From 2a73553513f393ab00e2da217ff0082403f1985b Mon Sep 17 00:00:00 2001 From: Bryanskiy Date: Fri, 23 Feb 2024 16:39:57 +0300 Subject: [PATCH 1/2] Support ?Trait bounds in supertraits and dyn Trait under a feature gate --- compiler/rustc_ast_lowering/src/item.rs | 10 +++- compiler/rustc_ast_lowering/src/lib.rs | 28 +++++----- .../rustc_ast_passes/src/ast_validation.rs | 28 +++++++--- compiler/rustc_feature/src/unstable.rs | 2 + compiler/rustc_hir/src/hir.rs | 6 ++- compiler/rustc_hir/src/intravisit.rs | 4 +- .../rustc_hir_analysis/src/check/wfcheck.rs | 2 +- .../src/collect/resolve_bound_vars.rs | 2 +- .../src/hir_ty_lowering/bounds.rs | 16 ++++-- .../src/hir_ty_lowering/errors.rs | 8 +-- .../src/hir_ty_lowering/lint.rs | 4 +- .../src/hir_ty_lowering/object_safety.rs | 9 ++-- compiler/rustc_hir_pretty/src/lib.rs | 5 +- compiler/rustc_lint/src/non_local_def.rs | 4 +- compiler/rustc_lint/src/traits.rs | 6 ++- compiler/rustc_span/src/symbol.rs | 1 + .../infer/nice_region_error/find_anon_type.rs | 2 +- .../nice_region_error/static_impl_trait.rs | 2 +- .../src/error_reporting/traits/mod.rs | 2 +- .../src/error_reporting/traits/suggestions.rs | 4 +- src/librustdoc/clean/mod.rs | 2 +- .../clippy/clippy_lints/src/lifetimes.rs | 2 +- .../clippy/clippy_lints/src/trait_bounds.rs | 6 +-- .../clippy_lints/src/types/borrowed_box.rs | 19 ++++--- .../clippy_lints/src/types/type_complexity.rs | 1 + .../feature-gate-more-maybe-bounds.rs | 17 ++++++ .../feature-gate-more-maybe-bounds.stderr | 53 +++++++++++++++++++ tests/ui/maybe-bounds.stderr | 15 ++++-- .../parser/trait-object-trait-parens.stderr | 18 +++++-- tests/ui/traits/maybe-polarity-pass.rs | 27 ++++++++++ tests/ui/traits/maybe-polarity-pass.stderr | 20 +++++++ tests/ui/traits/wf-object/maybe-bound.stderr | 26 +++++++-- .../traits/wf-object/only-maybe-bound.stderr | 8 ++- tests/ui/unsized/maybe-bounds-where.stderr | 31 ++++++++--- 34 files changed, 305 insertions(+), 85 deletions(-) create mode 100644 tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs create mode 100644 tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr create mode 100644 tests/ui/traits/maybe-polarity-pass.rs create mode 100644 tests/ui/traits/maybe-polarity-pass.stderr diff --git a/compiler/rustc_ast_lowering/src/item.rs b/compiler/rustc_ast_lowering/src/item.rs index f990b4ba69b..68745056438 100644 --- a/compiler/rustc_ast_lowering/src/item.rs +++ b/compiler/rustc_ast_lowering/src/item.rs @@ -1525,8 +1525,14 @@ fn lower_generics( continue; } let is_param = *is_param.get_or_insert_with(compute_is_param); - if !is_param { - self.dcx().emit_err(MisplacedRelaxTraitBound { span: bound.span() }); + if !is_param && !self.tcx.features().more_maybe_bounds { + self.tcx + .sess + .create_feature_err( + MisplacedRelaxTraitBound { span: bound.span() }, + sym::more_maybe_bounds, + ) + .emit(); } } } diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs index 0f5f4d8023b..218493cb7ea 100644 --- a/compiler/rustc_ast_lowering/src/lib.rs +++ b/compiler/rustc_ast_lowering/src/lib.rs @@ -1216,6 +1216,7 @@ fn lower_path_ty( itctx, TraitBoundModifiers::NONE, ); + let bound = (bound, hir::TraitBoundModifier::None); let bounds = this.arena.alloc_from_iter([bound]); let lifetime_bound = this.elided_dyn_bound(t.span); (bounds, lifetime_bound) @@ -1348,21 +1349,17 @@ fn lower_ty_direct(&mut self, t: &Ty, itctx: ImplTraitContext) -> hir::Ty<'hir> // We can safely ignore constness here since AST validation // takes care of rejecting invalid modifier combinations and // const trait bounds in trait object types. - GenericBound::Trait(ty, modifiers) => match modifiers.polarity { - BoundPolarity::Positive | BoundPolarity::Negative(_) => { - Some(this.lower_poly_trait_ref( - ty, - itctx, - // Still, don't pass along the constness here; we don't want to - // synthesize any host effect args, it'd only cause problems. - TraitBoundModifiers { - constness: BoundConstness::Never, - ..*modifiers - }, - )) - } - BoundPolarity::Maybe(_) => None, - }, + GenericBound::Trait(ty, modifiers) => { + // Still, don't pass along the constness here; we don't want to + // synthesize any host effect args, it'd only cause problems. + let modifiers = TraitBoundModifiers { + constness: BoundConstness::Never, + ..