Auto merge of rust-lang#125918 - oli-obk:const_block_ice, r=compiler-…

…errors

Revert: create const block bodies in typeck via query feeding

as per the discussion in rust-lang#125806 (comment)

It was a mistake to try to shoehorn const blocks and some specific anon consts into the same box and feed them during typeck. It turned out not simplifying anything (my hope was that we could feed `type_of` to start avoiding the huge HIR matcher, but that didn't work out), but instead making a few things more fragile.

reverts the const-block-specific parts of rust-lang#124650

`@bors` rollup=never had a small perf impact previously

fixes rust-lang#125846

r? `@compiler-errors`

compiler/rustc_ast/src/ast.rs

@@ -1392,7 +1392,7 @@ pub enum ExprKind {
     /// An array (e.g, `[a, b, c, d]`).
     Array(ThinVec<P<Expr>>),
     /// Allow anonymous constants from an inline `const` block
-    ConstBlock(P<Expr>),
+    ConstBlock(AnonConst),
     /// A function call
     ///
     /// The first field resolves to the function itself,

compiler/rustc_ast/src/mut_visit.rs

@@ -1417,7 +1417,7 @@ pub fn noop_visit_expr<T: MutVisitor>(
     match kind {
         ExprKind::Array(exprs) => visit_thin_exprs(exprs, vis),
         ExprKind::ConstBlock(anon_const) => {
-            vis.visit_expr(anon_const);
+            vis.visit_anon_const(anon_const);
         }
         ExprKind::Repeat(expr, count) => {
             vis.visit_expr(expr);

compiler/rustc_ast/src/visit.rs

@@ -959,7 +959,7 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) -> V
         ExprKind::Array(subexpressions) => {
             walk_list!(visitor, visit_expr, subexpressions);
         }
-        ExprKind::ConstBlock(anon_const) => try_visit!(visitor.visit_expr(anon_const)),
+        ExprKind::ConstBlock(anon_const) => try_visit!(visitor.visit_anon_const(anon_const)),
         ExprKind::Repeat(element, count) => {
             try_visit!(visitor.visit_expr(element));
             try_visit!(visitor.visit_anon_const(count));

compiler/rustc_ast_lowering/src/expr.rs

@@ -75,8 +75,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
             let kind = match &e.kind {
                 ExprKind::Array(exprs) => hir::ExprKind::Array(self.lower_exprs(exprs)),
                 ExprKind::ConstBlock(c) => {
-                    self.has_inline_consts = true;
-                    hir::ExprKind::ConstBlock(self.lower_expr(c))
+                    let c = self.with_new_scopes(c.value.span, |this| hir::ConstBlock {
+                        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)),
+                    });
+                    hir::ExprKind::ConstBlock(c)
                 }
                 ExprKind::Repeat(expr, count) => {
                     let expr = self.lower_expr(expr);

compiler/rustc_ast_lowering/src/index.rs

@@ -236,6 +236,14 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         });
     }
 
+    fn visit_inline_const(&mut self, constant: &'hir ConstBlock) {
+        self.insert(DUMMY_SP, constant.hir_id, Node::ConstBlock(constant));
+
+        self.with_parent(constant.hir_id, |this| {
+            intravisit::walk_inline_const(this, constant);
+        });
+    }
+
     fn visit_expr(&mut self, expr: &'hir Expr<'hir>) {
         self.insert(expr.span, expr.hir_id, Node::Expr(expr));
 

compiler/rustc_ast_lowering/src/lib.rs

@@ -96,8 +96,6 @@ struct LoweringContext<'a, 'hir> {
 
     /// Bodies inside the owner being lowered.
     bodies: Vec<(hir::ItemLocalId, &'hir hir::Body<'hir>)>,
-    /// Whether there were inline consts that typeck will split out into bodies
-    has_inline_consts: bool,
     /// Attributes inside the owner being lowered.
     attrs: SortedMap<hir::ItemLocalId, &'hir [Attribute]>,
     /// Collect items that were created by lowering the current owner.
@@ -160,7 +158,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             item_local_id_counter: hir::ItemLocalId::ZERO,
             node_id_to_local_id: Default::default(),
             trait_map: Default::default(),
-            has_inline_consts: false,
 
             // Lowering state.
             catch_scope: None,
@@ -570,7 +567,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
         let current_attrs = std::mem::take(&mut self.attrs);
         let current_bodies = std::mem::take(&mut self.bodies);
-        let current_has_inline_consts = std::mem::take(&mut self.has_inline_consts);
         let current_node_ids = std::mem::take(&mut self.node_id_to_local_id);
         let current_trait_map = std::mem::take(&mut self.trait_map);
         let current_owner =
@@ -597,7 +593,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
         self.attrs = current_attrs;
         self.bodies = current_bodies;
-        self.has_inline_consts = current_has_inline_consts;
         self.node_id_to_local_id = current_node_ids;
         self.trait_map = current_trait_map;
         self.current_hir_id_owner = current_owner;
@@ -634,7 +629,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let attrs = std::mem::take(&mut self.attrs);
         let mut bodies = std::mem::take(&mut self.bodies);
         let trait_map = std::mem::take(&mut self.trait_map);
-        let has_inline_consts = std::mem::take(&mut self.has_inline_consts);
 
