From d84576955713d223c0c4752dab9111085033c78b Mon Sep 17 00:00:00 2001 From: clubby789 Date: Mon, 27 Feb 2023 01:32:07 +0000 Subject: [PATCH] Restrict `#[rustc_box]` to `Box::new` calls --- compiler/rustc_ast_lowering/locales/en-US.ftl | 3 -- compiler/rustc_ast_lowering/src/errors.rs | 7 ---- compiler/rustc_ast_lowering/src/expr.rs | 12 ++----- compiler/rustc_mir_build/locales/en-US.ftl | 6 ++++ compiler/rustc_mir_build/src/errors.rs | 19 +++++++++++ compiler/rustc_mir_build/src/thir/cx/expr.rs | 32 ++++++++++++++++- src/tools/clippy/clippy_utils/src/higher.rs | 13 +++---- tests/ui/attributes/rustc-box.rs | 18 ++++++++++ tests/ui/attributes/rustc-box.stderr | 34 +++++++++++++++++++ 9 files changed, 115 insertions(+), 29 deletions(-) create mode 100644 tests/ui/attributes/rustc-box.rs create mode 100644 tests/ui/attributes/rustc-box.stderr diff --git a/compiler/rustc_ast_lowering/locales/en-US.ftl b/compiler/rustc_ast_lowering/locales/en-US.ftl index a2837deafdec4..3ccd84398ec27 100644 --- a/compiler/rustc_ast_lowering/locales/en-US.ftl +++ b/compiler/rustc_ast_lowering/locales/en-US.ftl @@ -22,9 +22,6 @@ ast_lowering_misplaced_impl_trait = ast_lowering_misplaced_assoc_ty_binding = associated type bounds are only allowed in where clauses and function signatures, not in {$position} -ast_lowering_rustc_box_attribute_error = - #[rustc_box] requires precisely one argument and no other attributes are allowed - ast_lowering_underscore_expr_lhs_assign = in expressions, `_` can only be used on the left-hand side of an assignment .label = `_` not allowed here diff --git a/compiler/rustc_ast_lowering/src/errors.rs b/compiler/rustc_ast_lowering/src/errors.rs index def74c2adeee9..5e6b6050bc0ea 100644 --- a/compiler/rustc_ast_lowering/src/errors.rs +++ b/compiler/rustc_ast_lowering/src/errors.rs @@ -87,13 +87,6 @@ pub struct MisplacedAssocTyBinding<'a> { pub position: DiagnosticArgFromDisplay<'a>, } -#[derive(Diagnostic, Clone, Copy)] -#[diag(ast_lowering_rustc_box_attribute_error)] -pub struct RustcBoxAttributeError { - #[primary_span] - pub span: Span, -} - #[derive(Diagnostic, Clone, Copy)] #[diag(ast_lowering_underscore_expr_lhs_assign)] pub struct UnderscoreExprLhsAssign { diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs index d4fafe38638a4..ffb30b1b39127 100644 --- a/compiler/rustc_ast_lowering/src/expr.rs +++ b/compiler/rustc_ast_lowering/src/expr.rs @@ -2,7 +2,7 @@ use super::errors::{ AsyncGeneratorsNotSupported, AsyncNonMoveClosureNotSupported, AwaitOnlyInAsyncFnAndBlocks, BaseExpressionDoubleDot, ClosureCannotBeStatic, FunctionalRecordUpdateDestructuringAssignemnt, GeneratorTooManyParameters, InclusiveRangeWithNoEnd, NotSupportedForLifetimeBinderAsyncClosure, - RustcBoxAttributeError, UnderscoreExprLhsAssign, + UnderscoreExprLhsAssign, }; use super::ResolverAstLoweringExt; use super::{ImplTraitContext, LoweringContext, ParamMode, ParenthesizedGenericArgs}; @@ -83,15 +83,7 @@ impl<'hir> LoweringContext<'_, 'hir> { } ExprKind::Tup(elts) => hir::ExprKind::Tup(self.lower_exprs(elts)), ExprKind::Call(f, args) => { - if e.attrs.get(0).map_or(false, |a| a.has_name(sym::rustc_box)) { - if let [inner] = &args[..] && e.attrs.len() == 1 { - let kind = hir::ExprKind::Box(self.lower_expr(&inner)); - return