turn hir::ItemKind::Fn into a named-field variant

38 files changed, 104 insertions, 81 deletions

diff --git a/compiler/rustc_ast_lowering/src/item.rs b/compiler/rustc_ast_lowering/src/item.rs
index 2cf6a2a909b..74a02eebd02 100644
--- a/compiler/rustc_ast_lowering/src/item.rs
+++ b/compiler/rustc_ast_lowering/src/item.rs
@@ -233,7 +233,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         header: this.lower_fn_header(*header, hir::Safety::Safe),
                         span: this.lower_span(*fn_sig_span),
                     };
-                    hir::ItemKind::Fn(sig, generics, body_id)
+                    hir::ItemKind::Fn { sig, generics, body: body_id }
                 })
             }
             ItemKind::Mod(_, mod_kind) => match mod_kind {
@@ -435,11 +435,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
             }
             ItemKind::Delegation(box delegation) => {
                 let delegation_results = self.lower_delegation(delegation, id);
-                hir::ItemKind::Fn(
-                    delegation_results.sig,
-                    delegation_results.generics,
-                    delegation_results.body_id,
-                )
+                hir::ItemKind::Fn {
+                    sig: delegation_results.sig,
+                    generics: delegation_results.generics,
+                    body: delegation_results.body_id,
+                }
             }
             ItemKind::MacCall(..) | ItemKind::DelegationMac(..) => {
                 panic!("macros should have been expanded by now")
diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index c690789b587..16de160cae5 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -981,7 +981,9 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
 
             let arg = match hir.get_if_local(callee_def_id) {
                 Some(
-                    hir::Node::Item(hir::Item { ident, kind: hir::ItemKind::Fn(sig, ..), .. })
+                    hir::Node::Item(hir::Item {
+                        ident, kind: hir::ItemKind::Fn { sig, .. }, ..
+                    })
                     | hir::Node::TraitItem(hir::TraitItem {
                         ident,
                         kind: hir::TraitItemKind::Fn(sig, _),
@@ -1020,7 +1022,9 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             // ...otherwise we are probably in the tail expression of the function, point at the
             // return type.
             match self.infcx.tcx.hir_node_by_def_id(hir.get_parent_item(fn_call_id).def_id) {
-                hir::Node::Item(hir::Item { ident, kind: hir::ItemKind::Fn(sig, ..), .. })
+                hir::Node::Item(hir::Item {
+                    ident, kind: hir::ItemKind::Fn { sig, .. }, ..
+                })
                 | hir::Node::TraitItem(hir::TraitItem {
                     ident,
                     kind: hir::TraitItemKind::Fn(sig, _),
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index 7a3cde4bc2f..c09f4e9fadc 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -3640,7 +3640,7 @@ impl<'hir> Item<'hir> {
             ItemKind::Const(ty, generics, body), (ty, generics, *body);
 
         expect_fn, (&FnSig<'hir>, &'hir Generics<'hir>, BodyId),
-            ItemKind::Fn(sig, generics, body), (sig, generics, *body);
+            ItemKind::Fn { sig, generics, body }, (sig, generics, *body);
 
         expect_macro, (&ast::MacroDef, MacroKind), ItemKind::Macro(def, mk), (def, *mk);
 
