diff options
| -rw-r--r-- | clippy_lints/src/unit_return_expecting_ord.rs | 126 |
1 files changed, 79 insertions, 47 deletions
diff --git a/clippy_lints/src/unit_return_expecting_ord.rs b/clippy_lints/src/unit_return_expecting_ord.rs index 67ceac92dbc..39f4130afcf 100644 --- a/clippy_lints/src/unit_return_expecting_ord.rs +++ b/clippy_lints/src/unit_return_expecting_ord.rs @@ -5,7 +5,7 @@ use rustc_lint::{LateContext, LateLintPass}; use rustc_middle::ty; use rustc_middle::ty::{ClauseKind, GenericPredicates, ProjectionPredicate, TraitPredicate}; use rustc_session::declare_lint_pass; -use rustc_span::{BytePos, Span, sym}; +use rustc_span::{BytePos, Span, Symbol, sym}; declare_clippy_lint! { /// ### What it does @@ -36,21 +36,26 @@ declare_clippy_lint! { declare_lint_pass!(UnitReturnExpectingOrd => [UNIT_RETURN_EXPECTING_ORD]); -fn get_trait_predicates_for_trait_id<'tcx>( +// For each +fn get_trait_predicates_for_trait_ids<'tcx>( cx: &LateContext<'tcx>, generics: GenericPredicates<'tcx>, - trait_id: Option<DefId>, -) -> Vec<TraitPredicate<'tcx>> { - let mut preds = Vec::new(); + trait_ids: &[Option<DefId>], // At least 2 ids +) -> [Vec<TraitPredicate<'tcx>>; 3] { + debug_assert!(trait_ids.len() >= 2); + let mut preds = [Vec::new(), Vec::new(), Vec::new()]; for (pred, _) in generics.predicates { - if let ClauseKind::Trait(poly_trait_pred) = pred.kind().skip_binder() - && let trait_pred = cx + if let ClauseKind::Trait(poly_trait_pred) = pred.kind().skip_binder() { + let trait_pred = cx .tcx - .instantiate_bound_regions_with_erased(pred.kind().rebind(poly_trait_pred)) - && let Some(trait_def_id) = trait_id - && trait_def_id == trait_pred.trait_ref.def_id - { - preds.push(trait_pred); + .instantiate_bound_regions_with_erased(pred.kind().rebind(poly_trait_pred)); + for (i, tid) in trait_ids.iter().enumerate() { + if let Some(tid) = tid + && *tid == trait_pred.trait_ref.def_id + { + preds[i].push(trait_pred); + } + } } } preds @@ -74,15 +79,24 @@ fn get_projection_pred<'tcx>( }) } -fn get_args_to_check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> Vec<(usize, String)> { +fn get_args_to_check<'tcx>( + cx: &LateContext<'tcx>, + expr: &'tcx Expr<'tcx>, + args_len: usize, + fn_mut_trait: DefId, + ord_trait: Option<DefId>, + partial_ord_trait: Option<DefId>, +) -> Vec<(usize, Symbol)> { let mut args_to_check = Vec::new(); if let Some(def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) { let fn_sig = cx.tcx.fn_sig(def_id).instantiate_identity(); let generics = cx.tcx.predicates_of(def_id); - let fn_mut_preds = get_trait_predicates_for_trait_id(cx, generics, cx.tcx.lang_items().fn_mut_trait()); - let ord_preds = get_trait_predicates_for_trait_id(cx, generics, cx.tcx.get_diagnostic_item(sym::Ord)); - let partial_ord_preds = - get_trait_predicates_for_trait_id(cx, generics, cx.tcx.lang_items().partial_ord_trait()); + let [fn_mut_preds, ord_preds, partial_ord_preds] = + get_trait_predicates_for_trait_ids(cx, generics, &[Some(fn_mut_trait), ord_trait, partial_ord_trait]); + if fn_mut_preds.is_empty() { + return vec![]; + } + // Trying to call instantiate_bound_regions_with_erased on fn_sig.inputs() gives the following error // The trait `rustc::ty::TypeFoldable<'_>` is not implemented for // `&[rustc_middle::ty::Ty<'_>]` @@ -102,12 +116,18 @@ fn get_args_to_check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> Ve .iter() .any(|ord| Some(ord.self_ty()) == return_ty_pred.term.as_type()) { - args_to_check.push((i, "Ord".to_string())); + args_to_check.push((i, sym::Ord)); + if args_to_check.len() == args_len - 1 { + break; + } } else if partial_ord_preds .iter() .any(|pord| pord.self_ty() == return_ty_pred.term.expect_type()) { - args_to_check.push((i, "PartialOrd".to_string())); + args_to_check.push((i, sym::PartialOrd)); + if args_to_check.len() == args_len - 1 { + break; + } } } } @@ -142,38 +162,50 @@ fn check_arg<'tcx>(cx: &LateContext<'tcx>, arg: &'tcx Expr<'tcx>) -> Option<(Spa impl<'tcx> LateLintPass<'tcx> for UnitReturnExpectingOrd { fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) { - if let ExprKind::MethodCall(_, receiver, args, _) = expr.kind { - let arg_indices = get_args_to_check(cx, expr); + if let ExprKind::MethodCall(_, receiver, args, _) = expr.kind + && args.iter().any(|arg| { + matches!( + arg.peel_blocks().peel_borrows().peel_drop_temps().kind, + ExprKind::Path(_) | ExprKind::Closure(_) + ) + }) + && let Some(fn_mut_trait) = cx.tcx.lang_items().fn_mut_trait() + { + let ord_trait = cx.tcx.get_diagnostic_item(sym::Ord); + let partial_ord_trait = cx.tcx.lang_items().partial_ord_trait(); + if (ord_trait, partial_ord_trait) == (None, None) { + return; + } + let args = std::iter::once(receiver).chain(args.iter()).collect::<Vec<_>>(); + let arg_indices = get_args_to_check(cx, expr, args.len(), fn_mut_trait, ord_trait, partial_ord_trait); for (i, trait_name) in arg_indices { - if i < args.len() { - match check_arg(cx, args[i]) { - Some((span, None)) => { - span_lint( - cx, - UNIT_RETURN_EXPECTING_ORD, - span, - format!( - "this closure returns \ + match check_arg(cx, args[i]) { + Some((span, None)) => { + span_lint( + cx, + UNIT_RETURN_EXPECTING_ORD, + span, + format!( + "this closure returns \ the unit type which also implements {trait_name}" - ), - ); - }, - Some((span, Some(last_semi))) => { - span_lint_and_help( - cx, - UNIT_RETURN_EXPECTING_ORD, - span, - format!( - "this closure returns \ + ), + ); + }, + Some((span, Some(last_semi))) => { + span_lint_and_help( + cx, + UNIT_RETURN_EXPECTING_ORD, + span, + format!( + "this closure returns \ the unit type which also implements {trait_name}" - ), - Some(last_semi), - "probably caused by this trailing semicolon", - ); - }, - None => {}, - } + ), + Some(last_semi), + "probably caused by this trailing semicolon", + ); + }, + None => {}, } } } |