hir::Expr { hir_id, kind, span: self.lower_span(e.span) }; - } else { - let guar = self.tcx.sess.emit_err(RustcBoxAttributeError { span: e.span }); - hir::ExprKind::Err(guar) - } - } else if let Some(legacy_args) = self.resolver.legacy_const_generic_args(f) { + 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_mir_build/locales/en-US.ftl b/compiler/rustc_mir_build/locales/en-US.ftl index f9bda721df34d..93e7fb330e093 100644 --- a/compiler/rustc_mir_build/locales/en-US.ftl +++ b/compiler/rustc_mir_build/locales/en-US.ftl @@ -374,3 +374,9 @@ mir_build_suggest_let_else = you might want to use `let else` to handle the {$co } matched mir_build_suggest_attempted_int_lit = alternatively, you could prepend the pattern with an underscore to define a new named variable; identifiers cannot begin with digits + + +mir_build_rustc_box_attribute_error = `#[rustc_box]` attribute used incorrectly + .attributes = no other attributes may be applied + .not_box = `#[rustc_box]` may only be applied to a `Box::new()` call + .missing_box = `#[rustc_box]` requires the `owned_box` lang item diff --git a/compiler/rustc_mir_build/src/errors.rs b/compiler/rustc_mir_build/src/errors.rs index c1f6b8b59ce59..dc4d2276e4aab 100644 --- a/compiler/rustc_mir_build/src/errors.rs +++ b/compiler/rustc_mir_build/src/errors.rs @@ -888,3 +888,22 @@ pub enum MiscPatternSuggestion { start_span: Span, }, } + +#[derive(Diagnostic)] +#[diag(mir_build_rustc_box_attribute_error)] +pub struct RustcBoxAttributeError { + #[primary_span] + pub span: Span, + #[subdiagnostic] + pub reason: RustcBoxAttrReason, +} + +#[derive(Subdiagnostic)] +pub enum RustcBoxAttrReason { + #[note(mir_build_attributes)] + Attributes, + #[note(mir_build_not_box)] + NotBoxNew, + #[note(mir_build_missing_box)] + MissingBox, +} diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs index ae203233bd568..f3fa0c37be985 100644 --- a/compiler/rustc_mir_build/src/thir/cx/expr.rs +++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs @@ -1,3 +1,4 @@ +use crate::errors; use crate::thir::cx::region::Scope; use crate::thir::cx::Cx; use crate::thir::util::UserAnnotatedTyHelpers; @@ -18,7 +19,7 @@ use rustc_middle::ty::subst::InternalSubsts; use rustc_middle::ty::{ self, AdtKind, InlineConstSubsts, InlineConstSubstsParts, ScalarInt, Ty, UpvarSubsts, UserType, }; -use rustc_span::Span; +use rustc_span::{sym, Span}; use rustc_target::abi::VariantIdx; impl<'tcx> Cx<'tcx> { @@ -262,6 +263,7 @@ impl<'tcx> Cx<'tcx> { } } + #[instrument(level = "debug", skip(self), ret)] fn make_mirror_unadjusted(&mut self, expr: &'tcx hir::Expr<'tcx>) -> Expr<'tcx> { let tcx = self.tcx; let expr_ty = self.typeck_results().expr_ty(expr); @@ -322,6 +324,34 @@ impl<'tcx> Cx<'tcx> { fn_span: expr.span, } } else { + let attrs = tcx.hir().attrs(expr.hir_id); + if attrs.iter().any(|a| a.name_or_empty() == sym::rustc_box) { + if attrs.len() != 1 { + tcx.sess.emit_err(errors::RustcBoxAttributeError { + span: attrs[0].span, + reason: errors::RustcBoxAttrReason::Attributes, + }); + } else if let Some(box_item) = tcx.lang_items().owned_box() { + if let hir::ExprKind::Path(hir::QPath::TypeRelative(ty, fn_path)) = fun.kind + && let hir::TyKind::Path(hir::QPath::Resolved(_, path)) = ty.kind + && path.res.opt_def_id().map_or(false, |did| did == box_item) + && fn_path.ident.name == sym::new + && let [value] = args + { + return Expr { temp_lifetime, ty: expr_ty, span: expr.span, kind: ExprKind::Box { value: self.mirror_expr(value) } } + } else { + tcx.sess.emit_err(errors::RustcBoxAttributeError { + span: expr.span, + reason: errors::RustcBoxAttrReason::NotBoxNew + }); + } + } else { + tcx.sess.emit_err(errors::RustcBoxAttributeError { + span: attrs[0].span, + reason: errors::RustcBoxAttrReason::MissingBox, + }); + } + } let adt_data = if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = fun.kind { // Tuple-like ADTs are represented as ExprKind::Call. We convert them here. diff --git a/src/tools/clippy/clippy_utils/src/higher.rs b/src/tools/clippy/clippy_utils/src/higher.rs index 4604ae5c2c7f0..50bef3709309d 100644 --- a/src/tools/clippy/clippy_utils/src/higher.rs +++ b/src/tools/clippy/clippy_utils/src/higher.rs @@ -287,15 +287,12 @@ impl<'a> VecArgs<'a> { Some(VecArgs::Repeat(&args[0], &args[1])) } else if match_def_path(cx, fun_def_id, &paths::SLICE_INTO_VEC) && args.len() == 1 { // `vec![a, b, c]` case - if_chain! { - if let hir::ExprKind::Box(boxed) = args[0].kind; - if let hir::ExprKind::Array(args) = boxed.kind; - then { - return Some(VecArgs::Vec(args)); - } + if let hir::ExprKind::Call(_, [arg]) = &args[0].kind + && let hir::ExprKind::Array(args) = arg.kind { + Some(VecArgs::Vec(args)) + } else { + None } - - None } else if match_def_path(cx, fun_def_id, &paths::VEC_NEW) && args.is_empty() { Some(VecArgs::Vec(&[])) } else { diff --git a/tests/ui/attributes/rustc-box.rs b/tests/ui/attributes/rustc-box.rs new file mode 100644 index 0000000000000..b3726fb38671b --- /dev/null +++ b/tests/ui/attributes/rustc-box.rs @@ -0,0 +1,18 @@ +#![feature(rustc_attrs, stmt_expr_attributes)] + +fn foo(_: u32, _: u32) {} +fn bar(_: u32) {} + +fn main() { + #[rustc_box] + Box::new(1); // OK + #[rustc_box] + Box::pin(1); //~ ERROR `#[rustc_box]` attribute used incorrectly + #[rustc_box] + foo(1, 1); //~ ERROR `#[rustc_box]` attribute used incorrectly + #[rustc_box] + bar(1); //~ ERROR `#[rustc_box]` attribute used incorrectly + #[rustc_box] //~ ERROR `#[rustc_box]` attribute used incorrectly + #[rustfmt::skip] + Box::new(1); +} diff --git a/tests/ui/attributes/rustc-box.stderr b/tests/ui/attributes/rustc-box.stderr new file mode 100644 index 0000000000000..073a18c7d58ec --- /dev/null +++ b/tests/ui/attributes/rustc-box.stderr @@ -0,0 +1,34 @@ +error: `#[rustc_box]` attribute used incorrectly + --> $DIR/rustc-box.rs:10:5 + | +LL | Box::pin(1); + | ^^^^^^^^^^^ + | + = note: `#[rustc_box]` may only be applied to a `Box::new()` call + +error: `#[rustc_box]` attribute used incorrectly + --> $DIR/rustc-box.rs:12:5 + | +LL | foo(1, 1); + | ^^^^^^^^^ + | + = note: `#[rustc_box]` may only be applied to a `Box::new()` call + +error: `#[rustc_box]` attribute used incorrectly + --> $DIR/rustc-box.rs:14:5 + | +LL | bar(1); + | ^^^^^^ + | + = note: `#[rustc_box]` may only be applied to a `Box::new()` call + +error: `#[rustc_box]` attribute used incorrectly + --> $DIR/rustc-box.rs:15:5 + | +LL | #[rustc_box] + | ^^^^^^^^^^^^ + | + = note: no other attributes may be applied + +error: aborting due to 4 previous errors +