*modifiers + }; + let trait_ref = this.lower_poly_trait_ref(ty, itctx, modifiers); + let polarity = this.lower_trait_bound_modifiers(modifiers); + Some((trait_ref, polarity)) + } GenericBound::Outlives(lifetime) => { if lifetime_bound.is_none() { lifetime_bound = Some(this.lower_lifetime(lifetime)); @@ -2688,6 +2685,7 @@ fn ty_path(&mut self, mut hir_id: HirId, span: Span, qpath: hir::QPath<'hir>) -> trait_ref: hir::TraitRef { path, hir_ref_id: hir_id }, span: self.lower_span(span), }; + let principal = (principal, hir::TraitBoundModifier::None); // The original ID is taken by the `PolyTraitRef`, // so the `Ty` itself needs a different one. diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs index 1088db74cc9..9b063a330b7 100644 --- a/compiler/rustc_ast_passes/src/ast_validation.rs +++ b/compiler/rustc_ast_passes/src/ast_validation.rs @@ -1345,14 +1345,28 @@ fn visit_param_bound(&mut self, bound: &'a GenericBound, ctxt: BoundKind) { match bound { GenericBound::Trait(trait_ref, modifiers) => { match (ctxt, modifiers.constness, modifiers.polarity) { - (BoundKind::SuperTraits, BoundConstness::Never, BoundPolarity::Maybe(_)) => { - self.dcx().emit_err(errors::OptionalTraitSupertrait { - span: trait_ref.span, - path_str: pprust::path_to_string(&trait_ref.trait_ref.path), - }); + (BoundKind::SuperTraits, BoundConstness::Never, BoundPolarity::Maybe(_)) + if !self.features.more_maybe_bounds => + { + self.session + .create_feature_err( + errors::OptionalTraitSupertrait { + span: trait_ref.span, + path_str: pprust::path_to_string(&trait_ref.trait_ref.path), + }, + sym::more_maybe_bounds, + ) + .emit(); } - (BoundKind::TraitObject, BoundConstness::Never, BoundPolarity::Maybe(_)) => { - self.dcx().emit_err(errors::OptionalTraitObject { span: trait_ref.span }); + (BoundKind::TraitObject, BoundConstness::Never, BoundPolarity::Maybe(_)) + if !self.features.more_maybe_bounds => + { + self.session + .create_feature_err( + errors::OptionalTraitObject { span: trait_ref.span }, + sym::more_maybe_bounds, + ) + .emit(); } ( BoundKind::TraitObject, diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs index 9b5ed3b0876..d3d07181096 100644 --- a/compiler/rustc_feature/src/unstable.rs +++ b/compiler/rustc_feature/src/unstable.rs @@ -205,6 +205,8 @@ pub fn internal(&self, feature: Symbol) -> bool { (unstable, lifetime_capture_rules_2024, "1.76.0", None), /// Allows `#[link(..., cfg(..))]`; perma-unstable per #37406 (unstable, link_cfg, "1.14.0", None), + /// Allows using `?Trait` trait bounds in more contexts. + (internal, more_maybe_bounds, "CURRENT_RUSTC_VERSION", None), /// Allows the `multiple_supertrait_upcastable` lint. (unstable, multiple_supertrait_upcastable, "1.69.0", None), /// Allow negative trait bounds. This is an internal-only feature for testing the trait solver! diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs index 20b15499234..8c8f760bc41 100644 --- a/compiler/rustc_hir/src/hir.rs +++ b/compiler/rustc_hir/src/hir.rs @@ -2832,7 +2832,11 @@ pub enum TyKind<'hir> { OpaqueDef(ItemId, &'hir [GenericArg<'hir>], bool), /// A trait object type `Bound1 + Bound2 + Bound3` /// where `Bound` is a trait or a lifetime. - TraitObject(&'hir [PolyTraitRef<'hir>], &'hir Lifetime, TraitObjectSyntax), + TraitObject( + &'hir [(PolyTraitRef<'hir>, TraitBoundModifier)], + &'hir Lifetime, + TraitObjectSyntax, + ), /// Unused for now. Typeof(&'hir AnonConst), /// `TyKind::Infer` means the type should be inferred instead of it having been diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs index c202ee41e31..696f548f1ba 100644 --- a/compiler/rustc_hir/src/intravisit.rs +++ b/compiler/rustc_hir/src/intravisit.rs @@ -902,7 +902,9 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) -> V::Resul try_visit!(visitor.visit_array_length(length)); } TyKind::TraitObject(bounds, ref lifetime, _syntax) => { - walk_list!(visitor, visit_poly_trait_ref, bounds); + for (bound, _modifier) in bounds { + try_visit!(visitor.visit_poly_trait_ref(bound)); + } try_visit!(visitor.visit_lifetime(lifetime)); } TyKind::Typeof(ref expression) => try_visit!