Make `hir::PathSegment::hir_id` non-optional.

15 files changed, 87 insertions, 79 deletions

diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index a41d4b01e0e..d31ec91fcaa 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -1776,13 +1776,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
         binding: hir::HirId,
         attrs: AttrVec,
     ) -> hir::Expr<'hir> {
+        let hir_id = self.next_id();
         let res = Res::Local(binding);
         let expr_path = hir::ExprKind::Path(hir::QPath::Resolved(
             None,
             self.arena.alloc(hir::Path {
                 span: self.lower_span(span),
                 res,
-                segments: arena_vec![self; hir::PathSegment::from_ident(ident, res)],
+                segments: arena_vec![self; hir::PathSegment::from_ident(ident, hir_id, res)],
             }),
         ));
 
diff --git a/compiler/rustc_ast_lowering/src/index.rs b/compiler/rustc_ast_lowering/src/index.rs
index 219e1b81d1e..61470d93bdb 100644
--- a/compiler/rustc_ast_lowering/src/index.rs
+++ b/compiler/rustc_ast_lowering/src/index.rs
@@ -246,9 +246,7 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
     }
 
     fn visit_path_segment(&mut self, path_span: Span, path_segment: &'hir PathSegment<'hir>) {
-        if let Some(hir_id) = path_segment.hir_id {
-            self.insert(path_span, hir_id, Node::PathSegment(path_segment));
-        }
+        self.insert(path_span, path_segment.hir_id, Node::PathSegment(path_segment));
         intravisit::walk_path_segment(self, path_span, path_segment);
     }
 
diff --git a/compiler/rustc_ast_lowering/src/item.rs b/compiler/rustc_ast_lowering/src/item.rs
index e3f02968d4d..778203acf7d 100644
--- a/compiler/rustc_ast_lowering/src/item.rs
+++ b/compiler/rustc_ast_lowering/src/item.rs
@@ -1431,13 +1431,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
             GenericParamKind::Const { .. } => None,
             GenericParamKind::Type { .. } => {
                 let def_id = self.local_def_id(id).to_def_id();
+                let hir_id = self.next_id();
                 let res = Res::Def(DefKind::TyParam, def_id);
                 let ty_path = self.arena.alloc(hir::Path {
                     span: param_span,
                     res,
                     segments: self
                         .arena
-                        .alloc_from_iter([hir::PathSegment::from_ident(ident, res)]),
+                        .alloc_from_iter([hir::PathSegment::from_ident(ident, hir_id, res)]),
                 });
                 let ty_id = self.next_id();
                 let bounded_ty =
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index bc183c6e313..097855bb6bf 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -1260,6 +1260,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 return self.lower_path_ty(t, qself, path, ParamMode::Explicit, itctx);
             }
             TyKind::ImplicitSelf => {
+                let hir_id = self.lower_node_id(t.id);
                 let res = self.expect_full_res(t.id);
                 let res = self.lower_res(res);
                 hir::TyKind::Path(hir::QPath::Resolved(
@@ -1268,6 +1269,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         res,
                         segments: arena_vec![self; hir::PathSegment::from_ident(
                             Ident::with_dummy_span(kw::SelfUpper),
+                            hir_id,
                             res
                         )],
                         span: self.lower_span(t.span),
@@ -2194,13 +2196,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             hir::PredicateOrigin::ImplTrait,
         );
 
+        let hir_id = self.next_id();
         let res = Res::Def(DefKind::TyParam, def_id.to_def_id());
         let ty = hir::TyKind::Path(hir::QPath::Resolved(
             None,
             self.arena.alloc(hir::Path {
                 span: self.lower_span(span),
                 res,
-                segments: arena_vec![self; hir::PathSegment::from_ident(self.lower_ident(ident), res)],
+                segments: arena_vec![self; hir::PathSegment::from_ident(self.lower_ident(ident), hir_id, res)],
             }),
         ));
 