@@ -3768,7 +3768,7 @@ pub enum ItemKind<'hir> {
     /// A `const` item.
     Const(&'hir Ty<'hir>, &'hir Generics<'hir>, BodyId),
     /// A function declaration.
-    Fn(FnSig<'hir>, &'hir Generics<'hir>, BodyId),
+    Fn { sig: FnSig<'hir>, generics: &'hir Generics<'hir>, body: BodyId },
     /// A MBE macro definition (`macro_rules!` or `macro`).
     Macro(&'hir ast::MacroDef, MacroKind),
     /// A module.
@@ -3819,7 +3819,7 @@ pub struct Impl<'hir> {
 impl ItemKind<'_> {
     pub fn generics(&self) -> Option<&Generics<'_>> {
         Some(match *self {
-            ItemKind::Fn(_, ref generics, _)
+            ItemKind::Fn { ref generics, .. }
             | ItemKind::TyAlias(_, ref generics)
             | ItemKind::Const(_, ref generics, _)
             | ItemKind::Enum(_, ref generics)
@@ -3838,7 +3838,7 @@ impl ItemKind<'_> {
             ItemKind::Use(..) => "`use` import",
             ItemKind::Static(..) => "static item",
             ItemKind::Const(..) => "constant item",
-            ItemKind::Fn(..) => "function",
+            ItemKind::Fn { .. } => "function",
             ItemKind::Macro(..) => "macro",
             ItemKind::Mod(..) => "module",
             ItemKind::ForeignMod { .. } => "extern block",
@@ -4004,7 +4004,7 @@ impl<'hir> OwnerNode<'hir> {
         match self {
             OwnerNode::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. })
             | OwnerNode::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. })
-            | OwnerNode::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. })
+            | OwnerNode::Item(Item { kind: ItemKind::Fn { sig: fn_sig, .. }, .. })
             | OwnerNode::ForeignItem(ForeignItem {
                 kind: ForeignItemKind::Fn(fn_sig, _, _), ..
             }) => Some(fn_sig),
@@ -4016,7 +4016,7 @@ impl<'hir> OwnerNode<'hir> {
         match self {
             OwnerNode::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. })
             | OwnerNode::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. })
-            | OwnerNode::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. })
+            | OwnerNode::Item(Item { kind: ItemKind::Fn { sig: fn_sig, .. }, .. })
             | OwnerNode::ForeignItem(ForeignItem {
                 kind: ForeignItemKind::Fn(fn_sig, _, _), ..
             }) => Some(fn_sig.decl),
@@ -4030,7 +4030,7 @@ impl<'hir> OwnerNode<'hir> {
                 kind:
                     ItemKind::Static(_, _, body)
                     | ItemKind::Const(_, _, body)
-                    | ItemKind::Fn(_, _, body),
+                    | ItemKind::Fn { body, .. },
                 ..
             })
             | OwnerNode::TraitItem(TraitItem {
@@ -4206,7 +4206,7 @@ impl<'hir> Node<'hir> {
         match self {
             Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. })
             | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. })
-            | Node::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. })
+            | Node::Item(Item { kind: ItemKind::Fn { sig: fn_sig, .. }, .. })
             | Node::ForeignItem(ForeignItem { kind: ForeignItemKind::Fn(fn_sig, _, _), .. }) => {
                 Some(fn_sig.decl)
             }
@@ -4236,7 +4236,7 @@ impl<'hir> Node<'hir> {
         match self {
             Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. })
             | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(fn_sig, _), .. })
-            | Node::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. })
+            | Node::Item(Item { kind: ItemKind::Fn { sig: fn_sig, .. }, .. })
             | Node::ForeignItem(ForeignItem { kind: ForeignItemKind::Fn(fn_sig, _, _), .. }) => {
                 Some(fn_sig)
             }
@@ -4281,7 +4281,7 @@ impl<'hir> Node<'hir> {
             Node::Item(Item {
                 owner_id,
                 kind:
-                    ItemKind::Const(_, _, body) | ItemKind::Static(.., body) | ItemKind::Fn(.., body),
+                    ItemKind::Const(_, _, body) | ItemKind::Static(.., body) | ItemKind::Fn { body, .. },
                 ..
             })
             | Node::TraitItem(TraitItem {
@@ -4338,7 +4338,7 @@ impl<'hir> Node<'hir> {
     pub fn fn_kind(self) -> Option<FnKind<'hir>> {
         match self {
             Node::Item(i) => match i.kind {
-                ItemKind::Fn(ref sig, ref generics, _) => {
+                ItemKind::Fn { sig, generics, .. } => {
                     Some(FnKind::ItemFn(i.ident, generics, sig.header))
                 }
                 _ => None,
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index a73cf367c0e..85e555d903b 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -509,7 +509,7 @@ pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) -> V::
