diff --git a/src/tools/clippy/clippy_lints/src/methods/filter_map.rs b/src/tools/clippy/clippy_lints/src/methods/filter_map.rs
index 58c3e52e138c4..7dbfd95c50db4 100644
--- a/src/tools/clippy/clippy_lints/src/methods/filter_map.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/filter_map.rs
@@ -6,7 +6,7 @@ use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::def::Res;
-use rustc_hir::{Expr, ExprKind, PatKind, PathSegment, QPath, UnOp};
+use rustc_hir::{Closure, Expr, ExprKind, PatKind, PathSegment, QPath, UnOp};
 use rustc_lint::LateContext;
 use rustc_span::source_map::Span;
 use rustc_span::symbol::{sym, Symbol};
@@ -22,8 +22,8 @@ fn is_method<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, method_name: Sy
         hir::ExprKind::Path(QPath::Resolved(_, segments)) => {
             segments.segments.last().unwrap().ident.name == method_name
         },
-        hir::ExprKind::Closure { body, .. } => {
-            let body = cx.tcx.hir().body(*body);
+        hir::ExprKind::Closure(&hir::Closure { body, .. }) => {
+            let body = cx.tcx.hir().body(body);
             let closure_expr = peel_blocks(&body.value);
             let arg_id = body.params[0].pat.hir_id;
             match closure_expr.kind {
@@ -106,7 +106,7 @@ pub(super) fn check<'tcx>(
             if is_trait_method(cx, map_recv, sym::Iterator);
 
             // filter(|x| ...is_some())...
-            if let ExprKind::Closure { body: filter_body_id, .. } = filter_arg.kind;
+            if let ExprKind::Closure(&Closure { body: filter_body_id, .. }) = filter_arg.kind;
             let filter_body = cx.tcx.hir().body(filter_body_id);
             if let [filter_param] = filter_body.params;
             // optional ref pattern: `filter(|&x| ..)`
@@ -129,7 +129,7 @@ pub(super) fn check<'tcx>(
             if path.ident.name.as_str() == if is_result { "is_ok" } else { "is_some" };
 
             // ...map(|x| ...unwrap())
-            if let ExprKind::Closure { body: map_body_id, .. } = map_arg.kind;
+            if let ExprKind::Closure(&Closure { body: map_body_id, .. }) = map_arg.kind;
             let map_body = cx.tcx.hir().body(map_body_id);
             if let [map_param] = map_body.params;
             if let PatKind::Binding(_, map_param_id, map_param_ident, None) = map_param.pat.kind;
diff --git a/src/tools/clippy/clippy_lints/src/methods/option_as_ref_deref.rs b/src/tools/clippy/clippy_lints/src/methods/option_as_ref_deref.rs
index 912499bf96b94..20cad0f181e95 100644
--- a/src/tools/clippy/clippy_lints/src/methods/option_as_ref_deref.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/option_as_ref_deref.rs
@@ -51,7 +51,7 @@ pub(super) fn check<'tcx>(
             .map_or(false, |fun_def_id| {
                 deref_aliases.iter().any(|path| match_def_path(cx, fun_def_id, path))
             }),
-        hir::ExprKind::Closure { body, .. } => {
+        hir::ExprKind::Closure(&hir::Closure { body, .. }) => {
             let closure_body = cx.tcx.hir().body(body);
             let closure_expr = peel_blocks(&closure_body.value);
 
diff --git a/src/tools/clippy/clippy_lints/src/methods/option_map_or_none.rs b/src/tools/clippy/clippy_lints/src/methods/option_map_or_none.rs
index 2d71bd6f240fc..5a39b82b027d1 100644
--- a/src/tools/clippy/clippy_lints/src/methods/option_map_or_none.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/option_map_or_none.rs
@@ -71,7 +71,7 @@ pub(super) fn check<'tcx>(
     if is_option {
         let self_snippet = snippet(cx, recv.span, "..");
         if_chain! {
-            if let hir::ExprKind::Closure { body, fn_decl_span, .. } = map_arg.kind;
+            if let hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, .. }) = map_arg.kind;
             let arg_snippet = snippet(cx, fn_decl_span, "..");
             let body = cx.tcx.hir().body(body);
             if let Some((func, [arg_char])) = reduce_unit_expression(&body.value);
diff --git a/src/tools/clippy/clippy_lints/src/methods/search_is_some.rs b/src/tools/clippy/clippy_lints/src/methods/search_is_some.rs
index b11f4531a912c..7572ba3fe9a94 100644
--- a/src/tools/clippy/clippy_lints/src/methods/search_is_some.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/search_is_some.rs
@@ -41,7 +41,7 @@ pub(super) fn check<'tcx>(
             let mut applicability = Applicability::MachineApplicable;
             let any_search_snippet = if_chain! {
                 if search_method == "find";
-                if let hir::ExprKind::Closure { body, .. } = search_arg.kind;
+                if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = search_arg.kind;
                 let closure_body = cx.tcx.hir().body(body);
                 if let Some(closure_arg) = closure_body.params.get(0);
                 then {
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs
index a405467f5e8af..bafa6fc584d48 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs
@@ -18,7 +18,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr<
         return;
     }
 
