Auto merge of #124650 - oli-obk:pattern_types_syntax, r=nnethercote

Create const block DefIds in typeck instead of ast lowering

this is a prerequisite for cleaning up pattern types and the range pattern HIR nodes in general. Right now they contain expressions, but they are supposed to only contain constants. In order to generate the anonymous constants lazily during typeck, we need to support generating new items with bodies during typeck in general. Transforming const blocks was the simplest change I could find to allow us to do that (everything else is much more invasive if we haven't already done it for const blocks).

Author: bors

compiler/rustc_ast/src/ast.rs

@@ -1393,7 +1393,7 @@ pub enum ExprKind {
     /// An array (e.g, `[a, b, c, d]`).
     Array(ThinVec<P<Expr>>),
     /// Allow anonymous constants from an inline `const` block
-    ConstBlock(AnonConst),
+    ConstBlock(P<Expr>),
     /// A function call
     ///
     /// The first field resolves to the function itself,

compiler/rustc_ast/src/mut_visit.rs

@@ -1411,7 +1411,7 @@ pub fn noop_visit_expr<T: MutVisitor>(
     match kind {
         ExprKind::Array(exprs) => visit_thin_exprs(exprs, vis),
         ExprKind::ConstBlock(anon_const) => {
-            vis.visit_anon_const(anon_const);
+            vis.visit_expr(anon_const);
         }
         ExprKind::Repeat(expr, count) => {
             vis.visit_expr(expr);

compiler/rustc_ast/src/visit.rs

@@ -951,7 +951,7 @@ 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_anon_const(anon_const)),
+        ExprKind::ConstBlock(anon_const) => try_visit!(visitor.visit_expr(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

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

compiler/rustc_ast_lowering/src/index.rs

@@ -236,14 +236,6 @@ 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

@@ -96,6 +96,8 @@ 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.
@@ -158,6 +160,7 @@ 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,
@@ -567,6 +570,7 @@ 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 =
@@ -593,6 +597,7 @@ 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;
@@ -629,6 +634,7 @@ 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() {
@@ -646,7 +652,7 @@ 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 };
+        let nodes = hir::OwnerNodes { opt_hash_including_bodies, nodes, bodies, has_inline_consts };
         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

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

compiler/rustc_const_eval/src/const_eval/fn_queries.rs

@@ -38,7 +38,6 @@ 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
         }
@@ -57,6 +56,7 @@ 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_const_eval/src/const_eval/machine.rs

@@ -6,7 +6,6 @@ use std::ops::ControlFlow;
 use rustc_ast::Mutability;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::fx::IndexEntry;
-use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::LangItem;
@@ -392,18 +391,7 @@ impl<'tcx> interpret::Machine<'tcx> for CompileTimeInterpreter<'tcx> {
         instance: ty::InstanceDef<'tcx>,
     ) -> InterpResult<'tcx, &'tcx mir::Body<'tcx>> {
         match instance {
-            ty::InstanceDef::Item(def) => {
-                if ecx.tcx.is_ctfe_mir_available(def) {
-                    Ok(ecx.tcx.mir_for_ctfe(def))
-                } else if ecx.tcx.def_kind(def) == DefKind::AssocConst {
-                    ecx.tcx.dcx().bug("This is likely a const item that is missing from its impl");
-                } else {
-                    // `find_mir_or_eval_fn` checks that this is a const fn before even calling us,
-                    // so this should be unreachable.
-                    let path = ecx.tcx.def_path_str(def);
-                    bug!("trying to call extern function `{path}` at compile-time");
-                }
-            }
+            ty::InstanceDef::Item(def) => Ok(ecx.tcx.mir_for_ctfe(def)),
             _ => Ok(ecx.tcx.instance_mir(instance)),
         }
     }

compiler/rustc_hir/src/hir.rs

@@ -876,6 +876,9 @@ 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> {
@@ -1592,14 +1595,6 @@ 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> {
@@ -1886,7 +1881,7 @@ 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(ConstBlock),
+    ConstBlock(&'hir Expr<'hir>),
     /// An array (e.g., `[a, b, c, d]`).
     Array(&'hir [Expr<'hir>]),
     /// A function call.
@@ -3609,7 +3604,6 @@ 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>),
@@ -3670,7 +3664,6 @@ impl<'hir> Node<'hir> {
             Node::PreciseCapturingNonLifetimeArg(a) => Some(a.ident),
             Node::Param(..)
             | Node::AnonConst(..)
-            | Node::ConstBlock(..)
             | Node::Expr(..)
             | Node::Stmt(..)
             | Node::Block(..)
@@ -3768,7 +3761,6 @@ impl<'hir> Node<'hir> {
             }
 
             Node::AnonConst(constant) => Some((constant.def_id, constant.body)),
-            Node::ConstBlock(constant) => Some((constant.def_id, constant.body)),
 
             _ => None,
         }
@@ -3837,7 +3829,6 @@ 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

@@ -344,9 +344,6 @@ 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)
     }
@@ -716,22 +713,14 @@ 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_inline_const(const_block))
+            try_visit!(visitor.visit_expr(const_block))
         }
         ExprKind::Repeat(ref element, ref count) => {
             try_visit!(visitor.visit_expr(element));

compiler/rustc_hir/src/stable_hash_impls.rs

@@ -93,7 +93,8 @@ 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: _ } = *self;
+        let OwnerNodes { opt_hash_including_bodies, nodes: _, bodies: _, has_inline_consts: _ } =
+            *self;
         opt_hash_including_bodies.unwrap().hash_stable(hcx, hasher);
     }
 }