Port #[must_use] to new attribute parsing infrastructure

Signed-off-by: Jonathan Brouwer <jonathantbrouwer@gmail.com>

Author: JonathanBrouwer

clippy_lints/src/functions/must_use.rs

@@ -15,14 +15,17 @@ use clippy_utils::ty::is_must_use_ty;
 use clippy_utils::visitors::for_each_expr_without_closures;
 use clippy_utils::{return_ty, trait_ref_of_method};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
+use rustc_attr_data_structures::AttributeKind;
+use rustc_span::Symbol;
+use rustc_attr_data_structures::find_attr;
 
 use core::ops::ControlFlow;
 
 use super::{DOUBLE_MUST_USE, MUST_USE_CANDIDATE, MUST_USE_UNIT};
 
 pub(super) fn check_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
     let attrs = cx.tcx.hir_attrs(item.hir_id());
-    let attr = cx.tcx.get_attr(item.owner_id, sym::must_use);
+    let attr = find_attr!(cx.tcx.hir_attrs(item.hir_id()), AttributeKind::MustUse { span, reason } => (span, reason));
     if let hir::ItemKind::Fn {
         ref sig,
         body: ref body_id,
@@ -31,8 +34,8 @@ pub(super) fn check_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>
     {
         let is_public = cx.effective_visibilities.is_exported(item.owner_id.def_id);
         let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
-        if let Some(attr) = attr {
-            check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr, attrs, sig);
+        if let Some((attr_span, reason)) = attr {
+            check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, *attr_span, *reason, attrs, sig);
         } else if is_public && !is_proc_macro(attrs) && !attrs.iter().any(|a| a.has_name(sym::no_mangle)) {
             check_must_use_candidate(
                 cx,
@@ -52,9 +55,9 @@ pub(super) fn check_impl_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Imp
         let is_public = cx.effective_visibilities.is_exported(item.owner_id.def_id);
         let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
         let attrs = cx.tcx.hir_attrs(item.hir_id());
-        let attr = cx.tcx.get_attr(item.owner_id, sym::must_use);
-        if let Some(attr) = attr {
-            check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr, attrs, sig);
+        let attr = find_attr!(cx.tcx.hir_attrs(item.hir_id()), AttributeKind::MustUse { span, reason } => (span, reason));
+        if let Some((attr_span, reason)) = attr {
+            check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, *attr_span, *reason, attrs, sig);
         } else if is_public && !is_proc_macro(attrs) && trait_ref_of_method(cx, item.owner_id).is_none() {
             check_must_use_candidate(
                 cx,
@@ -75,9 +78,9 @@ pub(super) fn check_trait_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Tr
         let fn_header_span = item.span.with_hi(sig.decl.output.span().hi());
 
         let attrs = cx.tcx.hir_attrs(item.hir_id());
-        let attr = cx.tcx.get_attr(item.owner_id, sym::must_use);
-        if let Some(attr) = attr {
-            check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr, attrs, sig);
+        let attr = find_attr!(cx.tcx.hir_attrs(item.hir_id()), AttributeKind::MustUse { span, reason } => (span, reason));
+        if let Some((attr_span, reason)) = attr {
+            check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, *attr_span, *reason, attrs, sig);
         } else if let hir::TraitFn::Provided(eid) = *eid {
             let body = cx.tcx.hir_body(eid);
             if attr.is_none() && is_public && !is_proc_macro(attrs) {
@@ -103,7 +106,8 @@ fn check_needless_must_use(
     item_id: hir::OwnerId,
     item_span: Span,
     fn_header_span: Span,
-    attr: &Attribute,
+    attr_span: Span,
+    reason: Option<Symbol>,
     attrs: &[Attribute],
     sig: &FnSig<'_>,
 ) {
@@ -119,7 +123,7 @@ fn check_needless_must_use(
                 "this unit-returning function has a `#[must_use]` attribute",
                 |diag| {
                     diag.span_suggestion(
-                        attr.span(),
+                        attr_span,
                         "remove the attribute",
                         "",
                         Applicability::MachineApplicable,
@@ -137,11 +141,11 @@ fn check_needless_must_use(
                 MUST_USE_UNIT,
                 fn_header_span,
                 "this unit-returning function has a `#[must_use]` attribute",
-                Some(attr.span()),
+                Some(attr_span),
                 "remove `must_use`",
             );
         }
-    } else if attr.value_str().is_none() && is_must_use_ty(cx, return_ty(cx, item_id)) {
+    } else if reason.is_none() && is_must_use_ty(cx, return_ty(cx, item_id)) {
         // Ignore async functions unless Future::Output type is a must_use type
         if sig.header.is_async() {
             let infcx = cx.tcx.infer_ctxt().build(cx.typing_mode());