             try_visit!(visitor.visit_generics(generics));
             try_visit!(visitor.visit_nested_body(body));
         }
-        ItemKind::Fn(ref sig, ref generics, body_id) => {
+        ItemKind::Fn { sig, generics, body: body_id, .. } => {
             try_visit!(visitor.visit_id(item.hir_id()));
             try_visit!(visitor.visit_fn(
                 FnKind::ItemFn(item.ident, generics, sig.header),
diff --git a/compiler/rustc_hir/src/target.rs b/compiler/rustc_hir/src/target.rs
index 6ff57396b4a..f3e8f059c9e 100644
--- a/compiler/rustc_hir/src/target.rs
+++ b/compiler/rustc_hir/src/target.rs
@@ -106,7 +106,7 @@ impl Target {
             ItemKind::Use(..) => Target::Use,
             ItemKind::Static { .. } => Target::Static,
             ItemKind::Const(..) => Target::Const,
-            ItemKind::Fn(..) => Target::Fn,
+            ItemKind::Fn { .. } => Target::Fn,
             ItemKind::Macro(..) => Target::MacroDef,
             ItemKind::Mod(..) => Target::Mod,
             ItemKind::ForeignMod { .. } => Target::ForeignMod,
diff --git a/compiler/rustc_hir_analysis/src/check/entry.rs b/compiler/rustc_hir_analysis/src/check/entry.rs
index 245085b332c..332ac2fa0c0 100644
--- a/compiler/rustc_hir_analysis/src/check/entry.rs
+++ b/compiler/rustc_hir_analysis/src/check/entry.rs
@@ -44,7 +44,7 @@ fn check_main_fn_ty(tcx: TyCtxt<'_>, main_def_id: DefId) {
             return None;
         }
         match tcx.hir_node_by_def_id(def_id.expect_local()) {
-            Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, generics, _), .. }) => {
+            Node::Item(hir::Item { kind: hir::ItemKind::Fn { generics, .. }, .. }) => {
                 generics.params.is_empty().not().then_some(generics.span)
             }
             _ => {
@@ -58,7 +58,7 @@ fn check_main_fn_ty(tcx: TyCtxt<'_>, main_def_id: DefId) {
             return None;
         }
         match tcx.hir_node_by_def_id(def_id.expect_local()) {
-            Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, generics, _), .. }) => {
+            Node::Item(hir::Item { kind: hir::ItemKind::Fn { generics, .. }, .. }) => {
                 Some(generics.where_clause_span)
             }
             _ => {
@@ -79,7 +79,7 @@ fn check_main_fn_ty(tcx: TyCtxt<'_>, main_def_id: DefId) {
             return None;
         }
         match tcx.hir_node_by_def_id(def_id.expect_local()) {
-            Node::Item(hir::Item { kind: hir::ItemKind::Fn(fn_sig, _, _), .. }) => {
+            Node::Item(hir::Item { kind: hir::ItemKind::Fn { sig: fn_sig, .. }, .. }) => {
                 Some(fn_sig.decl.output.span())
             }
             _ => {
@@ -201,7 +201,7 @@ fn check_start_fn_ty(tcx: TyCtxt<'_>, start_def_id: DefId) {
     match start_t.kind() {
         ty::FnDef(..) => {
             if let Node::Item(it) = tcx.hir_node(start_id) {
-                if let hir::ItemKind::Fn(sig, generics, _) = &it.kind {
+                if let hir::ItemKind::Fn { sig, generics, .. } = &it.kind {
                     let mut error = false;
                     if !generics.params.is_empty() {
                         tcx.dcx().emit_err(errors::StartFunctionParameters { span: generics.span });
diff --git a/compiler/rustc_hir_analysis/src/check/intrinsic.rs b/compiler/rustc_hir_analysis/src/check/intrinsic.rs
index fd78bf3e8fc..747431e5312 100644
--- a/compiler/rustc_hir_analysis/src/check/intrinsic.rs
+++ b/compiler/rustc_hir_analysis/src/check/intrinsic.rs
@@ -26,7 +26,7 @@ fn equate_intrinsic_type<'tcx>(
     sig: ty::PolyFnSig<'tcx>,
 ) {
     let (generics, span) = match tcx.hir_node_by_def_id(def_id) {
-        hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, generics, _), .. })
+        hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn { generics, .. }, .. })
         | hir::Node::ForeignItem(hir::ForeignItem {
             kind: hir::ForeignItemKind::Fn(_, _, generics),
             ..
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index efffb24c81d..81a5e9ee90d 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -293,7 +293,7 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) -> Result<()
             }
             res
         }
-        hir::ItemKind::Fn(ref sig, ..) => {
+        hir::ItemKind::Fn { sig, .. } => {
             check_item_fn(tcx, def_id, item.ident, item.span, sig.decl)
         }
         hir::ItemKind::Static(ty, ..) => {
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index ada70117b62..b7da2538ec2 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -788,7 +788,7 @@ fn lower_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
             }
         }
 