-    if let hir::ExprKind::Closure { body, .. } = arg.kind {
+    if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = arg.kind {
         let body = cx.tcx.hir().body(body);
         let arg_id = body.params[0].pat.hir_id;
         let mutates_arg =
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_fold.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_fold.rs
index 913c4dbedc301..c3531d4d0511e 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_fold.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_fold.rs
@@ -29,7 +29,7 @@ pub(super) fn check(
     ) {
         if_chain! {
             // Extract the body of the closure passed to fold
-            if let hir::ExprKind::Closure { body, .. } = acc.kind;
+            if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = acc.kind;
             let closure_body = cx.tcx.hir().body(body);
             let closure_expr = peel_blocks(&closure_body.value);
 
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_lazy_eval.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_lazy_eval.rs
index 865f6d0318eb9..21767d74c87b8 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_lazy_eval.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_lazy_eval.rs
@@ -22,7 +22,7 @@ pub(super) fn check<'tcx>(
     let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(recv), sym::Result);
 
     if is_option || is_result {
-        if let hir::ExprKind::Closure { body, .. } = arg.kind {
+        if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = arg.kind {
             let body = cx.tcx.hir().body(body);
             let body_expr = &body.value;
 
diff --git a/src/tools/clippy/clippy_lints/src/needless_for_each.rs b/src/tools/clippy/clippy_lints/src/needless_for_each.rs
index 48ac695f2acfb..10e188ecb79a6 100644
--- a/src/tools/clippy/clippy_lints/src/needless_for_each.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_for_each.rs
@@ -1,7 +1,7 @@
 use rustc_errors::Applicability;
 use rustc_hir::{
     intravisit::{walk_expr, Visitor},
-    Expr, ExprKind, Stmt, StmtKind,
+    Closure, Expr, ExprKind, Stmt, StmtKind,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -72,7 +72,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessForEach {
             if has_iter_method(cx, cx.typeck_results().expr_ty(iter_recv)).is_some();
             // Skip the lint if the body is not block because this is simpler than `for` loop.
             // e.g. `v.iter().for_each(f)` is simpler and clearer than using `for` loop.
-            if let ExprKind::Closure { body, .. } = for_each_arg.kind;
+            if let ExprKind::Closure(&Closure { body, .. }) = for_each_arg.kind;
             let body = cx.tcx.hir().body(body);
             if let ExprKind::Block(..) = body.value.kind;
             then {
diff --git a/src/tools/clippy/clippy_lints/src/only_used_in_recursion.rs b/src/tools/clippy/clippy_lints/src/only_used_in_recursion.rs
index 677ac998b5682..d461668077e0a 100644
--- a/src/tools/clippy/clippy_lints/src/only_used_in_recursion.rs
+++ b/src/tools/clippy/clippy_lints/src/only_used_in_recursion.rs
@@ -11,7 +11,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData};
 use rustc_hir::intravisit::{walk_expr, walk_stmt, FnKind, Visitor};
 use rustc_hir::{
-    Arm, Block, Body, Expr, ExprKind, Guard, HirId, ImplicitSelfKind, Let, Local, Pat, PatKind, Path, PathSegment,
+    Arm, Closure, Block, Body, Expr, ExprKind, Guard, HirId, ImplicitSelfKind, Let, Local, Pat, PatKind, Path, PathSegment,
     QPath, Stmt, StmtKind, TyKind, UnOp,
 };
 use rustc_lint::{LateContext, LateLintPass};
@@ -298,7 +298,7 @@ impl<'tcx> Visitor<'tcx> for SideEffectVisit<'tcx> {
             },
             ExprKind::Match(expr, arms, _) => self.visit_match(expr, arms),
             // since analysing the closure is not easy, just set all variables in it to side-effect
-            ExprKind::Closure { body, .. } => {
+            ExprKind::Closure(&Closure { body, .. }) => {
                 let body = self.tcx.hir().body(body);
                 self.visit_body(body);
                 let vars = std::mem::take(&mut self.ret_vars);
diff --git a/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs b/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs
index 65ed798867d19..f5a93cebab8ca 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs
@@ -69,7 +69,7 @@ impl EarlyLintPass for RedundantClosureCall {
         if_chain! {
             if let ast::ExprKind::Call(ref paren, _) = expr.kind;
             if let ast::ExprKind::Paren(ref closure) = paren.kind;
-            if let ast::ExprKind::Closure(_, _, _, ref decl, ref block, _) = closure.kind;
+            if let ast::ExprKind::Closure(_, _, _, _, ref decl, ref block, _) = closure.kind;
             then {
                 let mut visitor = ReturnVisitor::new();
                 visitor.visit_expr(block);
diff --git a/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs b/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs
index c4c1aa11004ac..fe8859905953f 100644
--- a/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs
+++ b/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs
@@ -582,7 +582,7 @@ fn ident_difference_expr_with_base_location(
         | (Await(_), Await(_))
         | (Async(_, _, _), Async(_, _, _))
         | (Block(_, _), Block(_, _))
-        | (Closure(_, _, _, _, _, _), Closure(_, _, _, _, _, _))
+        | (Closure(_, _, _, _, _, _, _), Closure(_, _, _, _, _, _, _))
         | (Match(_, _), Match(_, _))
         | (Loop(_, _), Loop(_, _))
         | (ForLoop(_, _, _, _), ForLoop(_, _, _, _))
diff --git a/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs b/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs
index f58da7ce9b420..b0fce91abeb7d 100644
--- a/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs
+++ b/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs
@@ -2,7 +2,7 @@ use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
 use clippy_utils::{get_trait_def_id, paths};
 use if_chain::if_chain;
 use rustc_hir::def_id::DefId;
-use rustc_hir::{Expr, ExprKind, StmtKind};
+use rustc_hir::{Closure, Expr, ExprKind, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
 use rustc_middle::ty::{GenericPredicates, PredicateKind, ProjectionPredicate, TraitPredicate};
@@ -116,7 +116,7 @@ fn get_args_to_check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> Ve
 
