put hir::AnonConst on the hir arena

compiler/rustc_ast_lowering/src/index.rs

@@ -375,7 +375,7 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         }
     }
 
-    fn visit_array_length(&mut self, len: &'hir ArrayLen) {
+    fn visit_array_length(&mut self, len: &'hir ArrayLen<'hir>) {
         match len {
             ArrayLen::Infer(inf) => self.insert(inf.span, inf.hir_id, Node::ArrayLenInfer(inf)),
             ArrayLen::Body(..) => intravisit::walk_array_len(self, len),

compiler/rustc_ast_lowering/src/item.rs

@@ -1588,11 +1588,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             }),
                         )),
                     )),
-                    default: Some(hir::AnonConst {
+                    default: Some(self.arena.alloc(hir::AnonConst {
                         def_id: anon_const,
                         hir_id: const_id,
                         body: const_body,
-                    }),
+                    })),
                     is_host_effect: true,
                 },
                 colon_span: None,

compiler/rustc_ast_lowering/src/lib.rs

@@ -1181,10 +1181,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                     tokens: None,
                                 };
 
-                                let ct = self.with_new_scopes(span, |this| hir::AnonConst {
+                                let ct = self.with_new_scopes(span, |this| {
+                                    self.arena.alloc(hir::AnonConst {
                                         def_id,
                                         hir_id: this.lower_node_id(node_id),
-                                    body: this.lower_const_body(path_expr.span, Some(&path_expr)),
+                                        body: this
+                                            .lower_const_body(path_expr.span, Some(&path_expr)),
+                                    })
                                 });
                                 return GenericArg::Const(ConstArg {
                                     value: ct,
@@ -2318,7 +2321,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
-    fn lower_array_length(&mut self, c: &AnonConst) -> hir::ArrayLen {
+    fn lower_array_length(&mut self, c: &AnonConst) -> hir::ArrayLen<'hir> {
         match c.value.kind {
             ExprKind::Underscore => {
                 if self.tcx.features().generic_arg_infer {
@@ -2341,12 +2344,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
     }
 
-    fn lower_anon_const(&mut self, c: &AnonConst) -> hir::AnonConst {
+    fn lower_anon_const(&mut self, c: &AnonConst) -> &'hir hir::AnonConst {
-        self.with_new_scopes(c.value.span, |this| hir::AnonConst {
+        self.arena.alloc(self.with_new_scopes(c.value.span, |this| hir::AnonConst {
             def_id: this.local_def_id(c.id),
             hir_id: this.lower_node_id(c.id),
             body: this.lower_const_body(c.value.span, Some(&c.value)),
-        })
+        }))
     }
 
     fn lower_unsafe_source(&mut self, u: UnsafeSource) -> hir::UnsafeSource {
@@ -2653,7 +2656,7 @@ impl<'hir> GenericArgsCtor<'hir> {
 
         lcx.children.push((def_id, hir::MaybeOwner::NonOwner(hir_id)));
         self.args.push(hir::GenericArg::Const(hir::ConstArg {
-            value: hir::AnonConst { def_id, hir_id, body },
+            value: lcx.arena.alloc(hir::AnonConst { def_id, hir_id, body }),
             span,
             is_desugared_from_effects: true,
         }))

compiler/rustc_hir/src/hir.rs

@@ -230,8 +230,8 @@ impl<'hir> PathSegment<'hir> {
 }
 
 #[derive(Clone, Copy, Debug, HashStable_Generic)]
-pub struct ConstArg {
+pub struct ConstArg<'hir> {
-    pub value: AnonConst,
+    pub value: &'hir AnonConst,
     pub span: Span,
     /// Indicates whether this comes from a `~const` desugaring.
     pub is_desugared_from_effects: bool,
@@ -253,7 +253,7 @@ impl InferArg {
 pub enum GenericArg<'hir> {
     Lifetime(&'hir Lifetime),
     Type(&'hir Ty<'hir>),
-    Const(ConstArg),
+    Const(ConstArg<'hir>),
     Infer(InferArg),
 }
 
@@ -491,7 +491,7 @@ pub enum GenericParamKind<'hir> {
     Const {
         ty: &'hir Ty<'hir>,
         /// Optional default value for the const generic param
-        default: Option<AnonConst>,
+        default: Option<&'hir AnonConst>,
         is_host_effect: bool,
     },
 }
@@ -1563,12 +1563,12 @@ impl fmt::Display for ConstContext {
 pub type Lit = Spanned<LitKind>;
 
 #[derive(Copy, Clone, Debug, HashStable_Generic)]
-pub enum ArrayLen {
+pub enum ArrayLen<'hir> {
     Infer(InferArg),
-    Body(AnonConst),
+    Body(&'hir AnonConst),
 }
 