-        hir::ItemKind::Fn(..) => {
+        hir::ItemKind::Fn { .. } => {
             tcx.ensure().generics_of(def_id);
             tcx.ensure().type_of(def_id);
             tcx.ensure().predicates_of(def_id);
@@ -1297,7 +1297,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_, ty::PolyFn
             generics,
             ..
         })
-        | Item(hir::Item { kind: ItemKind::Fn(sig, generics, _), .. }) => {
+        | Item(hir::Item { kind: ItemKind::Fn { sig, generics, .. }, .. }) => {
             lower_fn_sig_recovering_infer_ret_ty(&icx, sig, generics, def_id)
         }
 
diff --git a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
index 8f84492146f..0c19e2e4c51 100644
--- a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
@@ -969,7 +969,7 @@ pub(super) fn const_conditions<'tcx>(
     {
         Node::Item(item) => match item.kind {
             hir::ItemKind::Impl(impl_) => (impl_.generics, None, false),
-            hir::ItemKind::Fn(_, generics, _) => (generics, None, false),
+            hir::ItemKind::Fn { generics, .. } => (generics, None, false),
             hir::ItemKind::Trait(_, _, generics, supertraits, _) => {
                 (generics, Some((item.owner_id.def_id, supertraits)), false)
             }
diff --git a/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs b/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
index 7c65e9613b6..e8706d1adfb 100644
--- a/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
+++ b/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
@@ -660,7 +660,7 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
             _ => {}
         }
         match item.kind {
-            hir::ItemKind::Fn(_, generics, _) => {
+            hir::ItemKind::Fn { generics, .. } => {
                 self.visit_early_late(item.hir_id(), generics, |this| {
                     intravisit::walk_item(this, item);
                 });
@@ -1379,7 +1379,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
             } else if let Some(body_id) = outermost_body {
                 let fn_id = self.tcx.hir().body_owner(body_id);
                 match self.tcx.hir_node(fn_id) {
-                    Node::Item(hir::Item { owner_id, kind: hir::ItemKind::Fn(..), .. })
+                    Node::Item(hir::Item { owner_id, kind: hir::ItemKind::Fn { .. }, .. })
                     | Node::TraitItem(hir::TraitItem {
                         owner_id,
                         kind: hir::TraitItemKind::Fn(..),
diff --git a/compiler/rustc_hir_analysis/src/collect/type_of.rs b/compiler/rustc_hir_analysis/src/collect/type_of.rs
index c0526903e88..b8d8c2d9463 100644
--- a/compiler/rustc_hir_analysis/src/collect/type_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/type_of.rs
@@ -293,7 +293,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_
                 }
                 _ => icx.lower_ty(*self_ty),
             },
-            ItemKind::Fn(..) => {
+            ItemKind::Fn { .. } => {
                 let args = ty::GenericArgs::identity_for_item(tcx, def_id);
                 Ty::new_fn_def(tcx, def_id.to_def_id(), args)
             }
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
index fd49e7e4439..b7d3617fbe7 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
@@ -189,9 +189,9 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         // 2. Functions inside trait blocks
         // 3. Functions inside impl blocks
         let (sig, generics) = match tcx.hir_node_by_def_id(parent_id) {
-            hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, generics, _), .. }) => {
-                (sig, generics)
-            }
+            hir::Node::Item(hir::Item {
+                kind: hir::ItemKind::Fn { sig, generics, .. }, ..
+            }) => (sig, generics),
             hir::Node::TraitItem(hir::TraitItem {
                 kind: hir::TraitItemKind::Fn(sig, _),
                 generics,
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
index 5c1c5892190..42c98ab434e 100644
--- a/compiler/rustc_hir_pretty/src/lib.rs
+++ b/compiler/rustc_hir_pretty/src/lib.rs
@@ -634,7 +634,7 @@ impl<'a> State<'a> {
                 self.word(";");
                 self.end(); // end the outer cbox
             }
-            hir::ItemKind::Fn(ref sig, generics, body) => {
+            hir::ItemKind::Fn { sig, generics, body, .. } => {
                 self.head("");
                 self.print_fn(
                     sig.decl,
diff --git a/compiler/rustc_hir_typeck/src/_match.rs b/compiler/rustc_hir_typeck/src/_match.rs
index 87300f5bb83..3d40c5ee804 100644
--- a/compiler/rustc_hir_typeck/src/_match.rs
+++ b/compiler/rustc_hir_typeck/src/_match.rs
@@ -391,7 +391,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         if let hir::Node::Block(block) = node {
             // check that the body's parent is an fn
             let parent = self.tcx.parent_hir_node(self.tcx.parent_hir_id(block.hir_id));
-            if let (Some(expr), hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(..), .. })) =
+            if let (Some(expr), hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn { .. }, .. })) =
                 (&block.expr, parent)
             {
                 // check that the `if` expr without `else` is the fn body's expr
diff --git a/compiler/rustc_hir_typeck/src/callee.rs b/compiler/rustc_hir_typeck/src/callee.rs
index e2a26ddacab..28b1a823dae 100644
--- a/compiler/rustc_hir_typeck/src/callee.rs
+++ b/compiler/rustc_hir_typeck/src/callee.rs
@@ -705,7 +705,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             for id in self.tcx.hir().items() {
                 if let Some(node) = self.tcx.hir().get_if_local(id.owner_id.into())
                     && let hir::Node::Item(item) = node
-                    && let hir::ItemKind::Fn(..) = item.kind
+                    && let hir::ItemKind::Fn { .. } = item.kind
                     && item.ident.name == segment.ident.name
                 {
                     err.span_label(
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 8ba9a4bab57..2fa8110cf3a 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -1127,7 +1127,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let encl_item_id = self.tcx.hir().get_parent_item(expr.hir_id);
 
