Rollup merge of #133589 - voidc:remove-array-len, r=boxyuwu

Remove `hir::ArrayLen`

This refactoring removes `hir::ArrayLen`, replacing it with `hir::ConstArg`. To represent inferred array lengths (previously `hir::ArrayLen::Infer`), a new variant `ConstArgKind::Infer` is added.

r? `@BoxyUwU`

5 files changed, 9 insertions, 16 deletions

diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index cf062e82cb6..8d5824130d8 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -151,11 +151,11 @@ impl<'v> Visitor<'v> for HirPlaceholderCollector {
             _ => {}
         }
     }
-    fn visit_array_length(&mut self, length: &'v hir::ArrayLen<'v>) {
-        if let hir::ArrayLen::Infer(inf) = length {
-            self.0.push(inf.span);
+    fn visit_const_arg(&mut self, const_arg: &'v hir::ConstArg<'v>) {
+        if let hir::ConstArgKind::Infer(span) = const_arg.kind {
+            self.0.push(span);
         }
-        intravisit::walk_array_len(self, length)
+        intravisit::walk_const_arg(self, const_arg)
     }
 }
 
diff --git a/compiler/rustc_hir_analysis/src/collect/generics_of.rs b/compiler/rustc_hir_analysis/src/collect/generics_of.rs
index c31bff28fd3..077696ac1f2 100644
--- a/compiler/rustc_hir_analysis/src/collect/generics_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/generics_of.rs
@@ -181,7 +181,7 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
                     // expressions' count (i.e. `N` in `[x; N]`), and explicit
                     // `enum` discriminants (i.e. `D` in `enum Foo { Bar = D }`),
                     // as they shouldn't be able to cause query cycle errors.
-                    Node::Expr(Expr { kind: ExprKind::Repeat(_, ArrayLen::Body(ct)), .. })
+                    Node::Expr(Expr { kind: ExprKind::Repeat(_, ct), .. })
                         if ct.anon_const_hir_id() == Some(hir_id) =>
                     {
                         Some(parent_did)
diff --git a/compiler/rustc_hir_analysis/src/collect/type_of.rs b/compiler/rustc_hir_analysis/src/collect/type_of.rs
index 18fb5bfd912..7cf99bebd36 100644
--- a/compiler/rustc_hir_analysis/src/collect/type_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/type_of.rs
@@ -145,7 +145,7 @@ fn const_arg_anon_type_of<'tcx>(tcx: TyCtxt<'tcx>, arg_hir_id: HirId, span: Span
         // Easy case: arrays repeat expressions.
         Node::Ty(&hir::Ty { kind: TyKind::Array(_, ref constant), .. })
         | Node::Expr(&Expr { kind: ExprKind::Repeat(_, ref constant), .. })
-            if constant.hir_id() == arg_hir_id =>
+            if constant.hir_id == arg_hir_id =>
         {
             return tcx.types.usize;
         }
@@ -579,8 +579,6 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_
             x => bug!("unexpected non-type Node::GenericParam: {:?}", x),
         },
 
-        Node::ArrayLenInfer(_) => tcx.types.usize,
-
         x => {
             bug!("unexpected sort of node in type_of(): {:?}", x);
         }
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs
index ae1279d428c..c3f4fc8699a 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs
@@ -104,7 +104,7 @@ fn generic_arg_mismatch_err(
             GenericArg::Type(hir::Ty { kind: hir::TyKind::Array(_, len), .. }),
             GenericParamDefKind::Const { .. },
         ) if tcx.type_of(param.def_id).skip_binder() == tcx.types.usize => {
-            let snippet = sess.source_map().span_to_snippet(tcx.hir().span(len.hir_id()));
+            let snippet = sess.source_map().span_to_snippet(tcx.hir().span(len.hir_id));
             if let Ok(snippet) = snippet {
                 err.span_suggestion(
                     arg.span(),
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
index cf780a3d3bb..7b8e95f3434 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
@@ -2090,6 +2090,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 format!("Const::lower_const_arg: invalid qpath {qpath:?}"),
             ),
             hir::ConstArgKind::Anon(anon) => Const::from_anon_const(tcx, anon.def_id),
+            hir::ConstArgKind::Infer(span) => self.ct_infer(None, span),
         }
     }
 
@@ -2310,13 +2311,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 tcx.at(span).type_of(def_id).instantiate(tcx, args)
             }
             hir::TyKind::Array(ty, length) => {
-                let length = match length {
-                    hir::ArrayLen::Infer(inf) => self.ct_infer(None, inf.span),
-                    hir::ArrayLen::Body(constant) => {
-                        self.lower_const_arg(constant, FeedConstTy::No)
-                    }
-                };
-
+                let length = self.lower_const_arg(length, FeedConstTy::No);
                 Ty::new_array_with_const_len(tcx, self.lower_ty(ty), length)
             }
             hir::TyKind::Typeof(e) => tcx.type_of(e.def_id).instantiate_identity(),