         #[cfg(debug_assertions)]
         for (id, attrs) in attrs.iter() {
@@ -652,7 +646,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             self.tcx.hash_owner_nodes(node, &bodies, &attrs);
         let num_nodes = self.item_local_id_counter.as_usize();
         let (nodes, parenting) = index::index_hir(self.tcx, node, &bodies, num_nodes);
-        let nodes = hir::OwnerNodes { opt_hash_including_bodies, nodes, bodies, has_inline_consts };
+        let nodes = hir::OwnerNodes { opt_hash_including_bodies, nodes, bodies };
         let attrs = hir::AttributeMap { map: attrs, opt_hash: attrs_hash };
 
         self.arena.alloc(hir::OwnerInfo { nodes, parenting, attrs, trait_map })

compiler/rustc_ast_pretty/src/pprust/state/expr.rs

@@ -380,9 +380,8 @@ impl<'a> State<'a> {
             ast::ExprKind::Array(exprs) => {
                 self.print_expr_vec(exprs);
             }
-            ast::ExprKind::ConstBlock(expr) => {
-                self.word_space("const");
-                self.print_expr(expr, FixupContext::default());
+            ast::ExprKind::ConstBlock(anon_const) => {
+                self.print_expr_anon_const(anon_const, attrs);
             }
             ast::ExprKind::Repeat(element, count) => {
                 self.print_expr_repeat(element, count);

compiler/rustc_const_eval/src/const_eval/fn_queries.rs

@@ -38,6 +38,7 @@ fn constness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Constness {
     match node {
         hir::Node::Ctor(_)
         | hir::Node::AnonConst(_)
+        | hir::Node::ConstBlock(_)
         | hir::Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(..), .. }) => {
             hir::Constness::Const
         }
@@ -56,7 +57,6 @@ fn constness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Constness {
             if is_const { hir::Constness::Const } else { hir::Constness::NotConst }
         }
         hir::Node::Expr(e) if let hir::ExprKind::Closure(c) = e.kind => c.constness,
-        hir::Node::Expr(e) if let hir::ExprKind::ConstBlock(_) = e.kind => hir::Constness::Const,
         _ => {
             if let Some(fn_kind) = node.fn_kind() {
                 if fn_kind.constness() == hir::Constness::Const {

compiler/rustc_hir/src/hir.rs

@@ -907,9 +907,6 @@ pub struct OwnerNodes<'tcx> {
     pub nodes: IndexVec<ItemLocalId, ParentedNode<'tcx>>,
     /// Content of local bodies.
     pub bodies: SortedMap<ItemLocalId, &'tcx Body<'tcx>>,
-    /// Whether the body contains inline constants that are created for the query system during typeck
-    /// of the body.
-    pub has_inline_consts: bool,
 }
 
 impl<'tcx> OwnerNodes<'tcx> {
@@ -1626,6 +1623,14 @@ pub struct AnonConst {
     pub span: Span,
 }
 
+/// An inline constant expression `const { something }`.
+#[derive(Copy, Clone, Debug, HashStable_Generic)]
+pub struct ConstBlock {
+    pub hir_id: HirId,
+    pub def_id: LocalDefId,
+    pub body: BodyId,
+}
+
 /// An expression.
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub struct Expr<'hir> {
@@ -1912,7 +1917,7 @@ pub fn is_range_literal(expr: &Expr<'_>) -> bool {
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub enum ExprKind<'hir> {
     /// Allow anonymous constants from an inline `const` block
-    ConstBlock(&'hir Expr<'hir>),
+    ConstBlock(ConstBlock),
     /// An array (e.g., `[a, b, c, d]`).
     Array(&'hir [Expr<'hir>]),
     /// A function call.
@@ -3644,6 +3649,7 @@ pub enum Node<'hir> {
     Variant(&'hir Variant<'hir>),
     Field(&'hir FieldDef<'hir>),
     AnonConst(&'hir AnonConst),
+    ConstBlock(&'hir ConstBlock),
     Expr(&'hir Expr<'hir>),
     ExprField(&'hir ExprField<'hir>),
     Stmt(&'hir Stmt<'hir>),
@@ -3704,6 +3710,7 @@ impl<'hir> Node<'hir> {
             Node::PreciseCapturingNonLifetimeArg(a) => Some(a.ident),
             Node::Param(..)
             | Node::AnonConst(..)
+            | Node::ConstBlock(..)
             | Node::Expr(..)
             | Node::Stmt(..)
             | Node::Block(..)
@@ -3801,6 +3808,7 @@ impl<'hir> Node<'hir> {
             }
 