         if let hir::Node::Item(hir::Item {
-            kind: hir::ItemKind::Fn(..), span: encl_fn_span, ..
+            kind: hir::ItemKind::Fn { .. },
+            span: encl_fn_span,
+            ..
         })
         | hir::Node::TraitItem(hir::TraitItem {
             kind: hir::TraitItemKind::Fn(_, hir::TraitFn::Provided(_)),
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
index b77071523a6..2f6e50c8014 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
@@ -891,7 +891,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self.tcx.hir().get_fn_id_for_return_block(blk_id).and_then(|item_id| {
             match self.tcx.hir_node(item_id) {
                 Node::Item(&hir::Item {
-                    kind: hir::ItemKind::Fn(ref sig, ..), owner_id, ..
+                    kind: hir::ItemKind::Fn { sig, .. }, owner_id, ..
                 }) => Some((owner_id.def_id, sig.decl)),
                 Node::TraitItem(&hir::TraitItem {
                     kind: hir::TraitItemKind::Fn(ref sig, ..),
@@ -920,7 +920,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         )) => {
                             let (sig, owner_id) = match self.tcx.parent_hir_node(hir_id) {
                                 Node::Item(&hir::Item {
-                                    kind: hir::ItemKind::Fn(ref sig, ..),
+                                    kind: hir::ItemKind::Fn { ref sig, .. },
                                     owner_id,
                                     ..
                                 }) => (sig, owner_id),
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index d02e669e790..2f4b42587fb 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -2041,7 +2041,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     fn parent_item_span(&self, id: HirId) -> Option<Span> {
         let node = self.tcx.hir_node_by_def_id(self.tcx.hir().get_parent_item(id).def_id);
         match node {
-            Node::Item(&hir::Item { kind: hir::ItemKind::Fn(_, _, body_id), .. })
+            Node::Item(&hir::Item { kind: hir::ItemKind::Fn { body: body_id, .. }, .. })
             | Node::ImplItem(&hir::ImplItem { kind: hir::ImplItemKind::Fn(_, body_id), .. }) => {
                 let body = self.tcx.hir().body(body_id);
                 if let ExprKind::Block(block, _) = &body.value.kind {
@@ -2189,7 +2189,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 }
                             }
                             hir::Node::Item(item) => {
-                                if let hir::ItemKind::Fn(..) = item.kind {
+                                if let hir::ItemKind::Fn { .. } = item.kind {
                                     break;
                                 }
                             }
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index 964ef5b2106..3756f6339a4 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -981,14 +981,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let hir::Node::Item(hir::Item {
             kind:
-                hir::ItemKind::Fn(
-                    hir::FnSig {
-                        decl: hir::FnDecl { inputs: fn_parameters, output: fn_return, .. },
-                        ..
-                    },
-                    hir::Generics { params, predicates, .. },
-                    _body_id,
-                ),
+                hir::ItemKind::Fn {
+                    sig:
+                        hir::FnSig {
+                            decl: hir::FnDecl { inputs: fn_parameters, output: fn_return, .. },
+                            ..
+                        },
+                    generics: hir::Generics { params, predicates, .. },
+                    ..
+                },
             ..
         }) = fn_node
         else {
diff --git a/compiler/rustc_hir_typeck/src/upvar.rs b/compiler/rustc_hir_typeck/src/upvar.rs
index b3085843141..53993ba8d6c 100644
--- a/compiler/rustc_hir_typeck/src/upvar.rs
+++ b/compiler/rustc_hir_typeck/src/upvar.rs
@@ -1935,7 +1935,7 @@ fn drop_location_span(tcx: TyCtxt<'_>, hir_id: HirId) -> Span {
     let owner_node = tcx.hir_node(owner_id);
     let owner_span = match owner_node {
         hir::Node::Item(item) => match item.kind {
-            hir::ItemKind::Fn(_, _, owner_id) => tcx.hir().span(owner_id.hir_id),
+            hir::ItemKind::Fn { body: owner_id, .. } => tcx.hir().span(owner_id.hir_id),
             _ => {
                 bug!("Drop location span error: need to handle more ItemKind '{:?}'", item.kind);
             }
diff --git a/compiler/rustc_incremental/src/persist/dirty_clean.rs b/compiler/rustc_incremental/src/persist/dirty_clean.rs
index b99872e7ae6..35e5c250f78 100644
--- a/compiler/rustc_incremental/src/persist/dirty_clean.rs
+++ b/compiler/rustc_incremental/src/persist/dirty_clean.rs
@@ -253,7 +253,7 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
                     HirItem::Const(..) => ("ItemConst", LABELS_CONST),
 
                     // A function declaration
-                    HirItem::Fn(..) => ("ItemFn", LABELS_FN),
+                    HirItem::Fn { .. } => ("ItemFn", LABELS_FN),
 