-impl ArrayLen {
+impl ArrayLen<'_> {
     pub fn hir_id(&self) -> HirId {
         match self {
             ArrayLen::Infer(InferArg { hir_id, .. }) | ArrayLen::Body(AnonConst { hir_id, .. }) => {
@@ -1965,7 +1965,7 @@ pub enum ExprKind<'hir> {
     ///
     /// E.g., `[1; 5]`. The first expression is the element
     /// to be repeated; the second is the number of times to repeat it.
-    Repeat(&'hir Expr<'hir>, ArrayLen),
+    Repeat(&'hir Expr<'hir>, ArrayLen<'hir>),
 
     /// A suspension point for coroutines (i.e., `yield <expr>`).
     Yield(&'hir Expr<'hir>, YieldSource),
@@ -2345,7 +2345,7 @@ pub struct TypeBinding<'hir> {
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub enum Term<'hir> {
     Ty(&'hir Ty<'hir>),
-    Const(AnonConst),
+    Const(&'hir AnonConst),
 }
 
 impl<'hir> From<&'hir Ty<'hir>> for Term<'hir> {
@@ -2354,8 +2354,8 @@ impl<'hir> From<&'hir Ty<'hir>> for Term<'hir> {
     }
 }
 
-impl<'hir> From<AnonConst> for Term<'hir> {
+impl<'hir> From<&'hir AnonConst> for Term<'hir> {
-    fn from(c: AnonConst) -> Self {
+    fn from(c: &'hir AnonConst) -> Self {
         Term::Const(c)
     }
 }
@@ -2646,7 +2646,7 @@ pub enum TyKind<'hir> {
     /// A variable length slice (i.e., `[T]`).
     Slice(&'hir Ty<'hir>),
     /// A fixed length array (i.e., `[T; n]`).
-    Array(&'hir Ty<'hir>, ArrayLen),
+    Array(&'hir Ty<'hir>, ArrayLen<'hir>),
     /// A raw pointer (i.e., `*const T` or `*mut T`).
     Ptr(MutTy<'hir>),
     /// A reference (i.e., `&'a T` or `&'a mut T`).
@@ -2675,7 +2675,7 @@ pub enum TyKind<'hir> {
     /// where `Bound` is a trait or a lifetime.
     TraitObject(&'hir [PolyTraitRef<'hir>], &'hir Lifetime, TraitObjectSyntax),
     /// Unused for now.
-    Typeof(AnonConst),
+    Typeof(&'hir AnonConst),
     /// `TyKind::Infer` means the type should be inferred instead of it having been
     /// specified. This can appear anywhere in a type.
     Infer,
@@ -2708,10 +2708,10 @@ pub enum InlineAsmOperand<'hir> {
         out_expr: Option<&'hir Expr<'hir>>,
     },
     Const {
-        anon_const: AnonConst,
+        anon_const: &'hir AnonConst,
     },
     SymFn {
-        anon_const: AnonConst,
+        anon_const: &'hir AnonConst,
     },
     SymStatic {
         path: QPath<'hir>,
@@ -2913,7 +2913,7 @@ pub struct Variant<'hir> {
     /// Fields and constructor id of the variant.
     pub data: VariantData<'hir>,
     /// Explicit discriminant (e.g., `Foo = 1`).
-    pub disr_expr: Option<AnonConst>,
+    pub disr_expr: Option<&'hir AnonConst>,
     /// Span
     pub span: Span,
 }
@@ -3833,7 +3833,7 @@ mod size_asserts {
     static_assert_size!(FnDecl<'_>, 40);
     static_assert_size!(ForeignItem<'_>, 72);
     static_assert_size!(ForeignItemKind<'_>, 40);
-    static_assert_size!(GenericArg<'_>, 32);
+    static_assert_size!(GenericArg<'_>, 24);
     static_assert_size!(GenericBound<'_>, 48);
     static_assert_size!(Generics<'_>, 56);
     static_assert_size!(Impl<'_>, 80);

compiler/rustc_hir/src/intravisit.rs

@@ -338,7 +338,7 @@ pub trait Visitor<'v>: Sized {
     fn visit_pat_field(&mut self, f: &'v PatField<'v>) -> Self::Result {
         walk_pat_field(self, f)
     }
-    fn visit_array_length(&mut self, len: &'v ArrayLen) -> Self::Result {
+    fn visit_array_length(&mut self, len: &'v ArrayLen<'v>) -> Self::Result {
         walk_array_len(self, len)
     }
     fn visit_anon_const(&mut self, c: &'v AnonConst) -> Self::Result {
@@ -703,7 +703,7 @@ pub fn walk_pat_field<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v PatField<'
     visitor.visit_pat(field.pat)
 }
 