             Node::AnonConst(constant) => Some((constant.def_id, constant.body)),
+            Node::ConstBlock(constant) => Some((constant.def_id, constant.body)),
 
             _ => None,
         }
@@ -3869,6 +3877,7 @@ impl<'hir> Node<'hir> {
         expect_variant,       &'hir Variant<'hir>,      Node::Variant(n),      n;
         expect_field,         &'hir FieldDef<'hir>,     Node::Field(n),        n;
         expect_anon_const,    &'hir AnonConst,          Node::AnonConst(n),    n;
+        expect_inline_const,  &'hir ConstBlock,         Node::ConstBlock(n),   n;
         expect_expr,          &'hir Expr<'hir>,         Node::Expr(n),         n;
         expect_expr_field,    &'hir ExprField<'hir>,    Node::ExprField(n),    n;
         expect_stmt,          &'hir Stmt<'hir>,         Node::Stmt(n),         n;

compiler/rustc_hir/src/intravisit.rs

@@ -344,6 +344,9 @@ pub trait Visitor<'v>: Sized {
     fn visit_anon_const(&mut self, c: &'v AnonConst) -> Self::Result {
         walk_anon_const(self, c)
     }
+    fn visit_inline_const(&mut self, c: &'v ConstBlock) -> Self::Result {
+        walk_inline_const(self, c)
+    }
     fn visit_expr(&mut self, ex: &'v Expr<'v>) -> Self::Result {
         walk_expr(self, ex)
     }
@@ -718,14 +721,22 @@ pub fn walk_anon_const<'v, V: Visitor<'v>>(visitor: &mut V, constant: &'v AnonCo
     visitor.visit_nested_body(constant.body)
 }
 
+pub fn walk_inline_const<'v, V: Visitor<'v>>(
+    visitor: &mut V,
+    constant: &'v ConstBlock,
+) -> V::Result {
+    try_visit!(visitor.visit_id(constant.hir_id));
+    visitor.visit_nested_body(constant.body)
+}
+
 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>) -> V::Result {
     try_visit!(visitor.visit_id(expression.hir_id));
     match expression.kind {
         ExprKind::Array(subexpressions) => {
             walk_list!(visitor, visit_expr, subexpressions);
         }
         ExprKind::ConstBlock(ref const_block) => {
-            try_visit!(visitor.visit_expr(const_block))
+            try_visit!(visitor.visit_inline_const(const_block))
         }
         ExprKind::Repeat(ref element, ref count) => {
             try_visit!(visitor.visit_expr(element));

compiler/rustc_hir/src/stable_hash_impls.rs

@@ -93,8 +93,7 @@ impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for OwnerNodes<'
         // `local_id_to_def_id` is also ignored because is dependent on the body, then just hashing
         // the body satisfies the condition of two nodes being different have different
         // `hash_stable` results.
-        let OwnerNodes { opt_hash_including_bodies, nodes: _, bodies: _, has_inline_consts: _ } =
-            *self;
+        let OwnerNodes { opt_hash_including_bodies, nodes: _, bodies: _ } = *self;
         opt_hash_including_bodies.unwrap().hash_stable(hcx, hasher);
     }
 }

compiler/rustc_hir_analysis/src/check/region.rs

@@ -407,14 +407,11 @@ 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(&hir::Closure { body, .. }) => {
+        hir::ExprKind::Closure(&hir::Closure { body, .. })
+        | hir::ExprKind::ConstBlock(hir::ConstBlock { body, .. }) => {
             let body = visitor.tcx.hir().body(body);
             visitor.visit_body(body);
         }
-        hir::ExprKind::ConstBlock(expr) => visitor.enter_body(expr.hir_id, |this| {
-            this.cx.var_parent = None;
-            resolve_local(this, None, Some(expr));
-        }),
         hir::ExprKind::AssignOp(_, left_expr, right_expr) => {
             debug!(
                 "resolve_expr - enabling pessimistic_yield, was previously {}",

compiler/rustc_hir_analysis/src/collect/generics_of.rs

@@ -177,10 +177,10 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
                 }
             }
         }
-        Node::Expr(&hir::Expr {
-            kind: hir::ExprKind::Closure { .. } | hir::ExprKind::ConstBlock { .. },
-            ..
-        }) => Some(tcx.typeck_root_def_id(def_id.to_def_id())),
+        Node::ConstBlock(_)
+        | Node::Expr(&hir::Expr { kind: hir::ExprKind::Closure { .. }, .. }) => {
+            Some(tcx.typeck_root_def_id(def_id.to_def_id()))
+        }
         Node::Item(item) => match item.kind {
             ItemKind::OpaqueTy(&hir::OpaqueTy {
                 origin:
@@ -415,7 +415,7 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
     }
 