                     // // A module
                     HirItem::Mod(..) => ("ItemMod", LABELS_HIR_ONLY),
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 6e823957cc6..2feed5e80dc 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -1030,7 +1030,7 @@ impl<'tcx> LateLintPass<'tcx> for InvalidNoMangleItems {
             }
         };
         match it.kind {
-            hir::ItemKind::Fn(.., generics, _) => {
+            hir::ItemKind::Fn { generics, .. } => {
                 if let Some(no_mangle_attr) = attr::find_by_name(attrs, sym::no_mangle) {
                     check_no_mangle_on_generic_fn(no_mangle_attr, None, generics, it.span);
                 }
diff --git a/compiler/rustc_lint/src/impl_trait_overcaptures.rs b/compiler/rustc_lint/src/impl_trait_overcaptures.rs
index b5dd6cf16ee..7f603f6a655 100644
--- a/compiler/rustc_lint/src/impl_trait_overcaptures.rs
+++ b/compiler/rustc_lint/src/impl_trait_overcaptures.rs
@@ -112,7 +112,7 @@ declare_lint_pass!(
 impl<'tcx> LateLintPass<'tcx> for ImplTraitOvercaptures {
     fn check_item(&mut self, cx: &LateContext<'tcx>, it: &'tcx hir::Item<'tcx>) {
         match &it.kind {
-            hir::ItemKind::Fn(..) => check_fn(cx.tcx, it.owner_id.def_id),
+            hir::ItemKind::Fn { .. } => check_fn(cx.tcx, it.owner_id.def_id),
             _ => {}
         }
     }
diff --git a/compiler/rustc_lint/src/types.rs b/compiler/rustc_lint/src/types.rs
index ef9aa11ef7b..3bd27a224e7 100644
--- a/compiler/rustc_lint/src/types.rs
+++ b/compiler/rustc_lint/src/types.rs
@@ -1561,7 +1561,7 @@ impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDefinitions {
                 );
             }
             // See `check_fn`..
-            hir::ItemKind::Fn(..) => {}
+            hir::ItemKind::Fn { .. } => {}
             // See `check_field_def`..
             hir::ItemKind::Union(..) | hir::ItemKind::Struct(..) | hir::ItemKind::Enum(..) => {}
             // Doesn't define something that can contain a external type to be checked.
diff --git a/compiler/rustc_middle/src/hir/map/mod.rs b/compiler/rustc_middle/src/hir/map/mod.rs
index 308078ddf87..dee4c424387 100644
--- a/compiler/rustc_middle/src/hir/map/mod.rs
+++ b/compiler/rustc_middle/src/hir/map/mod.rs
@@ -634,7 +634,7 @@ impl<'hir> Map<'hir> {
         for (hir_id, node) in self.parent_iter(hir_id) {
             if let Node::Item(Item {
                 kind:
-                    ItemKind::Fn(..)
+                    ItemKind::Fn { .. }
                     | ItemKind::Const(..)
                     | ItemKind::Static(..)
                     | ItemKind::Mod(..)
@@ -823,7 +823,7 @@ impl<'hir> Map<'hir> {
 
         let span = match self.tcx.hir_node(hir_id) {
             // Function-like.
-            Node::Item(Item { kind: ItemKind::Fn(sig, ..), span: outer_span, .. })
+            Node::Item(Item { kind: ItemKind::Fn { sig, .. }, span: outer_span, .. })
             | Node::TraitItem(TraitItem {
                 kind: TraitItemKind::Fn(sig, ..),
                 span: outer_span,
@@ -1149,7 +1149,7 @@ fn hir_id_to_string(map: Map<'_>, id: HirId) -> String {
                 ItemKind::Use(..) => "use",
                 ItemKind::Static(..) => "static",
                 ItemKind::Const(..) => "const",
-                ItemKind::Fn(..) => "fn",
+                ItemKind::Fn { .. } => "fn",
                 ItemKind::Macro(..) => "macro",
                 ItemKind::Mod(..) => "mod",
                 ItemKind::ForeignMod { .. } => "foreign mod",
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 12f715a0fe4..7656ca86c18 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -1646,7 +1646,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         };
 
         let Some(ItemLike::Item(Item {
-            kind: ItemKind::Fn(FnSig { decl, .. }, generics, _), ..
+            kind: ItemKind::Fn { sig: FnSig { decl, .. }, generics, .. },
+            ..
         })) = item
         else {
             bug!("should be a function item");
diff --git a/compiler/rustc_passes/src/naked_functions.rs b/compiler/rustc_passes/src/naked_functions.rs
index cad488bd71d..1e165b22e51 100644
--- a/compiler/rustc_passes/src/naked_functions.rs
+++ b/compiler/rustc_passes/src/naked_functions.rs
@@ -30,7 +30,10 @@ fn check_mod_naked_functions(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
         }
 
         let (fn_header, body_id) = match tcx.hir_node_by_def_id(def_id) {
-            hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, _, body_id), .. })
+            hir::Node::Item(hir::Item {
+                kind: hir::ItemKind::Fn { sig, body: body_id, .. },
+                ..
+            })
             | hir::Node::TraitItem(hir::TraitItem {
                 kind: hir::TraitItemKind::Fn(sig, hir::TraitFn::Provided(body_id)),
                 ..
diff --git a/compiler/rustc_passes/src/reachable.rs b/compiler/rustc_passes/src/reachable.rs
index 0ec151ceb45..7788adb6e17 100644
--- a/compiler/rustc_passes/src/reachable.rs
+++ b/compiler/rustc_passes/src/reachable.rs
@@ -141,7 +141,7 @@ impl<'tcx> ReachableContext<'tcx> {
 