 fn check_arg<'tcx>(cx: &LateContext<'tcx>, arg: &'tcx Expr<'tcx>) -> Option<(Span, Option<Span>)> {
     if_chain! {
-        if let ExprKind::Closure { body, fn_decl_span, .. } = arg.kind;
+        if let ExprKind::Closure(&Closure { body, fn_decl_span, .. }) = arg.kind;
         if let ty::Closure(_def_id, substs) = &cx.typeck_results().node_type(arg.hir_id).kind();
         let ret_ty = substs.as_closure().sig().output();
         let ty = cx.tcx.erase_late_bound_regions(ret_ty);
diff --git a/src/tools/clippy/clippy_lints/src/unnecessary_sort_by.rs b/src/tools/clippy/clippy_lints/src/unnecessary_sort_by.rs
index 7d4373b2a57bc..ea5aadbbca1c6 100644
--- a/src/tools/clippy/clippy_lints/src/unnecessary_sort_by.rs
+++ b/src/tools/clippy/clippy_lints/src/unnecessary_sort_by.rs
@@ -3,7 +3,7 @@ use clippy_utils::sugg::Sugg;
 use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind, Mutability, Param, Pat, PatKind, Path, PathSegment, QPath};
+use rustc_hir::{Closure, Expr, ExprKind, Mutability, Param, Pat, PatKind, Path, PathSegment, QPath};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::{self, subst::GenericArgKind};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -155,7 +155,7 @@ fn detect_lint(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<LintTrigger> {
         if let ExprKind::MethodCall(name_ident, args, _) = &expr.kind;
         if let name = name_ident.ident.name.to_ident_string();
         if name == "sort_by" || name == "sort_unstable_by";
-        if let [vec, Expr { kind: ExprKind::Closure{ body: closure_body_id, .. }, .. }] = args;
+        if let [vec, Expr { kind: ExprKind::Closure(Closure { body: closure_body_id, .. }), .. }] = args;
         if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(vec), sym::Vec);
         if let closure_body = cx.tcx.hir().body(*closure_body_id);
         if let &[
diff --git a/src/tools/clippy/clippy_lints/src/utils/author.rs b/src/tools/clippy/clippy_lints/src/utils/author.rs
index 2c8820eb7e1a1..bbb04c9945a09 100644
--- a/src/tools/clippy/clippy_lints/src/utils/author.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/author.rs
@@ -6,7 +6,7 @@ use rustc_ast::ast::{LitFloatType, LitKind};
 use rustc_ast::LitIntType;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir as hir;
-use rustc_hir::{ArrayLen, ExprKind, FnRetTy, HirId, Lit, PatKind, QPath, StmtKind, TyKind};
+use rustc_hir::{ArrayLen, Closure, ExprKind, FnRetTy, HirId, Lit, PatKind, QPath, StmtKind, TyKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::{Ident, Symbol};
@@ -466,13 +466,13 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
                 self.expr(scrutinee);
                 self.slice(arms, |arm| self.arm(arm));
             },
-            ExprKind::Closure {
+            ExprKind::Closure(&Closure {
                 capture_clause,
                 fn_decl,
                 body: body_id,
                 movability,
                 ..
-            } => {
+            }) => {
                 let movability = OptionPat::new(movability.map(|m| format!("Movability::{m:?}")));
 
