Revert "Create const block DefIds in typeck instead of ast lowering"

This reverts commit ddc5f9b.

Author: oli-obk

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

@@ -74,7 +74,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
             let kind = match &e.kind {
                 ExprKind::Array(exprs) => hir::ExprKind::Array(self.lower_exprs(exprs)),
-                ExprKind::ConstBlock(c) => hir::ExprKind::ConstBlock(self.lower_expr(c)),
+                ExprKind::ConstBlock(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);
                     let count = self.lower_array_length(count);

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_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

@@ -1623,6 +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> {
@@ -1909,7 +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.
@@ -3641,6 +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>),
@@ -3701,6 +3710,7 @@ impl<'hir> Node<'hir> {
             Node::PreciseCapturingNonLifetimeArg(a) => Some(a.ident),
             Node::Param(..)
             | Node::AnonConst(..)
+            | Node::ConstBlock(..)
             | Node::Expr(..)
             | Node::Stmt(..)
             | Node::Block(..)
@@ -3798,6 +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,
         }
@@ -3866,6 +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_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));
 

compiler/rustc_hir_typeck/src/upvar.rs

@@ -149,6 +149,10 @@ impl<'a, 'tcx> Visitor<'tcx> for InferBorrowKindVisitor<'a, 'tcx> {
                 self.visit_body(body);
                 self.fcx.analyze_closure(expr.hir_id, expr.span, body_id, body, capture_clause);
             }
+            hir::ExprKind::ConstBlock(anon_const) => {
+                let body = self.fcx.tcx.hir().body(anon_const.body);
+                self.visit_body(body);
+            }
             _ => {}
         }
 

compiler/rustc_hir_typeck/src/writeback.rs

@@ -3,7 +3,6 @@
 // generic parameters.
 
 use crate::FnCtxt;
-use hir::def::DefKind;
 use rustc_data_structures::unord::ExtendUnord;
 use rustc_errors::{ErrorGuaranteed, StashKey};
 use rustc_hir as hir;
@@ -17,7 +16,7 @@ use rustc_middle::ty::fold::{TypeFoldable, TypeFolder};
 use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::TypeSuperFoldable;
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_span::symbol::{kw, sym};
+use rustc_span::symbol::sym;
 use rustc_span::Span;
 use rustc_trait_selection::solve;
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt;
@@ -296,11 +295,11 @@ impl<'cx, 'tcx> Visitor<'tcx> for WritebackCx<'cx, 'tcx> {
             hir::ExprKind::Field(..) | hir::ExprKind::OffsetOf(..) => {
                 self.visit_field_id(e.hir_id);
             }
-            hir::ExprKind::ConstBlock(_) => {
-                let feed = self.tcx().create_def(self.fcx.body_id, kw::Empty, DefKind::InlineConst);
-                feed.def_span(e.span);
-                feed.local_def_id_to_hir_id(e.hir_id);
-                self.typeck_results.inline_consts.insert(e.hir_id.local_id, feed.def_id());
+            hir::ExprKind::ConstBlock(anon_const) => {
+                self.visit_node_id(e.span, anon_const.hir_id);
+
+                let body = self.tcx().hir().body(anon_const.body);
+                self.visit_body(body);
             }
             _ => {}
         }