         match self.tcx.hir_node_by_def_id(def_id) {
             Node::Item(item) => match item.kind {
-                hir::ItemKind::Fn(..) => recursively_reachable(self.tcx, def_id.into()),
+                hir::ItemKind::Fn { .. } => recursively_reachable(self.tcx, def_id.into()),
                 _ => false,
             },
             Node::TraitItem(trait_method) => match trait_method.kind {
@@ -200,7 +200,7 @@ impl<'tcx> ReachableContext<'tcx> {
         match *node {
             Node::Item(item) => {
                 match item.kind {
-                    hir::ItemKind::Fn(.., body) => {
+                    hir::ItemKind::Fn { body, .. } => {
                         if recursively_reachable(self.tcx, item.owner_id.into()) {
                             self.visit_nested_body(body);
                         }
diff --git a/compiler/rustc_passes/src/stability.rs b/compiler/rustc_passes/src/stability.rs
index d3637dac6b7..30f9e698521 100644
--- a/compiler/rustc_passes/src/stability.rs
+++ b/compiler/rustc_passes/src/stability.rs
@@ -428,7 +428,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Annotator<'a, 'tcx> {
                     )
                 }
             }
-            hir::ItemKind::Fn(ref item_fn_sig, _, _) => {
+            hir::ItemKind::Fn { sig: ref item_fn_sig, .. } => {
                 fn_sig = Some(item_fn_sig);
             }
             _ => {}
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index 9ae2d981ab0..e484cfed06b 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -654,7 +654,7 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             }
             hir::ItemKind::Const(..)
             | hir::ItemKind::Static(..)
-            | hir::ItemKind::Fn(..)
+            | hir::ItemKind::Fn { .. }
             | hir::ItemKind::TyAlias(..) => {
                 if let Some(item_ev) = item_ev {
                     self.reach(item.owner_id.def_id, item_ev).generics().predicates().ty();
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
index ee5ce19cb4d..d71938b40fe 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs
@@ -1978,7 +1978,9 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             return None;
         };
         let tykind = match self.tcx.hir_node_by_def_id(trace.cause.body_id) {
-            hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, _, body_id), .. }) => {
+            hir::Node::Item(hir::Item {
+                kind: hir::ItemKind::Fn { body: body_id, .. }, ..
+            }) => {
                 let body = hir.body(*body_id);
                 struct LetVisitor {
                     span: Span,
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs
index b97f3dc303b..2cfccc57c97 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs
@@ -630,7 +630,7 @@ impl<T> Trait<T> for X {
         let callable_scope = matches!(
             body_owner,
             Some(
-                hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(..), .. })
+                hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn { .. }, .. })
                     | hir::Node::TraitItem(hir::TraitItem { kind: hir::TraitItemKind::Fn(..), .. })
                     | hir::Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), .. }),
             )
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/suggest.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/suggest.rs
index 08775df5ac9..36270e0da78 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/suggest.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/suggest.rs
@@ -817,7 +817,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     pat.walk(&mut find_compatible_candidates);
                 }
 