                 let ret_ty = match fn_decl.output {
diff --git a/src/tools/clippy/clippy_utils/src/ast_utils.rs b/src/tools/clippy/clippy_utils/src/ast_utils.rs
index 177e754ee091e..431b09d53c33b 100644
--- a/src/tools/clippy/clippy_utils/src/ast_utils.rs
+++ b/src/tools/clippy/clippy_utils/src/ast_utils.rs
@@ -168,8 +168,8 @@ pub fn eq_expr(l: &Expr, r: &Expr) -> bool {
         (AssignOp(lo, lp, lv), AssignOp(ro, rp, rv)) => lo.node == ro.node && eq_expr(lp, rp) && eq_expr(lv, rv),
         (Field(lp, lf), Field(rp, rf)) => eq_id(*lf, *rf) && eq_expr(lp, rp),
         (Match(ls, la), Match(rs, ra)) => eq_expr(ls, rs) && over(la, ra, eq_arm),
-        (Closure(lc, la, lm, lf, lb, _), Closure(rc, ra, rm, rf, rb, _)) => {
-            lc == rc && la.is_async() == ra.is_async() && lm == rm && eq_fn_decl(lf, rf) && eq_expr(lb, rb)
+        (Closure(lb, lc, la, lm, lf, le, _), Closure(rb, rc, ra, rm, rf, re, _)) => {
+            eq_closure_binder(lb, rb) && lc == rc && la.is_async() == ra.is_async() && lm == rm && eq_fn_decl(lf, rf) && eq_expr(le, re)
         },
         (Async(lc, _, lb), Async(rc, _, rb)) => lc == rc && eq_block(lb, rb),
         (Range(lf, lt, ll), Range(rf, rt, rl)) => ll == rl && eq_expr_opt(lf, rf) && eq_expr_opt(lt, rt),
@@ -561,6 +561,15 @@ pub fn eq_fn_decl(l: &FnDecl, r: &FnDecl) -> bool {
         })
 }
 