diff --git a/compiler/rustc_ast_lowering/src/pat.rs b/compiler/rustc_ast_lowering/src/pat.rs
index 61c32816e17..a23f5fddc57 100644
--- a/compiler/rustc_ast_lowering/src/pat.rs
+++ b/compiler/rustc_ast_lowering/src/pat.rs
@@ -255,13 +255,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 )
             }
             Some(res) => {
+                let hir_id = self.next_id();
                 let res = self.lower_res(res);
                 hir::PatKind::Path(hir::QPath::Resolved(
                     None,
                     self.arena.alloc(hir::Path {
                         span: self.lower_span(ident.span),
                         res,
-                        segments: arena_vec![self; hir::PathSegment::from_ident(self.lower_ident(ident), res)],
+                        segments: arena_vec![self; hir::PathSegment::from_ident(self.lower_ident(ident), hir_id, res)],
                     }),
             ))
             }
diff --git a/compiler/rustc_ast_lowering/src/path.rs b/compiler/rustc_ast_lowering/src/path.rs
index 6ec8bcbc1e5..5f0ddd5ac1c 100644
--- a/compiler/rustc_ast_lowering/src/path.rs
+++ b/compiler/rustc_ast_lowering/src/path.rs
@@ -250,15 +250,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
 
         let res = self.expect_full_res(segment.id);
-        let id = self.lower_node_id(segment.id);
+        let hir_id = self.lower_node_id(segment.id);
         debug!(
             "lower_path_segment: ident={:?} original-id={:?} new-id={:?}",
-            segment.ident, segment.id, id,
+            segment.ident, segment.id, hir_id,
         );
 
         hir::PathSegment {
             ident: self.lower_ident(segment.ident),
-            hir_id: Some(id),
+            hir_id,
             res: self.lower_res(res),
             infer_args,
             args: if generic_args.is_empty() && generic_args.span.is_empty() {
diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index dd9590016b9..66d2614b190 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -935,10 +935,11 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 _,
             ) = hir_map.body(fn_body_id).value.kind
             {
-                let opt_suggestions = path_segment
-                    .hir_id
-                    .map(|path_hir_id| self.infcx.tcx.typeck(path_hir_id.owner))
-                    .and_then(|typeck| typeck.type_dependent_def_id(*hir_id))
+                let opt_suggestions = self
+                    .infcx
+                    .tcx
+                    .typeck(path_segment.hir_id.owner)
+                    .type_dependent_def_id(*hir_id)
                     .and_then(|def_id| self.infcx.tcx.impl_of_method(def_id))
                     .map(|def_id| self.infcx.tcx.associated_items(def_id))
                     .map(|assoc_items| {
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index bd53e7670a6..561045ff4ef 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -203,7 +203,7 @@ pub struct PathSegment<'hir> {
     /// The identifier portion of this path segment.
     pub ident: Ident,
 
-    pub hir_id: Option<HirId>,
+    pub hir_id: HirId,
 
     pub res: Res,
 
@@ -223,12 +223,12 @@ pub struct PathSegment<'hir> {
 
 impl<'hir> PathSegment<'hir> {
     /// Converts an identifier to the corresponding segment.
-    pub fn from_ident(ident: Ident, res: Res) -> PathSegment<'hir> {
-        PathSegment { ident, hir_id: None, res, infer_args: true, args: None }
+    pub fn from_ident(ident: Ident, hir_id: HirId, res: Res) -> PathSegment<'hir> {
+        PathSegment { ident, hir_id, res, infer_args: true, args: None }
     }
 
     pub fn invalid() -> Self {
-        Self::from_ident(Ident::empty(), Res::Err)
+        Self::from_ident(Ident::empty(), HirId::INVALID, Res::Err)
     }
 
     pub fn args(&self) -> &GenericArgs<'hir> {
diff --git a/compiler/rustc_hir/src/hir_id.rs b/compiler/rustc_hir/src/hir_id.rs
index 346ac9e9644..e586d5cd5d9 100644
--- a/compiler/rustc_hir/src/hir_id.rs
+++ b/compiler/rustc_hir/src/hir_id.rs
@@ -20,6 +20,9 @@ pub struct HirId {
 }
 