-                hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, _, body), .. })
+                hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn { body, .. }, .. })
                 | hir::Node::ImplItem(hir::ImplItem {
                     kind: hir::ImplItemKind::Fn(_, body), ..
                 })
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
index 885b606326c..f9a30408326 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
@@ -913,7 +913,9 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         }
         let hir_id = self.tcx.local_def_id_to_hir_id(obligation.cause.body_id);
         let body_id = match self.tcx.hir_node(hir_id) {
-            hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, _, body_id), .. }) => body_id,
+            hir::Node::Item(hir::Item {
+                kind: hir::ItemKind::Fn { body: body_id, .. }, ..
+            }) => body_id,
             _ => return false,
         };
         let ControlFlow::Break(expr) = (FindMethodSubexprOfTry { search_span: span })
@@ -2910,7 +2912,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     })
                     .collect::<Option<Vec<ArgKind>>>()?,
             ),
-            Node::Item(&hir::Item { kind: hir::ItemKind::Fn(ref sig, ..), .. })
+            Node::Item(&hir::Item { kind: hir::ItemKind::Fn { ref sig, .. }, .. })
             | Node::ImplItem(&hir::ImplItem { kind: hir::ImplItemKind::Fn(ref sig, _), .. })
             | Node::TraitItem(&hir::TraitItem {
                 kind: hir::TraitItemKind::Fn(ref sig, _), ..
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
index a401fcf3505..51efe39a7bc 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/on_unimplemented.rs
@@ -91,7 +91,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
     /// to be the enclosing (async) block/function/closure
     fn describe_enclosure(&self, def_id: LocalDefId) -> Option<&'static str> {
         match self.tcx.hir_node_by_def_id(def_id) {
-            hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(..), .. }) => Some("a function"),
+            hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn { .. }, .. }) => Some("a function"),
             hir::Node::TraitItem(hir::TraitItem { kind: hir::TraitItemKind::Fn(..), .. }) => {
                 Some("a trait method")
             }
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
index 1b8b35f18df..e052634ad4c 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
@@ -311,7 +311,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     ..
                 })
                 | hir::Node::Item(hir::Item {
-                    kind: hir::ItemKind::Fn(fn_sig, generics, _), ..
+                    kind: hir::ItemKind::Fn { sig: fn_sig, generics, .. },
+                    ..
                 }) if projection.is_some() => {
                     // Missing restriction on associated type of type parameter (unmet projection).
                     suggest_restriction(
@@ -355,7 +356,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         | hir::ItemKind::Union(_, generics)
                         | hir::ItemKind::Trait(_, _, generics, ..)
                         | hir::ItemKind::Impl(hir::Impl { generics, .. })
-                        | hir::ItemKind::Fn(_, generics, _)
+                        | hir::ItemKind::Fn { generics, .. }
                         | hir::ItemKind::TyAlias(_, generics)
                         | hir::ItemKind::Const(_, generics, _)
                         | hir::ItemKind::TraitAlias(generics, _),
@@ -420,7 +421,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         | hir::ItemKind::Union(_, generics)
                         | hir::ItemKind::Trait(_, _, generics, ..)
                         | hir::ItemKind::Impl(hir::Impl { generics, .. })
-                        | hir::ItemKind::Fn(_, generics, _)
+                        | hir::ItemKind::Fn { generics, .. }
                         | hir::ItemKind::TyAlias(_, generics)
                         | hir::ItemKind::Const(_, generics, _)
                         | hir::ItemKind::TraitAlias(generics, _),
@@ -846,7 +847,9 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     };
                     name.to_string()
                 }
-                Some(hir::Node::Item(hir::Item { ident, kind: hir::ItemKind::Fn(..), .. })) => {
+                Some(hir::Node::Item(hir::Item {
+                    ident, kind: hir::ItemKind::Fn { .. }, ..
+                })) => {
                     err.span_label(ident.span, "consider calling this function");
                     ident.to_string()
                 }
@@ -1711,7 +1714,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     ) -> bool {
         let hir = self.tcx.hir();
         let node = self.tcx.hir_node_by_def_id(obligation.cause.body_id);
-        if let hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, _, body_id), .. }) = node
+        if let hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn {sig, body: body_id, .. }, .. }) = node
             && let hir::ExprKind::Block(blk, _) = &hir.body(*body_id).value.kind
             && sig.decl.output.span().overlaps(span)
             && blk.expr.is_none()
@@ -1745,7 +1748,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     }
 
     pub(super) fn return_type_span(&self, obligation: &PredicateObligation<'tcx>) -> Option<Span> {
-        let hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, ..), .. }) =
+        let hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn { sig, .. }, .. }) =
             self.tcx.hir_node_by_def_id(obligation.cause.body_id)
         else {
             return None;
@@ -1859,7 +1862,10 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
 
         let hir = self.tcx.hir();
         let node = self.tcx.hir_node_by_def_id(obligation.cause.body_id);
-        if let hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, _, body_id), .. }) = node {
+        if let hir::Node::Item(hir::Item {
+            kind: hir::ItemKind::Fn { body: body_id, .. }, ..
+        }) = node
+        {
             let body = hir.body(*body_id);
             // Point at all the `return`s in the function as they have failed trait bounds.
             let mut visitor = ReturnsVisitor::default();
@@ -4737,7 +4743,9 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
             node: hir::Node<'hir>,
         ) -> Option<(&'hir hir::FnDecl<'hir>, hir::BodyId)> {
             match node {
-                hir::Node::Item(item) if let hir::ItemKind::Fn(sig, _, body_id) = item.kind => {
+                hir::Node::Item(item)
+                    if let hir::ItemKind::Fn { sig, body: body_id, .. } = item.kind =>
+                {
                     Some((sig.decl, body_id))
                 }
                 hir::Node::ImplItem(item)
diff --git a/compiler/rustc_trait_selection/src/errors.rs b/compiler/rustc_trait_selection/src/errors.rs
index 700c79a7065..a8fddff4e4a 100644
--- a/compiler/rustc_trait_selection/src/errors.rs
+++ b/compiler/rustc_trait_selection/src/errors.rs
@@ -520,7 +520,7 @@ impl Subdiagnostic for AddLifetimeParamsSuggestion<'_> {
             let is_impl = matches!(&node, hir::Node::ImplItem(_));
             let (generics, parent_generics) = match node {
                 hir::Node::Item(&hir::Item {
-                    kind: hir::ItemKind::Fn(_, ref generics, ..),
+                    kind: hir::ItemKind::Fn { ref generics, .. },
                     ..
                 })
                 | hir::Node::TraitItem(&hir::TraitItem { ref generics, .. })