+pub fn eq_closure_binder(l: &ClosureBinder, r: &ClosureBinder) -> bool {
+    match (l, r) {
+        (ClosureBinder::NotPresent, ClosureBinder::NotPresent) => true,
+        (ClosureBinder::For { generic_params: lp, .. }, ClosureBinder::For { generic_params: rp, .. }) => 
+            lp.len() == rp.len() && std::iter::zip(lp.iter(), rp.iter()).all(|(l, r)| eq_generic_param(l, r)),
+        _ => false,
+    }
+}
+
 pub fn eq_fn_ret_ty(l: &FnRetTy, r: &FnRetTy) -> bool {
     match (l, r) {
         (FnRetTy::Default(_), FnRetTy::Default(_)) => true,
diff --git a/src/tools/clippy/clippy_utils/src/hir_utils.rs b/src/tools/clippy/clippy_utils/src/hir_utils.rs
index 793e3cc58c21d..4e5c3850f86a7 100644
--- a/src/tools/clippy/clippy_utils/src/hir_utils.rs
+++ b/src/tools/clippy/clippy_utils/src/hir_utils.rs
@@ -6,7 +6,7 @@ use rustc_data_structures::fx::FxHasher;
 use rustc_hir::def::Res;
 use rustc_hir::HirIdMap;
 use rustc_hir::{
-    ArrayLen, BinOpKind, Block, BodyId, Expr, ExprField, ExprKind, FnRetTy, GenericArg, GenericArgs, Guard, HirId,
+    ArrayLen, BinOpKind, Closure, Block, BodyId, Expr, ExprField, ExprKind, FnRetTy, GenericArg, GenericArgs, Guard, HirId,
     InlineAsmOperand, Let, Lifetime, LifetimeName, ParamName, Pat, PatField, PatKind, Path, PathSegment, QPath, Stmt,
     StmtKind, Ty, TyKind, TypeBinding,
 };
@@ -662,9 +662,9 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                 self.hash_expr(e);
                 self.hash_ty(ty);
             },
-            ExprKind::Closure {
+            ExprKind::Closure(&Closure {
                 capture_clause, body, ..
-            } => {
+            }) => {
                 std::mem::discriminant(&capture_clause).hash(&mut self.s);
                 // closures inherit TypeckResults
                 self.hash_expr(&self.cx.tcx.hir().body(body).value);
diff --git a/src/tools/clippy/clippy_utils/src/lib.rs b/src/tools/clippy/clippy_utils/src/lib.rs
index 1b32f0aaeb8df..242d4315378e3 100644
--- a/src/tools/clippy/clippy_utils/src/lib.rs
+++ b/src/tools/clippy/clippy_utils/src/lib.rs
@@ -79,10 +79,10 @@ use rustc_hir::hir_id::{HirIdMap, HirIdSet};
 use rustc_hir::intravisit::{walk_expr, FnKind, Visitor};
 use rustc_hir::LangItem::{OptionNone, ResultErr, ResultOk};
 use rustc_hir::{
-    def, Arm, ArrayLen, BindingAnnotation, Block, BlockCheckMode, Body, Constness, Destination, Expr, ExprKind, FnDecl,
-    HirId, Impl, ImplItem, ImplItemKind, IsAsync, Item, ItemKind, LangItem, Local, MatchSource, Mutability, Node,
-    Param, Pat, PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitRef, TyKind,
-    UnOp,
+    def, Arm, ArrayLen, BindingAnnotation, Block, BlockCheckMode, Body, Closure, Constness, Destination, Expr,
+    ExprKind, FnDecl, HirId, Impl, ImplItem, ImplItemKind, IsAsync, Item, ItemKind, LangItem, Local, MatchSource,
+    Mutability, Node, Param, Pat, PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind, TraitItem, TraitItemKind,
+    TraitRef, TyKind, UnOp,
 };
 use rustc_lint::{LateContext, Level, Lint, LintContext};
 use rustc_middle::hir::place::PlaceBase;
@@ -1699,7 +1699,7 @@ pub fn get_async_fn_body<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'_>) -> Option<&'t
         _,
         &[
             Expr {
-                kind: ExprKind::Closure { body, .. },
+                kind: ExprKind::Closure(&Closure { body, .. }),
                 ..
             },
         ],
@@ -1786,7 +1786,7 @@ pub fn is_expr_identity_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool
     }
 
     match expr.kind {
-        ExprKind::Closure { body, .. } => is_body_identity_function(cx, cx.tcx.hir().body(body)),
+        ExprKind::Closure(&Closure { body, .. }) => is_body_identity_function(cx, cx.tcx.hir().body(body)),
         _ => path_def_id(cx, expr).map_or(false, |id| match_def_path(cx, id, &paths::CONVERT_IDENTITY)),
     }
 }
diff --git a/src/tools/clippy/clippy_utils/src/sugg.rs b/src/tools/clippy/clippy_utils/src/sugg.rs
index aa119539b1b39..4326a103d44b7 100644
--- a/src/tools/clippy/clippy_utils/src/sugg.rs
+++ b/src/tools/clippy/clippy_utils/src/sugg.rs
@@ -8,7 +8,7 @@ use rustc_ast::{ast, token};
 use rustc_ast_pretty::pprust::token_kind_to_string;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
-use rustc_hir::{ExprKind, HirId, MutTy, TyKind};
+use rustc_hir::{Closure, ExprKind, HirId, MutTy, TyKind};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::{EarlyContext, LateContext, LintContext};
 use rustc_middle::hir::place::ProjectionKind;
@@ -790,7 +790,7 @@ pub struct DerefClosure {
 ///
 /// note: this only works on single line immutable closures with exactly one input parameter.
 pub fn deref_closure_args<'tcx>(cx: &LateContext<'_>, closure: &'tcx hir::Expr<'_>) -> Option<DerefClosure> {
-    if let hir::ExprKind::Closure { fn_decl, body, .. } = closure.kind {
+    if let hir::ExprKind::Closure(&Closure { fn_decl, body, .. }) = closure.kind {
         let closure_body = cx.tcx.hir().body(body);
         // is closure arg a type annotated double reference (i.e.: `|x: &&i32| ...`)
         // a type annotation is present if param `kind` is different from `TyKind::Infer`