     // provide junk type parameter defs for const blocks.
-    if let Node::Expr(Expr { kind: ExprKind::ConstBlock(..), .. }) = node {
+    if let Node::ConstBlock(_) = node {
         own_params.push(ty::GenericParamDef {
             index: next_index(),
             name: Symbol::intern("<const_ty>"),

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -485,7 +485,8 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_
         }
 
         Node::AnonConst(_) => anon_const_type_of(tcx, def_id),
-        Node::Expr(&Expr { kind: ExprKind::ConstBlock(..), .. }) => {
+
+        Node::ConstBlock(_) => {
             let args = ty::GenericArgs::identity_for_item(tcx, def_id.to_def_id());
             args.as_inline_const().ty()
         }

compiler/rustc_hir_analysis/src/lib.rs

@@ -190,6 +190,10 @@ pub fn check_crate(tcx: TyCtxt<'_>) {
         }
     });
 
+    // Freeze definitions as we don't add new ones at this point. This improves performance by
+    // allowing lock-free access to them.
+    tcx.untracked().definitions.freeze();
+
     // FIXME: Remove this when we implement creating `DefId`s
     // for anon constants during their parents' typeck.
     // Typeck all body owners in parallel will produce queries
@@ -201,10 +205,6 @@ pub fn check_crate(tcx: TyCtxt<'_>) {
         }
     });
 
-    // Freeze definitions as we don't add new ones at this point. This improves performance by
-    // allowing lock-free access to them.
-    tcx.untracked().definitions.freeze();
-
     tcx.ensure().check_unused_traits(());
 }
 

compiler/rustc_hir_pretty/src/lib.rs

@@ -84,6 +84,7 @@ impl<'a> State<'a> {
             Node::ImplItem(a) => self.print_impl_item(a),
             Node::Variant(a) => self.print_variant(a),
             Node::AnonConst(a) => self.print_anon_const(a),
+            Node::ConstBlock(a) => self.print_inline_const(a),
             Node::Expr(a) => self.print_expr(a),
             Node::ExprField(a) => self.print_expr_field(a),
             Node::Stmt(a) => self.print_stmt(a),
@@ -1049,10 +1050,10 @@ impl<'a> State<'a> {
         self.end()
     }
 
-    fn print_inline_const(&mut self, constant: &hir::Expr<'_>) {
+    fn print_inline_const(&mut self, constant: &hir::ConstBlock) {
         self.ibox(INDENT_UNIT);
         self.word_space("const");
-        self.print_expr(constant);
+        self.ann.nested(self, Nested::Body(constant.body));
         self.end()
     }
 

compiler/rustc_hir_typeck/src/expr.rs

@@ -31,6 +31,7 @@ use rustc_errors::{
 use rustc_hir as hir;
 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_analysis::hir_ty_lowering::HirTyLowerer as _;
@@ -334,7 +335,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
             ExprKind::DropTemps(e) => self.check_expr_with_expectation(e, expected),
             ExprKind::Array(args) => self.check_expr_array(args, expected, expr),
-            ExprKind::ConstBlock(ref block) => self.check_expr_with_expectation(block, expected),
+            ExprKind::ConstBlock(ref block) => self.check_expr_const_block(block, expected),
             ExprKind::Repeat(element, ref count) => {
                 self.check_expr_repeat(element, count, expected, expr)
             }
@@ -1456,6 +1457,24 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    fn check_expr_const_block(
+        &self,
+        block: &'tcx hir::ConstBlock,
+        expected: Expectation<'tcx>,
+    ) -> Ty<'tcx> {
+        let body = self.tcx.hir().body(block.body);
+
+        // Create a new function context.
+        let def_id = block.def_id;
+        let fcx = FnCtxt::new(self, self.param_env, def_id);
+        crate::GatherLocalsVisitor::new(&fcx).visit_body(body);
+
+        let ty = fcx.check_expr_with_expectation(body.value, expected);
+        fcx.require_type_is_sized(ty, body.value.span, ObligationCauseCode::ConstSized);
+        fcx.write_ty(block.hir_id, ty);
+        ty
+    }
+
     fn check_expr_repeat(
         &self,
         element: &'tcx hir::Expr<'tcx>,

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1051,10 +1051,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .take_while(|(_, node)| {
                     // look at parents until we find the first body owner
                     node.body_id().is_none()
-                        && !matches!(
-                            node,
-                            Node::Expr(Expr { kind: ExprKind::ConstBlock { .. }, .. })
-                        )
                 })
                 .any(|(parent_id, _)| self.is_loop(parent_id));