diff --git a/clippy_lints/src/functions/must_use.rs b/clippy_lints/src/functions/must_use.rs index 56acd31b1d2..ab68d7a3726 100644 --- a/clippy_lints/src/functions/must_use.rs +++ b/clippy_lints/src/functions/must_use.rs @@ -1,3 +1,4 @@ +use hir::FnSig; use rustc_ast::ast::Attribute; use rustc_errors::Applicability; use rustc_hir::def_id::DefIdSet; @@ -23,12 +24,11 @@ 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); - if let hir::ItemKind::Fn(ref sig, _generics, ref body_id) = item.kind && !sig.header.is_async() /* (#10486) */ { - + if let hir::ItemKind::Fn(ref sig, _generics, ref body_id) = item.kind { 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); + check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr, sig); } else if is_public && !is_proc_macro(attrs) && !attrs.iter().any(|a| a.has_name(sym::no_mangle)) { check_must_use_candidate( cx, @@ -44,13 +44,13 @@ pub(super) fn check_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_> } pub(super) fn check_impl_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::ImplItem<'_>) { - if let hir::ImplItemKind::Fn(ref sig, ref body_id) = item.kind && !sig.header.is_async() /* (#10486) */ { + if let hir::ImplItemKind::Fn(ref sig, ref body_id) = item.kind { 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); + check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr, sig); } else if is_public && !is_proc_macro(attrs) && trait_ref_of_method(cx, item.owner_id.def_id).is_none() { check_must_use_candidate( cx, @@ -66,14 +66,14 @@ pub(super) fn check_impl_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Imp } pub(super) fn check_trait_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::TraitItem<'_>) { - if let hir::TraitItemKind::Fn(ref sig, ref eid) = item.kind && !sig.header.is_async() /* (#10486) */ { + if let hir::TraitItemKind::Fn(ref sig, ref eid) = item.kind { 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); + check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr, 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) { @@ -98,6 +98,7 @@ fn check_needless_must_use( item_span: Span, fn_header_span: Span, attr: &Attribute, + sig: &FnSig<'_>, ) { if in_external_macro(cx.sess(), item_span) { return; @@ -112,7 +113,7 @@ fn check_needless_must_use( diag.span_suggestion(attr.span, "remove the attribute", "", Applicability::MachineApplicable); }, ); - } else if attr.value_str().is_none() && is_must_use_ty(cx, return_ty(cx, item_id)) { + } else if attr.value_str().is_none() && is_must_use_ty(cx, return_ty(cx, item_id)) && !sig.header.is_async() { span_lint_and_help( cx, DOUBLE_MUST_USE, diff --git a/tests/ui/double_must_use.rs b/tests/ui/double_must_use.rs index a4cd8630de5..26a387b3cf0 100644 --- a/tests/ui/double_must_use.rs +++ b/tests/ui/double_must_use.rs @@ -27,6 +27,11 @@ async fn async_must_use() -> usize { unimplemented!(); } +#[must_use] +async fn async_must_use_result() -> Result<(), ()> { + Ok(()) +} + fn main() { must_use_result(); must_use_tuple();