 impl HirId {
+    /// Signal local id which should never be used.
+    pub const INVALID: HirId = HirId { owner: CRATE_DEF_ID, local_id: ItemLocalId::INVALID };
+
     #[inline]
     pub fn expect_owner(self) -> LocalDefId {
         assert_eq!(self.local_id.index(), 0);
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index 3d5e22add71..036becf4b7c 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -724,7 +724,7 @@ pub fn walk_path_segment<'v, V: Visitor<'v>>(
     segment: &'v PathSegment<'v>,
 ) {
     visitor.visit_ident(segment.ident);
-    walk_list!(visitor, visit_id, segment.hir_id);
+    visitor.visit_id(segment.hir_id);
     if let Some(ref args) = segment.args {
         visitor.visit_generic_args(path_span, args);
     }
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 a20bcd93045..126c39c3bad 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
@@ -909,7 +909,7 @@ impl<'a, 'tcx> FindInferSourceVisitor<'a, 'tcx> {
                             None?
                         }
                         let substs = self.node_substs_opt(expr.hir_id)?;
-                        let span = tcx.hir().span(segment.hir_id?);
+                        let span = tcx.hir().span(segment.hir_id);
                         let insert_span = segment.ident.span.shrink_to_hi().with_hi(span.hi());
                         InsertableGenericArgs {
                             insert_span,
@@ -963,7 +963,7 @@ impl<'a, 'tcx> FindInferSourceVisitor<'a, 'tcx> {
                 if generics.has_impl_trait() {
                     return None;
                 }
-                let span = tcx.hir().span(segment.hir_id?);
+                let span = tcx.hir().span(segment.hir_id);
                 let insert_span = segment.ident.span.shrink_to_hi().with_hi(span.hi());
                 Some(InsertableGenericArgs {
                     insert_span,
@@ -996,7 +996,7 @@ impl<'a, 'tcx> FindInferSourceVisitor<'a, 'tcx> {
                     if !segment.infer_args || generics.has_impl_trait() {
                         None?;
                     }
-                    let span = tcx.hir().span(segment.hir_id?);
+                    let span = tcx.hir().span(segment.hir_id);
                     let insert_span = segment.ident.span.shrink_to_hi().with_hi(span.hi());
                     InsertableGenericArgs { insert_span, substs, generics_def_id: def_id, def_id }
                 };
diff --git a/compiler/rustc_save_analysis/src/dump_visitor.rs b/compiler/rustc_save_analysis/src/dump_visitor.rs
index 769d3243d58..f2b2daaf20b 100644
--- a/compiler/rustc_save_analysis/src/dump_visitor.rs
+++ b/compiler/rustc_save_analysis/src/dump_visitor.rs
@@ -912,7 +912,10 @@ impl<'tcx> DumpVisitor<'tcx> {
                     _,
                 )
                 | Res::SelfTy { .. } => {
-                    self.dump_path_segment_ref(id, &hir::PathSegment::from_ident(ident, Res::Err));
+                    self.dump_path_segment_ref(
+                        id,
+                        &hir::PathSegment::from_ident(ident, hir::HirId::INVALID, Res::Err),
+                    );
                 }
                 def => {
                     error!("unexpected definition kind when processing collected idents: {:?}", def)
diff --git a/compiler/rustc_save_analysis/src/lib.rs b/compiler/rustc_save_analysis/src/lib.rs
index 4b110b824e0..c58ccde4390 100644
--- a/compiler/rustc_save_analysis/src/lib.rs
+++ b/compiler/rustc_save_analysis/src/lib.rs
@@ -649,7 +649,7 @@ impl<'tcx> SaveContext<'tcx> {
     }
 
     pub fn get_path_segment_data(&self, path_seg: &hir::PathSegment<'_>) -> Option<Ref> {
-        self.get_path_segment_data_with_id(path_seg, path_seg.hir_id?)
+        self.get_path_segment_data_with_id(path_seg, path_seg.hir_id)
     }
 
     pub fn get_path_segment_data_with_id(
diff --git a/compiler/rustc_typeck/src/astconv/mod.rs b/compiler/rustc_typeck/src/astconv/mod.rs
index a49244d16d0..faf3d7a1000 100644
--- a/compiler/rustc_typeck/src/astconv/mod.rs
+++ b/compiler/rustc_typeck/src/astconv/mod.rs
@@ -1113,7 +1113,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             let ident = Ident::new(assoc_item.name, binding.item_name.span);
             let item_segment = hir::PathSegment {
                 ident,
-                hir_id: Some(binding.hir_id),
+                hir_id: binding.hir_id,
                 res: Res::Err,
                 args: Some(binding.gen_args),
                 infer_args: false,
diff --git a/compiler/rustc_typeck/src/structured_errors/wrong_number_of_generic_args.rs b/compiler/rustc_typeck/src/structured_errors/wrong_number_of_generic_args.rs
index d4b5e5e2fe4..eeb0e9ce738 100644
--- a/compiler/rustc_typeck/src/structured_errors/wrong_number_of_generic_args.rs
+++ b/compiler/rustc_typeck/src/structured_errors/wrong_number_of_generic_args.rs
@@ -291,62 +291,60 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
     // Creates lifetime name suggestions from the lifetime parameter names
     fn get_lifetime_args_suggestions_from_param_names(
         &self,
-        path_hir_id: Option<hir::HirId>,
+        path_hir_id: hir::HirId,
         num_params_to_take: usize,
     ) -> String {
         debug!(?path_hir_id);
 