clippy_lints/src/return_self_not_must_use.rs

@@ -6,7 +6,9 @@ use rustc_hir::intravisit::FnKind;
 use rustc_hir::{Body, FnDecl, OwnerId, TraitItem, TraitItemKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::declare_lint_pass;
-use rustc_span::{Span, sym};
+use rustc_span::{Span};
+use rustc_attr_data_structures::AttributeKind;
+use rustc_attr_data_structures::find_attr;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -74,7 +76,10 @@ fn check_method(cx: &LateContext<'_>, decl: &FnDecl<'_>, fn_def: LocalDefId, spa
         // We only show this warning for public exported methods.
         && cx.effective_visibilities.is_exported(fn_def)
         // We don't want to emit this lint if the `#[must_use]` attribute is already there.
-        && !cx.tcx.hir_attrs(owner_id.into()).iter().any(|attr| attr.has_name(sym::must_use))
+        && !find_attr!(
+            cx.tcx.hir_attrs(owner_id.into()),
+            AttributeKind::MustUse { .. }
+        )
         && cx.tcx.visibility(fn_def.to_def_id()).is_public()
         && let ret_ty = return_ty(cx, owner_id)
         && let self_arg = nth_arg(cx, owner_id, 0)

clippy_utils/src/lib.rs

@@ -1886,7 +1886,10 @@ pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
         _ => None,
     };
 
-    did.is_some_and(|did| cx.tcx.has_attr(did, sym::must_use))
+    did.is_some_and(|did| find_attr!(
+            cx.tcx.get_all_attrs(did),
+            AttributeKind::MustUse { ..}
+        ))
 }
 
 /// Checks if a function's body represents the identity function. Looks for bodies of the form:

clippy_utils/src/ty/mod.rs

@@ -31,6 +31,8 @@ use rustc_trait_selection::traits::{Obligation, ObligationCause};
 use std::assert_matches::debug_assert_matches;
 use std::collections::hash_map::Entry;
 use std::iter;
+use rustc_attr_data_structures::find_attr;
+use rustc_attr_data_structures::AttributeKind;
 
 use crate::path_res;
 use crate::paths::{PathNS, lookup_path_str};
@@ -326,8 +328,14 @@ pub fn has_drop<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
 // Returns whether the type has #[must_use] attribute
 pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
     match ty.kind() {
-        ty::Adt(adt, _) => cx.tcx.has_attr(adt.did(), sym::must_use),
-        ty::Foreign(did) => cx.tcx.has_attr(*did, sym::must_use),
+        ty::Adt(adt, _) => find_attr!(
+            cx.tcx.get_all_attrs(adt.did()),
+            AttributeKind::MustUse { ..}
+        ),
+        ty::Foreign(did) => find_attr!(
+            cx.tcx.get_all_attrs(*did),
+            AttributeKind::MustUse { ..}
+        ),
         ty::Slice(ty) | ty::Array(ty, _) | ty::RawPtr(ty, _) | ty::Ref(_, ty, _) => {
             // for the Array case we don't need to care for the len == 0 case
             // because we don't want to lint functions returning empty arrays
@@ -337,7 +345,7 @@ pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
         ty::Alias(ty::Opaque, AliasTy { def_id, .. }) => {
             for (predicate, _) in cx.tcx.explicit_item_self_bounds(def_id).skip_binder() {
                 if let ty::ClauseKind::Trait(trait_predicate) = predicate.kind().skip_binder()
-                    && cx.tcx.has_attr(trait_predicate.trait_ref.def_id, sym::must_use)
+                    && find_attr!(cx.tcx.get_all_attrs(trait_predicate.trait_ref.def_id), AttributeKind::MustUse { ..})
                 {
                     return true;
                 }
@@ -347,7 +355,7 @@ pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
         ty::Dynamic(binder, _, _) => {
             for predicate in *binder {
                 if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder()
-                    && cx.tcx.has_attr(trait_ref.def_id, sym::must_use)
+                    && find_attr!(cx.tcx.get_all_attrs(trait_ref.def_id), AttributeKind::MustUse { ..})
                 {
                     return true;
                 }