Port #[rustc_pass_by_value] to the new attribute system

Author: GrigorenkoPV

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -284,6 +284,9 @@ pub enum AttributeKind {
     /// Represents `#[optimize(size|speed)]`
     Optimize(OptimizeAttr, Span),
 
+    /// Represents `#[rustc_pass_by_value]` (used by the `rustc_pass_by_value` lint).
+    PassByValue(Span),
+
     /// Represents `#[rustc_pub_transparent]` (used by the `repr_transparent_external_private_fields` lint).
     PubTransparent(Span),
 

compiler/rustc_attr_data_structures/src/encode_cross_crate.rs

@@ -36,6 +36,7 @@ impl AttributeKind {
             Naked(..) => No,
             NoMangle(..) => No,
             Optimize(..) => No,
+            PassByValue(..) => Yes,
             PubTransparent(..) => Yes,
             Repr(..) => No,
             RustcLayoutScalarValidRangeEnd(..) => Yes,

compiler/rustc_attr_parsing/src/attributes/lint_helpers.rs

@@ -17,3 +17,10 @@ impl<S: Stage> NoArgsAttributeParser<S> for PubTransparentParser {
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const CREATE: fn(Span) -> AttributeKind = AttributeKind::PubTransparent;
 }
+
+pub(crate) struct PassByValueParser;
+impl<S: Stage> NoArgsAttributeParser<S> for PassByValueParser {
+    const PATH: &[Symbol] = &[sym::rustc_pass_by_value];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::PassByValue;
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -23,7 +23,7 @@ use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::deprecation::DeprecationParser;
 use crate::attributes::inline::{InlineParser, RustcForceInlineParser};
 use crate::attributes::link_attrs::{LinkNameParser, LinkSectionParser};
-use crate::attributes::lint_helpers::{AsPtrParser, PubTransparentParser};
+use crate::attributes::lint_helpers::{AsPtrParser, PassByValueParser, PubTransparentParser};
 use crate::attributes::loop_match::{ConstContinueParser, LoopMatchParser};
 use crate::attributes::must_use::MustUseParser;
 use crate::attributes::repr::{AlignParser, ReprParser};
@@ -142,6 +142,7 @@ attribute_parsers!(
         Single<WithoutArgs<LoopMatchParser>>,
         Single<WithoutArgs<MayDangleParser>>,
         Single<WithoutArgs<NoMangleParser>>,
+        Single<WithoutArgs<PassByValueParser>>,
         Single<WithoutArgs<PubTransparentParser>>,
         Single<WithoutArgs<TrackCallerParser>>,
         // tidy-alphabetical-end

compiler/rustc_lint/src/pass_by_value.rs

@@ -1,8 +1,8 @@
+use rustc_attr_data_structures::{AttributeKind, find_attr};
 use rustc_hir::def::Res;
 use rustc_hir::{self as hir, AmbigArg, GenericArg, PathSegment, QPath, TyKind};
 use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::sym;
 
 use crate::lints::PassByValueDiag;
 use crate::{LateContext, LateLintPass, LintContext};
@@ -45,14 +45,16 @@ impl<'tcx> LateLintPass<'tcx> for PassByValue {
 fn path_for_pass_by_value(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> Option<String> {
     if let TyKind::Path(QPath::Resolved(_, path)) = &ty.kind {
         match path.res {
-            Res::Def(_, def_id) if cx.tcx.has_attr(def_id, sym::rustc_pass_by_value) => {
+            Res::Def(_, def_id)
+                if find_attr!(cx.tcx.get_all_attrs(def_id), AttributeKind::PassByValue(_)) =>
+            {
                 let name = cx.tcx.item_ident(def_id);
                 let path_segment = path.segments.last().unwrap();
                 return Some(format!("{}{}", name, gen_args(cx, path_segment)));
             }
             Res::SelfTyAlias { alias_to: did, is_trait_impl: false, .. } => {
                 if let ty::Adt(adt, args) = cx.tcx.type_of(did).instantiate_identity().kind() {
-                    if cx.tcx.has_attr(adt.did(), sym::rustc_pass_by_value) {
+                    if find_attr!(cx.tcx.get_all_attrs(adt.did()), AttributeKind::PassByValue(_)) {
                         return Some(cx.tcx.def_path_str_with_args(adt.did(), args));
                     }
                 }

compiler/rustc_parse/src/validate_attr.rs

@@ -293,6 +293,7 @@ fn emit_malformed_attribute(
             | sym::rustc_force_inline
             | sym::rustc_confusables
             | sym::rustc_skip_during_method_dispatch
+            | sym::rustc_pass_by_value
             | sym::repr
             | sym::align
             | sym::deprecated

compiler/rustc_passes/src/check_attr.rs

@@ -213,6 +213,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 Attribute::Parsed(AttributeKind::Used { span: attr_span, .. }) => {
                     self.check_used(*attr_span, target, span);
                 }
+                &Attribute::Parsed(AttributeKind::PassByValue(attr_span)) => {
+                    self.check_pass_by_value(attr_span, span, target)
+                }
                 Attribute::Unparsed(attr_item) => {
                     style = Some(attr_item.style);
                     match attr.path().as_slice() {
@@ -275,7 +278,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         | [sym::const_trait, ..] => self.check_must_be_applied_to_trait(attr.span(), span, target),
                         [sym::collapse_debuginfo, ..] => self.check_collapse_debuginfo(attr, span, target),
                         [sym::must_not_suspend, ..] => self.check_must_not_suspend(attr, span, target),
-                        [sym::rustc_pass_by_value, ..] => self.check_pass_by_value(attr, span, target),
                         [sym::rustc_allow_incoherent_impl, ..] => {
                             self.check_allow_incoherent_impl(attr, span, target)
                         }
@@ -1438,11 +1440,11 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     }
 
     /// Warns against some misuses of `#[pass_by_value]`
-    fn check_pass_by_value(&self, attr: &Attribute, span: Span, target: Target) {
+    fn check_pass_by_value(&self, attr_span: Span, span: Span, target: Target) {
         match target {
             Target::Struct | Target::Enum | Target::TyAlias => {}
             _ => {
-                self.dcx().emit_err(errors::PassByValue { attr_span: attr.span(), span });
+                self.dcx().emit_err(errors::PassByValue { attr_span, span });
             }
         }
     }