Add ConstItemRhs and revert to using BodyId for non type_consts

Author: camelid

compiler/rustc_ast/src/ast.rs

@@ -3754,10 +3754,29 @@ pub struct ConstItem {
     pub ident: Ident,
     pub generics: Generics,
     pub ty: Box<Ty>,
-    pub body: Option<Box<AnonConst>>,
+    pub body: Option<ConstItemRhs>,
     pub define_opaque: Option<ThinVec<(NodeId, Path)>>,
 }
 
+#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
+pub enum ConstItemRhs {
+    TypeConst(AnonConst),
+    Body(Box<Expr>),
+}
+
+impl ConstItemRhs {
+    pub fn span(&self) -> Span {
+        self.expr().span
+    }
+
+    pub fn expr(&self) -> &Expr {
+        match self {
+            ConstItemRhs::TypeConst(anon_const) => &anon_const.value,
+            ConstItemRhs::Body(expr) => expr,
+        }
+    }
+}
+
 // Adding a new variant? Please update `test_item` in `tests/ui/macros/stringify.rs`.
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub enum ItemKind {

compiler/rustc_ast/src/visit.rs

@@ -422,6 +422,7 @@ macro_rules! common_visitor_and_walkers {
             Closure,
             Const,
             ConstItem,
+            ConstItemRhs,
             Defaultness,
             Delegation,
             DelegationMac,

compiler/rustc_ast_lowering/src/item.rs

@@ -201,7 +201,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     |this| {
                         let ty = this
                             .lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::ConstTy));
-                        let body = this.lower_item_body_to_const_arg(body.as_deref());
+                        let body = this.lower_const_item_rhs(attrs, body.as_ref(), span);
                         (ty, body)
                     },
                 );
@@ -813,8 +813,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         let ty = this
                             .lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::ConstTy));
                         let body = body
-                            .as_deref()
-                            .map(|body| this.lower_item_body_to_const_arg(Some(body)));
+                            .as_ref()
+                            .map(|body| this.lower_const_item_rhs(attrs, Some(body), i.span));
                         hir::TraitItemKind::Const(ty, body)
                     },
                 );
@@ -1028,7 +1028,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         let ty = this
                             .lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::ConstTy));
                         this.lower_define_opaque(hir_id, &define_opaque);
-                        let body = this.lower_item_body_to_const_arg(body.as_deref());
+                        let body = this.lower_const_item_rhs(attrs, body.as_ref(), i.span);
                         hir::ImplItemKind::Const(ty, body)
                     },
                 ),

compiler/rustc_ast_lowering/src/lib.rs

@@ -2303,6 +2303,26 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.arena.alloc(hir::ConstArg { hir_id: self.next_id(), kind: ct_kind })
     }
 
+    fn lower_const_item_rhs(
+        &mut self,
+        attrs: &[hir::Attribute],
+        rhs: Option<&ConstItemRhs>,
+        span: Span,
+    ) -> hir::ConstItemRhs<'hir> {
+        match rhs {
+            Some(ConstItemRhs::TypeConst(anon)) => {
+                hir::ConstItemRhs::TypeConst(self.lower_item_body_to_const_arg(Some(anon)))
+            }
+            Some(ConstItemRhs::Body(body)) => {
+                hir::ConstItemRhs::Body(self.lower_const_body(span, Some(body)))
+            }
+            None if attr::contains_name(attrs, sym::type_const) => {
+                hir::ConstItemRhs::TypeConst(self.lower_item_body_to_const_arg(None))
+            }
+            None => hir::ConstItemRhs::Body(self.lower_const_body(span, None)),
+        }
+    }
+
     /// See [`hir::ConstArg`] for when to use this function vs
     /// [`Self::lower_anon_const_to_anon_const`].
     fn lower_item_body_to_const_arg(

