diff options
Diffstat (limited to 'compiler/rustc_lint/src/unused.rs')
| -rw-r--r-- | compiler/rustc_lint/src/unused.rs | 87 |
1 files changed, 43 insertions, 44 deletions
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs index 3a92f5806..28cc63198 100644 --- a/compiler/rustc_lint/src/unused.rs +++ b/compiler/rustc_lint/src/unused.rs @@ -12,9 +12,9 @@ use rustc_errors::{pluralize, MultiSpan}; use rustc_hir as hir; use rustc_hir::def::{DefKind, Res}; use rustc_hir::def_id::DefId; -use rustc_infer::traits::util::elaborate_predicates_with_span; +use rustc_infer::traits::util::elaborate; use rustc_middle::ty::adjustment; -use rustc_middle::ty::{self, DefIdTree, Ty}; +use rustc_middle::ty::{self, Ty}; use rustc_span::symbol::Symbol; use rustc_span::symbol::{kw, sym}; use rustc_span::{BytePos, Span}; @@ -103,8 +103,10 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults { && let ty = cx.typeck_results().expr_ty(&await_expr) && let ty::Alias(ty::Opaque, ty::AliasTy { def_id: future_def_id, .. }) = ty.kind() && cx.tcx.ty_is_opaque_future(ty) - // FIXME: This also includes non-async fns that return `impl Future`. && let async_fn_def_id = cx.tcx.parent(*future_def_id) + && matches!(cx.tcx.def_kind(async_fn_def_id), DefKind::Fn | DefKind::AssocFn) + // Check that this `impl Future` actually comes from an `async fn` + && cx.tcx.asyncness(async_fn_def_id).is_async() && check_must_use_def( cx, async_fn_def_id, @@ -123,7 +125,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults { let must_use_result = is_ty_must_use(cx, ty, &expr, expr.span); let type_lint_emitted_or_suppressed = match must_use_result { Some(path) => { - emit_must_use_untranslated(cx, &path, "", "", 1); + emit_must_use_untranslated(cx, &path, "", "", 1, false); true } None => false, @@ -254,24 +256,23 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults { } ty::Adt(def, _) => is_def_must_use(cx, def.did(), span), ty::Alias(ty::Opaque, ty::AliasTy { def_id: def, .. }) => { - elaborate_predicates_with_span( - cx.tcx, - cx.tcx.explicit_item_bounds(def).iter().cloned(), - ) - .find_map(|obligation| { - // We only look at the `DefId`, so it is safe to skip the binder here. - if let ty::PredicateKind::Clause(ty::Clause::Trait( - ref poly_trait_predicate, - )) = obligation.predicate.kind().skip_binder() - { - let def_id = poly_trait_predicate.trait_ref.def_id; - - is_def_must_use(cx, def_id, span) - } else { - None - } - }) - .map(|inner| MustUsePath::Opaque(Box::new(inner))) + elaborate(cx.tcx, cx.tcx.explicit_item_bounds(def).iter().cloned()) + // We only care about self bounds for the impl-trait + .filter_only_self() + .find_map(|(pred, _span)| { + // We only look at the `DefId`, so it is safe to skip the binder here. + if let ty::PredicateKind::Clause(ty::Clause::Trait( + ref poly_trait_predicate, + )) = pred.kind().skip_binder() + { + let def_id = poly_trait_predicate.trait_ref.def_id; + + is_def_must_use(cx, def_id, span) + } else { + None + } + }) + .map(|inner| MustUsePath::Opaque(Box::new(inner))) } ty::Dynamic(binders, _, _) => binders.iter().find_map(|predicate| { if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() @@ -358,6 +359,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults { descr_pre_path, descr_post_path, 1, + false, ) }) .is_some() @@ -370,6 +372,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults { descr_pre: &str, descr_post: &str, plural_len: usize, + is_inner: bool, ) { let plural_suffix = pluralize!(plural_len); @@ -377,20 +380,22 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults { MustUsePath::Suppressed => {} MustUsePath::Boxed(path) => { let descr_pre = &format!("{}boxed ", descr_pre); - emit_must_use_untranslated(cx, path, descr_pre, descr_post, plural_len); + emit_must_use_untranslated(cx, path, descr_pre, descr_post, plural_len, true); } MustUsePath::Opaque(path) => { let descr_pre = &format!("{}implementer{} of ", descr_pre, plural_suffix); - emit_must_use_untranslated(cx, path, descr_pre, descr_post, plural_len); + emit_must_use_untranslated(cx, path, descr_pre, descr_post, plural_len, true); } MustUsePath::TraitObject(path) => { let descr_post = &format!(" trait object{}{}", plural_suffix, descr_post); - emit_must_use_untranslated(cx, path, descr_pre, descr_post, plural_len); + emit_must_use_untranslated(cx, path, descr_pre, descr_post, plural_len, true); } MustUsePath::TupleElement(elems) => { for (index, path) in elems { let descr_post = &format!(" in tuple element {}", index); - emit_must_use_untranslated(cx, path, descr_pre, descr_post, plural_len); + emit_must_use_untranslated( + cx, path, descr_pre, descr_post, plural_len, true, + ); } } MustUsePath::Array(path, len) => { @@ -401,6 +406,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults { descr_pre, descr_post, plural_len.saturating_add(usize::try_from(*len).unwrap_or(usize::MAX)), + true, ); } MustUsePath::Closure(span) => { @@ -418,19 +424,6 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults { ); } MustUsePath::Def(span, def_id, reason) => { - let suggestion = if matches!( - cx.tcx.get_diagnostic_name(*def_id), - Some(sym::add) - | Some(sym::sub) - | Some(sym::mul) - | Some(sym::div) - | Some(sym::rem) - | Some(sym::neg), - ) { - Some(UnusedDefSuggestion::Default { span: span.shrink_to_lo() }) - } else { - None - }; cx.emit_spanned_lint( UNUSED_MUST_USE, *span, @@ -440,7 +433,8 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults { cx, def_id: *def_id, note: *reason, - suggestion, + suggestion: (!is_inner) + .then_some(UnusedDefSuggestion { span: span.shrink_to_lo() }), }, ); } @@ -812,7 +806,9 @@ trait UnusedDelimLint { fn check_item(&mut self, cx: &EarlyContext<'_>, item: &ast::Item) { use ast::ItemKind::*; - if let Const(.., Some(expr)) | Static(.., Some(expr)) = &item.kind { + if let Const(box ast::ConstItem { expr: Some(expr), .. }) + | Static(box ast::StaticItem { expr: Some(expr), .. }) = &item.kind + { self.check_unused_delims_expr( cx, expr, @@ -1349,9 +1345,8 @@ declare_lint! { /// ### Example /// /// ```rust - /// #![feature(box_syntax)] /// fn main() { - /// let a = (box [1, 2, 3]).len(); + /// let a = Box::new([1, 2, 3]).len(); /// } /// ``` /// @@ -1372,7 +1367,11 @@ declare_lint_pass!(UnusedAllocation => [UNUSED_ALLOCATION]); impl<'tcx> LateLintPass<'tcx> for UnusedAllocation { fn check_expr(&mut self, cx: &LateContext<'_>, e: &hir::Expr<'_>) { match e.kind { - hir::ExprKind::Box(_) => {} + hir::ExprKind::Call(path_expr, [_]) + if let hir::ExprKind::Path(qpath) = &path_expr.kind + && let Some(did) = cx.qpath_res(qpath, path_expr.hir_id).opt_def_id() + && cx.tcx.is_diagnostic_item(sym::box_new, did) + => {} _ => return, } |