diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index 3fb4e6c8fa5..0008f8f6d46 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -792,7 +792,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: store.register_late_pass(|_| Box::new(assertions_on_result_states::AssertionsOnResultStates)); store.register_late_pass(|_| Box::new(inherent_to_string::InherentToString)); let max_trait_bounds = conf.max_trait_bounds; - store.register_late_pass(move |_| Box::new(trait_bounds::TraitBounds::new(max_trait_bounds))); + store.register_late_pass(move |_| Box::new(trait_bounds::TraitBounds::new(max_trait_bounds, msrv()))); store.register_late_pass(|_| Box::new(comparison_chain::ComparisonChain)); let ignore_interior_mutability = conf.ignore_interior_mutability.clone(); store.register_late_pass(move |_| Box::new(mut_key::MutableKeyType::new(ignore_interior_mutability.clone()))); diff --git a/clippy_lints/src/trait_bounds.rs b/clippy_lints/src/trait_bounds.rs index 3917d8f0225..2cf3529bd1b 100644 --- a/clippy_lints/src/trait_bounds.rs +++ b/clippy_lints/src/trait_bounds.rs @@ -1,4 +1,5 @@ use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg}; +use clippy_utils::msrvs::{self, Msrv}; use clippy_utils::source::{snippet, snippet_opt, snippet_with_applicability}; use clippy_utils::{is_from_proc_macro, SpanlessEq, SpanlessHash}; use core::hash::{Hash, Hasher}; @@ -9,7 +10,7 @@ use rustc_data_structures::unhash::UnhashMap; use rustc_errors::Applicability; use rustc_hir::def::Res; use rustc_hir::{ - GenericArg, GenericBound, Generics, Item, ItemKind, Node, Path, PathSegment, PredicateOrigin, QPath, + GenericArg, GenericBound, Generics, Item, ItemKind, LangItem, Node, Path, PathSegment, PredicateOrigin, QPath, TraitBoundModifier, TraitItem, TraitRef, Ty, TyKind, WherePredicate, }; use rustc_lint::{LateContext, LateLintPass}; @@ -86,15 +87,16 @@ declare_clippy_lint! { "check if the same trait bounds are specified more than once during a generic declaration" } -#[derive(Copy, Clone)] +#[derive(Clone)] pub struct TraitBounds { max_trait_bounds: u64, + msrv: Msrv, } impl TraitBounds { #[must_use] - pub fn new(max_trait_bounds: u64) -> Self { - Self { max_trait_bounds } + pub fn new(max_trait_bounds: u64, msrv: Msrv) -> Self { + Self { max_trait_bounds, msrv } } } @@ -222,10 +224,24 @@ impl<'tcx> LateLintPass<'tcx> for TraitBounds { } } } + + extract_msrv_attr!(LateContext); } impl TraitBounds { - fn check_type_repetition<'tcx>(self, cx: &LateContext<'tcx>, gen: &'tcx Generics<'_>) { + /// Is the given bound a `?Sized` bound, and is combining it (i.e. `T: X + ?Sized`) an error on + /// this MSRV? See https://github.com/rust-lang/rust-clippy/issues/8772 for details. + fn cannot_combine_maybe_bound(&self, cx: &LateContext<'_>, bound: &GenericBound<'_>) -> bool { + if !self.msrv.meets(msrvs::COMBINED_MAYBE_BOUND) + && let GenericBound::Trait(tr, TraitBoundModifier::Maybe) = bound + { + cx.tcx.lang_items().get(LangItem::Sized) == tr.trait_ref.path.res.opt_def_id() + } else { + false + } + } + + fn check_type_repetition<'tcx>(&self, cx: &LateContext<'tcx>, gen: &'tcx Generics<'_>) { struct SpanlessTy<'cx, 'tcx> { ty: &'tcx Ty<'tcx>, cx: &'cx LateContext<'tcx>, @@ -256,10 +272,9 @@ impl TraitBounds { if p.origin != PredicateOrigin::ImplTrait; if p.bounds.len() as u64 <= self.max_trait_bounds; if !p.span.from_expansion(); - if let Some(ref v) = map.insert( - SpanlessTy { ty: p.bounded_ty, cx }, - p.bounds.iter().collect::>() - ); + let bounds = p.bounds.iter().filter(|b| !self.cannot_combine_maybe_bound(cx, b)).collect::>(); + if !bounds.is_empty(); + if let Some(ref v) = map.insert(SpanlessTy { ty: p.bounded_ty, cx }, bounds); if !is_from_proc_macro(cx, p.bounded_ty); then { let trait_bounds = v diff --git a/clippy_utils/src/msrvs.rs b/clippy_utils/src/msrvs.rs index e1b1a6f7184..b1f336461d1 100644 --- a/clippy_utils/src/msrvs.rs +++ b/clippy_utils/src/msrvs.rs @@ -47,6 +47,7 @@ msrv_aliases! { 1,18,0 { HASH_MAP_RETAIN, HASH_SET_RETAIN } 1,17,0 { FIELD_INIT_SHORTHAND, STATIC_IN_CONST, EXPECT_ERR } 1,16,0 { STR_REPEAT } + 1,15,0 { COMBINED_MAYBE_BOUND } } fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option) -> Option { diff --git a/tests/ui/type_repetition_in_bounds.rs b/tests/ui/type_repetition_in_bounds.rs index 1d36f4b3c7b..874d97f7a46 100644 --- a/tests/ui/type_repetition_in_bounds.rs +++ b/tests/ui/type_repetition_in_bounds.rs @@ -110,4 +110,28 @@ where // This should not lint fn impl_trait(_: impl AsRef, _: impl AsRef) {} +#[clippy::msrv = "1.14.0"] +mod issue8772_fail { + pub trait Trait {} + + pub fn f(arg: usize) + where + T: Trait, Box<[String]>, bool> + 'static, + U: Clone + Sync + 'static, + { + } +} + +#[clippy::msrv = "1.15.0"] +mod issue8772_pass { + pub trait Trait {} + + pub fn f(arg: usize) + where + T: Trait, Box<[String]>, bool> + 'static, + U: Clone + Sync + 'static, + { + } +} + fn main() {} diff --git a/tests/ui/type_repetition_in_bounds.stderr b/tests/ui/type_repetition_in_bounds.stderr index 56867f75b07..54973c5bda5 100644 --- a/tests/ui/type_repetition_in_bounds.stderr +++ b/tests/ui/type_repetition_in_bounds.stderr @@ -35,5 +35,13 @@ LL | T: ?Sized, | = help: consider combining the bounds: `T: Clone + ?Sized` -error: aborting due to 4 previous errors +error: this type has already been used as a bound predicate + --> $DIR/type_repetition_in_bounds.rs:131:9 + | +LL | T: Trait, Box<[String]>, bool> + 'static, + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = help: consider combining the bounds: `T: ?Sized + Trait, Box<[String]>, bool>` + +error: aborting due to 5 previous errors