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

@@ -221,7 +221,7 @@ impl<'a> State<'a> {
                     None,
                     generics,
                     ty,
-                    body.as_deref().map(|ct| &*ct.value),
+                    body.as_ref().map(|ct| ct.expr()),
                     &item.vis,
                     ast::Safety::Default,
                     *defaultness,
@@ -574,7 +574,7 @@ impl<'a> State<'a> {
                     None,
                     generics,
                     ty,
-                    body.as_deref().map(|ct| &*ct.value),
+                    body.as_ref().map(|ct| ct.expr()),
                     vis,
                     ast::Safety::Default,
                     *defaultness,

compiler/rustc_builtin_macros/src/alloc_error_handler.rs

@@ -42,7 +42,7 @@ pub(crate) fn expand(
 
     // Generate anonymous constant serving as container for the allocator methods.
     let const_ty = ecx.ty(sig_span, TyKind::Tup(ThinVec::new()));
-    let const_body = ecx.anon_const_block(ecx.block(span, stmts));
+    let const_body = ast::ConstItemRhs::Body(ecx.expr_block(ecx.block(span, stmts)));
     let const_item = ecx.item_const(span, Ident::new(kw::Underscore, span), const_ty, const_body);
     let const_item = if is_stmt {
         Annotatable::Stmt(Box::new(ecx.stmt_item(span, const_item)))

compiler/rustc_builtin_macros/src/global_allocator.rs

@@ -47,7 +47,7 @@ pub(crate) fn expand(
 
     // Generate anonymous constant serving as container for the allocator methods.
     let const_ty = ecx.ty(ty_span, TyKind::Tup(ThinVec::new()));
-    let const_body = ecx.anon_const_block(ecx.block(span, stmts));
+    let const_body = ast::ConstItemRhs::Body(ecx.expr_block(ecx.block(span, stmts)));
     let const_item = ecx.item_const(span, Ident::new(kw::Underscore, span), const_ty, const_body);
     let const_item = if is_stmt {
         Annotatable::Stmt(Box::new(ecx.stmt_item(span, const_item)))

compiler/rustc_builtin_macros/src/proc_macro_harness.rs

@@ -385,9 +385,9 @@ fn mk_decls(cx: &mut ExtCtxt<'_>, macros: &[ProcMacro]) -> Box<ast::Item> {
         cx.attr_nested_word(sym::allow, sym::deprecated, span),
     ]);
 
-    let block = cx.anon_const_block(
+    let block = ast::ConstItemRhs::Body(cx.expr_block(
         cx.block(span, thin_vec![cx.stmt_item(span, krate), cx.stmt_item(span, decls_static)]),
-    );
+    ));
 
     let anon_constant = cx.item_const(
         span,

compiler/rustc_builtin_macros/src/test.rs

@@ -289,9 +289,8 @@ pub(crate) fn expand_test_or_bench(
                     ty: cx.ty(sp, ast::TyKind::Path(None, test_path("TestDescAndFn"))),
                     define_opaque: None,
                     // test::TestDescAndFn {
-                    body: Some(Box::new(ast::AnonConst {
-                        id: ast::DUMMY_NODE_ID,
-                        value: cx.expr_struct(
+                    body: Some(ast::ConstItemRhs::Body(
+                        cx.expr_struct(
                             sp,
                             test_path("TestDescAndFn"),
                             thin_vec![
@@ -372,7 +371,7 @@ pub(crate) fn expand_test_or_bench(
                         field("testfn", test_fn), // }
                     ],
                         ), // }
-                    })),
+                    )),
                 }
                 .into(),
             ),

compiler/rustc_expand/src/build.rs

@@ -726,7 +726,7 @@ impl<'a> ExtCtxt<'a> {
         span: Span,
         ident: Ident,
         ty: Box<ast::Ty>,
-        body: Box<ast::AnonConst>,
+        body: ast::ConstItemRhs,
     ) -> Box<ast::Item> {
         let defaultness = ast::Defaultness::Final;
         self.item(