-pub fn walk_array_len<'v, V: Visitor<'v>>(visitor: &mut V, len: &'v ArrayLen) -> V::Result {
+pub fn walk_array_len<'v, V: Visitor<'v>>(visitor: &mut V, len: &'v ArrayLen<'v>) -> V::Result {
     match len {
         // FIXME: Use `visit_infer` here.
         ArrayLen::Infer(InferArg { hir_id, span: _ }) => visitor.visit_id(*hir_id),

compiler/rustc_hir_analysis/src/collect.rs

@@ -143,7 +143,7 @@ impl<'v> Visitor<'v> for HirPlaceholderCollector {
             _ => {}
         }
     }
-    fn visit_array_length(&mut self, length: &'v hir::ArrayLen) {
+    fn visit_array_length(&mut self, length: &'v hir::ArrayLen<'v>) {
         if let hir::ArrayLen::Infer(inf) = length {
             self.0.push(inf.span);
         }

compiler/rustc_hir_pretty/src/lib.rs

@@ -968,7 +968,7 @@ impl<'a> State<'a> {
         self.print_else(elseopt)
     }
 
-    fn print_array_length(&mut self, len: &hir::ArrayLen) {
+    fn print_array_length(&mut self, len: &hir::ArrayLen<'_>) {
         match len {
             hir::ArrayLen::Infer(..) => self.word("_"),
             hir::ArrayLen::Body(ct) => self.print_anon_const(ct),
@@ -1052,7 +1052,7 @@ impl<'a> State<'a> {
         self.end()
     }
 
-    fn print_expr_repeat(&mut self, element: &hir::Expr<'_>, count: &hir::ArrayLen) {
+    fn print_expr_repeat(&mut self, element: &hir::Expr<'_>, count: &hir::ArrayLen<'_>) {
         self.ibox(INDENT_UNIT);
         self.word("[");
         self.print_expr(element);

compiler/rustc_hir_typeck/src/expr.rs

@@ -1444,7 +1444,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             return;
         };
         if let hir::TyKind::Array(_, length) = ty.peel_refs().kind
-            && let hir::ArrayLen::Body(hir::AnonConst { hir_id, .. }) = length
+            && let hir::ArrayLen::Body(&hir::AnonConst { hir_id, .. }) = length
         {
             let span = self.tcx.hir().span(hir_id);
             self.dcx().try_steal_modify_and_emit_err(
@@ -1483,7 +1483,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     fn check_expr_repeat(
         &self,
         element: &'tcx hir::Expr<'tcx>,
-        count: &'tcx hir::ArrayLen,
+        count: &'tcx hir::ArrayLen<'tcx>,
         expected: Expectation<'tcx>,
         expr: &'tcx hir::Expr<'tcx>,
     ) -> Ty<'tcx> {

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -439,7 +439,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    pub fn lower_array_length(&self, length: &hir::ArrayLen) -> ty::Const<'tcx> {
+    pub fn lower_array_length(&self, length: &hir::ArrayLen<'tcx>) -> ty::Const<'tcx> {
         match length {
             hir::ArrayLen::Infer(inf) => self.ct_infer(self.tcx.types.usize, None, inf.span),
             hir::ArrayLen::Body(anon_const) => {

src/librustdoc/clean/mod.rs

@@ -281,7 +281,10 @@ fn clean_lifetime<'tcx>(lifetime: &hir::Lifetime, cx: &mut DocContext<'tcx>) ->
     Lifetime(lifetime.ident.name)
 }
 
-pub(crate) fn clean_const<'tcx>(constant: &hir::ConstArg, cx: &mut DocContext<'tcx>) -> Constant {
+pub(crate) fn clean_const<'tcx>(
+    constant: &hir::ConstArg<'_>,
+    cx: &mut DocContext<'tcx>,
+) -> Constant {
     let def_id = cx.tcx.hir().body_owner_def_id(constant.value.body).to_def_id();
     Constant {
         type_: Box::new(clean_middle_ty(
@@ -2450,7 +2453,7 @@ pub(crate) fn clean_variant_def_with_args<'tcx>(
 
 fn clean_variant_data<'tcx>(
     variant: &hir::VariantData<'tcx>,
-    disr_expr: &Option<hir::AnonConst>,
+    disr_expr: &Option<&hir::AnonConst>,
     cx: &mut DocContext<'tcx>,
 ) -> Variant {
     let discriminant = disr_expr

src/tools/clippy/clippy_utils/src/hir_utils.rs

@@ -224,7 +224,7 @@ impl HirEqInterExpr<'_, '_, '_> {
         })
     }
 
-    pub fn eq_array_length(&mut self, left: ArrayLen, right: ArrayLen) -> bool {
+    pub fn eq_array_length(&mut self, left: ArrayLen<'_>, right: ArrayLen<'_>) -> bool {
         match (left, right) {
             (ArrayLen::Infer(..), ArrayLen::Infer(..)) => true,
             (ArrayLen::Body(l_ct), ArrayLen::Body(r_ct)) => self.eq_body(l_ct.body, r_ct.body),
@@ -1116,7 +1116,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
         }
     }
 
-    pub fn hash_array_length(&mut self, length: ArrayLen) {
+    pub fn hash_array_length(&mut self, length: ArrayLen<'_>) {
         match length {
             ArrayLen::Infer(..) => {},
             ArrayLen::Body(anon_const) => self.hash_body(anon_const.body),