diff options
| -rw-r--r-- | compiler/rustc_ast_lowering/src/expr.rs | 14 | ||||
| -rw-r--r-- | compiler/rustc_feature/src/builtin_attrs.rs | 6 | ||||
| -rw-r--r-- | compiler/rustc_span/src/symbol.rs | 1 | ||||
| -rw-r--r-- | src/test/ui/type/ascription/issue-47666.stderr | 2 |
4 files changed, 21 insertions, 2 deletions
diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs index 3aff04f78fb..04d88282862 100644 --- a/compiler/rustc_ast_lowering/src/expr.rs +++ b/compiler/rustc_ast_lowering/src/expr.rs @@ -41,7 +41,19 @@ impl<'hir> LoweringContext<'_, 'hir> { } ExprKind::Tup(ref elts) => hir::ExprKind::Tup(self.lower_exprs(elts)), ExprKind::Call(ref f, ref args) => { - if let Some(legacy_args) = self.resolver.legacy_const_generic_args(f) { + if e.attrs.get(0).map_or(false, |a| a.has_name(sym::rustc_box)) { + if let [inner] = &args[..] { + hir::ExprKind::Box(self.lower_expr(&inner)) + } else { + self.sess + .struct_span_err( + e.span, + "rustc_box requires precisely one argument", + ) + .emit(); + hir::ExprKind::Err + } + } else if let Some(legacy_args) = self.resolver.legacy_const_generic_args(f) { self.lower_legacy_const_generics((**f).clone(), args.clone(), &legacy_args) } else { let f = self.lower_expr(f); diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs index 8155e65a6db..5eb2be97f8b 100644 --- a/compiler/rustc_feature/src/builtin_attrs.rs +++ b/compiler/rustc_feature/src/builtin_attrs.rs @@ -675,6 +675,12 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[ "#[rustc_has_incoherent_inherent_impls] allows the addition of incoherent inherent impls for \ the given type by annotating all impl items with #[rustc_allow_incoherent_impl]." ), + rustc_attr!( + rustc_box, AttributeType::Normal, template!(Word), ErrorFollowing, + "#[rustc_box] allows creating boxes \ + and it is only intended to be used in `alloc`." + ), + BuiltinAttribute { name: sym::rustc_diagnostic_item, // FIXME: This can be `true` once we always use `tcx.is_diagnostic_item`. diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index 16162f1cc89..1954cdc0bff 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -1173,6 +1173,7 @@ symbols! { rustc_allow_const_fn_unstable, rustc_allow_incoherent_impl, rustc_attrs, + rustc_box, rustc_builtin_macro, rustc_capture_analysis, rustc_clean, diff --git a/src/test/ui/type/ascription/issue-47666.stderr b/src/test/ui/type/ascription/issue-47666.stderr index 59b35292726..b59a73af9f9 100644 --- a/src/test/ui/type/ascription/issue-47666.stderr +++ b/src/test/ui/type/ascription/issue-47666.stderr @@ -1,4 +1,4 @@ -error: expected type, found `<[_]>::into_vec(box [0, 1])` +error: expected type, found `<[_]>::into_vec(#[rustc_box] ::alloc::boxed::Box::new([0, 1]))` --> $DIR/issue-47666.rs:3:25 | LL | let _ = Option:Some(vec![0, 1]); |