Port #[rustc_as_ptr] to the new attribute system

Author: GrigorenkoPV

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -158,6 +158,9 @@ pub enum AttributeKind {
     /// Represents `#[allow_internal_unstable]`.
     AllowInternalUnstable(ThinVec<(Symbol, Span)>),
 
+    /// Represents `#[rustc_as_ptr]` (used by the `dangling_pointers_from_temporaries` lint).
+    AsPtr(Span),
+
     /// Represents `#[rustc_default_body_unstable]`.
     BodyStability {
         stability: DefaultBodyStability,

compiler/rustc_attr_parsing/src/attributes/lint_helpers.rs

@@ -0,0 +1,21 @@
+use rustc_attr_data_structures::AttributeKind;
+use rustc_span::{Symbol, sym};
+
+use crate::attributes::{AttributeOrder, OnDuplicate, SingleAttributeParser};
+use crate::context::{AcceptContext, Stage};
+use crate::parser::ArgParser;
+
+pub(crate) struct AsPtrParser;
+
+impl<S: Stage> SingleAttributeParser<S> for AsPtrParser {
+    const PATH: &[Symbol] = &[sym::rustc_as_ptr];
+
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, _args: &ArgParser<'_>) -> Option<AttributeKind> {
+        // FIXME: check that there's no args (this is currently checked elsewhere)
+        Some(AttributeKind::AsPtr(cx.attr_span))
+    }
+}

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -29,6 +29,7 @@ pub(crate) mod allow_unstable;
 pub(crate) mod cfg;
 pub(crate) mod confusables;
 pub(crate) mod deprecation;
+pub(crate) mod lint_helpers;
 pub(crate) mod repr;
 pub(crate) mod stability;
 pub(crate) mod transparency;

compiler/rustc_attr_parsing/src/context.rs

@@ -18,6 +18,7 @@ use rustc_span::{DUMMY_SP, ErrorGuaranteed, Span, Symbol, sym};
 use crate::attributes::allow_unstable::{AllowConstFnUnstableParser, AllowInternalUnstableParser};
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::deprecation::DeprecationParser;
+use crate::attributes::lint_helpers::AsPtrParser;
 use crate::attributes::repr::ReprParser;
 use crate::attributes::stability::{
     BodyStabilityParser, ConstStabilityIndirectParser, ConstStabilityParser, StabilityParser,
@@ -102,6 +103,7 @@ attribute_parsers!(
         // tidy-alphabetical-end
 
         // tidy-alphabetical-start
+        Single<AsPtrParser>,
         Single<ConstStabilityIndirectParser>,
         Single<DeprecationParser>,
         Single<TransparencyParser>,

compiler/rustc_lint/src/dangling.rs

@@ -1,4 +1,5 @@
 use rustc_ast::visit::{visit_opt, walk_list};
+use rustc_attr_data_structures::{AttributeKind, find_attr};
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::{FnKind, Visitor, walk_expr};
 use rustc_hir::{Block, Body, Expr, ExprKind, FnDecl, LangItem};
@@ -133,7 +134,7 @@ fn lint_expr(cx: &LateContext<'_>, expr: &Expr<'_>) {
         && let ty = cx.typeck_results().expr_ty(receiver)
         && owns_allocation(cx.tcx, ty)
         && let Some(fn_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id)
-        && cx.tcx.has_attr(fn_id, sym::rustc_as_ptr)
+        && find_attr!(cx.tcx.get_all_attrs(fn_id), AttributeKind::AsPtr(_))
     {
         // FIXME: use `emit_node_lint` when `#[primary_span]` is added.
         cx.tcx.emit_node_span_lint(

compiler/rustc_passes/src/check_attr.rs

@@ -147,6 +147,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::ConstStabilityIndirect
                     | AttributeKind::MacroTransparency(_),
                 ) => { /* do nothing  */ }
+                Attribute::Parsed(AttributeKind::AsPtr(attr_span)) => {
+                    self.check_applied_to_fn_or_method(hir_id, *attr_span, span, target)
+                }
                 Attribute::Unparsed(_) => {
                     match attr.path().as_slice() {
                         [sym::diagnostic, sym::do_not_recommend, ..] => {
@@ -188,26 +191,23 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             self.check_rustc_std_internal_symbol(attr, span, target)
                         }
                         [sym::naked, ..] => self.check_naked(hir_id, attr, span, target, attrs),
-                        [sym::rustc_as_ptr, ..] => {
-                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
-                        }
                         [sym::rustc_no_implicit_autorefs, ..] => {
-                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
+                            self.check_applied_to_fn_or_method(hir_id, attr.span(), span, target)
                         }
                         [sym::rustc_never_returns_null_ptr, ..] => {
-                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
+                            self.check_applied_to_fn_or_method(hir_id, attr.span(), span, target)
                         }
                         [sym::rustc_legacy_const_generics, ..] => {
                             self.check_rustc_legacy_const_generics(hir_id, attr, span, target, item)
                         }
                         [sym::rustc_lint_query_instability, ..] => {
-                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
+                            self.check_applied_to_fn_or_method(hir_id, attr.span(), span, target)
                         }
                         [sym::rustc_lint_untracked_query_information, ..] => {
-                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
+                            self.check_applied_to_fn_or_method(hir_id, attr.span(), span, target)
                         }
                         [sym::rustc_lint_diagnostics, ..] => {
-                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
+                            self.check_applied_to_fn_or_method(hir_id, attr.span(), span, target)
                         }
                         [sym::rustc_lint_opt_ty, ..] => self.check_rustc_lint_opt_ty(attr, span, target),
                         [sym::rustc_lint_opt_deny_field_access, ..] => {
@@ -1825,15 +1825,15 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     fn check_applied_to_fn_or_method(
         &self,
         hir_id: HirId,
-        attr: &Attribute,
-        span: Span,
+        attr_span: Span,
+        defn_span: Span,
         target: Target,
     ) {
         let is_function = matches!(target, Target::Fn | Target::Method(..));
         if !is_function {
             self.dcx().emit_err(errors::AttrShouldBeAppliedToFn {
-                attr_span: attr.span(),
-                defn_span: span,
+                attr_span,
+                defn_span,
                 on_crate: hir_id == CRATE_HIR_ID,
             });
         }