-        if let Some(path_hir_id) = path_hir_id {
-            let mut ret = Vec::new();
-            for (id, node) in self.tcx.hir().parent_iter(path_hir_id) {
-                debug!(?id);
-                let params = if let Some(generics) = node.generics() {
-                    generics.params
-                } else if let hir::Node::Ty(ty) = node
-                    && let hir::TyKind::BareFn(bare_fn) = ty.kind
-                {
-                    bare_fn.generic_params
-                } else {
-                    &[]
-                };
-                ret.extend(params.iter().filter_map(|p| {
-                    let hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Explicit }
-                        = p.kind
-                    else { return None };
-                    let hir::ParamName::Plain(name) = p.name else { return None };
-                    Some(name.to_string())
-                }));
-                // Suggest `'static` when in const/static item-like.
-                if let hir::Node::Item(hir::Item {
-                    kind: hir::ItemKind::Static { .. } | hir::ItemKind::Const { .. },
-                    ..
-                })
-                | hir::Node::TraitItem(hir::TraitItem {
-                    kind: hir::TraitItemKind::Const { .. },
-                    ..
-                })
-                | hir::Node::ImplItem(hir::ImplItem {
-                    kind: hir::ImplItemKind::Const { .. },
-                    ..
-                })
-                | hir::Node::ForeignItem(hir::ForeignItem {
-                    kind: hir::ForeignItemKind::Static { .. },
-                    ..
-                })
-                | hir::Node::AnonConst(..) = node
-                {
-                    ret.extend(
-                        std::iter::repeat("'static".to_owned())
-                            .take(num_params_to_take.saturating_sub(ret.len())),
-                    );
-                }
-                if ret.len() >= num_params_to_take {
-                    return ret[..num_params_to_take].join(", ");
-                }
-                // We cannot refer to lifetimes defined in an outer function.
-                if let hir::Node::Item(_) = node {
-                    break;
-                }
+        let mut ret = Vec::new();
+        for (id, node) in self.tcx.hir().parent_iter(path_hir_id) {
+            debug!(?id);
+            let params = if let Some(generics) = node.generics() {
+                generics.params
+            } else if let hir::Node::Ty(ty) = node
+                && let hir::TyKind::BareFn(bare_fn) = ty.kind
+            {
+                bare_fn.generic_params
+            } else {
+                &[]
+            };
+            ret.extend(params.iter().filter_map(|p| {
+                let hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Explicit }
+                    = p.kind
+                else { return None };
+                let hir::ParamName::Plain(name) = p.name else { return None };
+                Some(name.to_string())
+            }));
+            // Suggest `'static` when in const/static item-like.
+            if let hir::Node::Item(hir::Item {
+                kind: hir::ItemKind::Static { .. } | hir::ItemKind::Const { .. },
+                ..
+            })
+            | hir::Node::TraitItem(hir::TraitItem {
+                kind: hir::TraitItemKind::Const { .. },
+                ..
+            })
+            | hir::Node::ImplItem(hir::ImplItem {
+                kind: hir::ImplItemKind::Const { .. },
+                ..
+            })
+            | hir::Node::ForeignItem(hir::ForeignItem {
+                kind: hir::ForeignItemKind::Static { .. },
+                ..
+            })
+            | hir::Node::AnonConst(..) = node
+            {
+                ret.extend(
+                    std::iter::repeat("'static".to_owned())
+                        .take(num_params_to_take.saturating_sub(ret.len())),
+                );
+            }
+            if ret.len() >= num_params_to_take {
+                return ret[..num_params_to_take].join(", ");
+            }
+            // We cannot refer to lifetimes defined in an outer function.
+            if let hir::Node::Item(_) = node {
+                break;
             }
         }
 
@@ -690,8 +688,7 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
             num = num_trait_generics_except_self,
         );
 
-        if let Some(hir_id) = self.path_segment.hir_id
-        && let Some(parent_node) = self.tcx.hir().find_parent_node(hir_id)
+        if let Some(parent_node) = self.tcx.hir().find_parent_node(self.path_segment.hir_id)
         && let Some(parent_node) = self.tcx.hir().find(parent_node)
         && let hir::Node::Expr(expr) = parent_node {
             match expr.kind {