diff options
| -rw-r--r-- | clippy_lints/src/functions/must_use.rs | 58 | ||||
| -rw-r--r-- | tests/ui/must_use_unit.fixed | 6 | ||||
| -rw-r--r-- | tests/ui/must_use_unit.rs | 6 | ||||
| -rw-r--r-- | tests/ui/must_use_unit.stderr | 18 |
4 files changed, 75 insertions, 13 deletions
diff --git a/clippy_lints/src/functions/must_use.rs b/clippy_lints/src/functions/must_use.rs index 175d92d2d79..80813d3ccf1 100644 --- a/clippy_lints/src/functions/must_use.rs +++ b/clippy_lints/src/functions/must_use.rs @@ -29,7 +29,7 @@ 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, sig); + check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr, 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, @@ -51,7 +51,7 @@ pub(super) fn check_impl_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Imp 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, sig); + check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr, attrs, 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, @@ -74,7 +74,7 @@ pub(super) fn check_trait_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Tr 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, sig); + check_needless_must_use(cx, sig.decl, item.owner_id, item.span, fn_header_span, attr, 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) { @@ -92,6 +92,7 @@ pub(super) fn check_trait_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Tr } } +#[allow(clippy::too_many_arguments)] fn check_needless_must_use( cx: &LateContext<'_>, decl: &hir::FnDecl<'_>, @@ -99,21 +100,54 @@ fn check_needless_must_use( item_span: Span, fn_header_span: Span, attr: &Attribute, + attrs: &[Attribute], sig: &FnSig<'_>, ) { if in_external_macro(cx.sess(), item_span) { return; } if returns_unit(decl) { - span_lint_and_then( - cx, - MUST_USE_UNIT, - fn_header_span, - "this unit-returning function has a `#[must_use]` attribute", - |diag| { - diag.span_suggestion(attr.span, "remove the attribute", "", Applicability::MachineApplicable); - }, - ); + if attrs.len() == 1 { + span_lint_and_then( + cx, + MUST_USE_UNIT, + fn_header_span, + "this unit-returning function has a `#[must_use]` attribute", + |diag| { + diag.span_suggestion(attr.span, "remove the attribute", "", Applicability::MachineApplicable); + }, + ); + } else { + // When there are multiple attributes, it is not sufficient to simply make `must_use` empty, see + // issue #12320. + span_lint_and_then( + cx, + MUST_USE_UNIT, + fn_header_span, + "this unit-returning function has a `#[must_use]` attribute", + |diag| { + let mut attrs_without_must_use = attrs.to_vec(); + attrs_without_must_use.retain(|a| a.id != attr.id); + let sugg_str = attrs_without_must_use + .iter() + .map(|a| { + if a.value_str().is_none() { + return a.name_or_empty().to_string(); + } + format!("{} = \"{}\"", a.name_or_empty(), a.value_str().unwrap()) + }) + .collect::<Vec<_>>() + .join(", "); + + diag.span_suggestion( + attrs[0].span.with_hi(attrs[attrs.len() - 1].span.hi()), + "change these attributes to", + sugg_str, + Applicability::MachineApplicable, + ); + }, + ); + } } else if attr.value_str().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() { diff --git a/tests/ui/must_use_unit.fixed b/tests/ui/must_use_unit.fixed index f255cb66652..b92d9379c90 100644 --- a/tests/ui/must_use_unit.fixed +++ b/tests/ui/must_use_unit.fixed @@ -23,3 +23,9 @@ fn main() { fn foo() {} ); } + +#[cfg_attr(all(), deprecated)] +fn issue_12320() {} + +#[cfg_attr(all(), deprecated, doc = "foo")] +fn issue_12320_2() {} diff --git a/tests/ui/must_use_unit.rs b/tests/ui/must_use_unit.rs index 1305910ed0e..c77e7282750 100644 --- a/tests/ui/must_use_unit.rs +++ b/tests/ui/must_use_unit.rs @@ -26,3 +26,9 @@ fn main() { fn foo() {} ); } + +#[cfg_attr(all(), must_use, deprecated)] +fn issue_12320() {} + +#[cfg_attr(all(), deprecated, doc = "foo", must_use)] +fn issue_12320_2() {} diff --git a/tests/ui/must_use_unit.stderr b/tests/ui/must_use_unit.stderr index c2ee2edda7d..b435568deea 100644 --- a/tests/ui/must_use_unit.stderr +++ b/tests/ui/must_use_unit.stderr @@ -25,5 +25,21 @@ LL | #[must_use = "With note"] LL | pub fn must_use_with_note() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ -error: aborting due to 3 previous errors +error: this unit-returning function has a `#[must_use]` attribute + --> tests/ui/must_use_unit.rs:31:1 + | +LL | #[cfg_attr(all(), must_use, deprecated)] + | -------------------- help: change these attributes to: `deprecated` +LL | fn issue_12320() {} + | ^^^^^^^^^^^^^^^^ + +error: this unit-returning function has a `#[must_use]` attribute + --> tests/ui/must_use_unit.rs:34:1 + | +LL | #[cfg_attr(all(), deprecated, doc = "foo", must_use)] + | --------------------------------- help: change these attributes to: `deprecated, doc = "foo"` +LL | fn issue_12320_2() {} + | ^^^^^^^^^^^^^^^^^^ + +error: aborting due to 5 previous errors |