(visitor.visit_anon_const(expression)), diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs index 0316ef69bf8..456dc4e4e07 100644 --- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs +++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs @@ -831,7 +831,7 @@ fn visit_ty(&mut self, t: Ty<'tcx>) { fn could_be_self(trait_def_id: LocalDefId, ty: &hir::Ty<'_>) -> bool { match ty.kind { - hir::TyKind::TraitObject([trait_ref], ..) => match trait_ref.trait_ref.path.segments { + hir::TyKind::TraitObject([(trait_ref, _)], ..) => match trait_ref.trait_ref.path.segments { [s] => s.res.opt_def_id() == Some(trait_def_id.to_def_id()), _ => false, }, diff --git a/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs b/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs index 349dc9ad00e..02ea95852f0 100644 --- a/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs +++ b/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs @@ -652,7 +652,7 @@ fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) { debug!(?bounds, ?lifetime, "TraitObject"); let scope = Scope::TraitRefBoundary { s: self.scope }; self.with(scope, |this| { - for bound in bounds { + for (bound, _) in bounds { this.visit_poly_trait_ref_inner( bound, NonLifetimeBinderAllowed::Deny("trait object types"), diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs index 6f9c481650b..f05884f8912 100644 --- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs +++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs @@ -9,7 +9,7 @@ use rustc_middle::ty::print::PrintTraitRefExt as _; use rustc_middle::ty::{self as ty, IsSuggestable, Ty, TyCtxt}; use rustc_span::symbol::Ident; -use rustc_span::{ErrorGuaranteed, Span, Symbol}; +use rustc_span::{sym, ErrorGuaranteed, Span, Symbol}; use rustc_trait_selection::traits; use rustc_type_ir::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor}; use smallvec::SmallVec; @@ -75,10 +75,16 @@ pub(crate) fn add_sized_bound( } } - if unbounds.len() > 1 { - self.dcx().emit_err(errors::MultipleRelaxedDefaultBounds { - spans: unbounds.iter().map(|ptr| ptr.span).collect(), - }); + if unbounds.len() > 1 && !tcx.features().more_maybe_bounds { + self.tcx() + .sess + .create_feature_err( + errors::MultipleRelaxedDefaultBounds { + spans: unbounds.iter().map(|ptr| ptr.span).collect(), + }, + sym::more_maybe_bounds, + ) + .emit(); } let mut seen_sized_unbound = false; diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs index 8ff6ced8b39..e9ec2466089 100644 --- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs +++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs @@ -698,7 +698,7 @@ pub(crate) fn complain_about_missing_assoc_tys( &self, associated_types: FxIndexMap>, potential_assoc_types: Vec, - trait_bounds: &[hir::PolyTraitRef<'_>], + trait_bounds: &[(hir::PolyTraitRef<'_>, hir::TraitBoundModifier)], ) { if associated_types.values().all(|v| v.is_empty()) { return; @@ -744,12 +744,12 @@ pub(crate) fn complain_about_missing_assoc_tys( // related to issue #91997, turbofishes added only when in an expr or pat let mut in_expr_or_pat = false; if let ([], [bound]) = (&potential_assoc_types[..], &trait_bounds) { - let grandparent = tcx.parent_hir_node(tcx.parent_hir_id(bound.trait_ref.hir_ref_id)); + let grandparent = tcx.parent_hir_node(tcx.parent_hir_id(bound.0.trait_ref.hir_ref_id)); in_expr_or_pat = match grandparent { Node::Expr(_) | Node::Pat(_) => true, _ => false, }; - match bound.trait_ref.path.segments { + match bound.0.trait_ref.path.segments { // FIXME: `trait_ref.path.span` can point to a full path with multiple // segments, even though `trait_ref.path.segments` is of length `1`. Work // around that bug here, even though it should be fixed elsewhere. @@ -790,7 +790,7 @@ pub(crate) fn complain_about_missing_assoc_tys( // and we can then use their span to indicate this to the user. let bound_names = trait_bounds .iter() - .filter_map(|poly_trait_ref| { + .filter_map(|(poly_trait_ref, _)| { let path = poly_trait_ref.trait_ref.path.segments.last()?; let args = path.args?; diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs index 29c71c3fa50..e7aad0a29c5 100644 --- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs +++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs @@ -34,7 +34,7 @@ pub(super) fn prohibit_or_lint_bare_trait_object_ty( .ok() .is_some_and(|s| s.trim_end().ends_with('<')); - let is_global = poly_trait_ref.trait_ref.path.is_global(); + let is_global = poly_trait_ref.0.trait_ref.path.is_global(); let mut sugg = vec![( self_ty.span.shrink_to_lo(), @@ -176,7 +176,7 @@ fn maybe_suggest_impl_trait(&self, self_ty: &hir::Ty<'_>, diag: &mut Diag<'_>) - let mut is_downgradable = true; let is_object_safe = match self_ty.kind { hir::TyKind::TraitObject(objects, ..) => { - objects.iter().all(|o| match o.trait_ref.path.res { + objects.iter().all(|(o, _)| match o.trait_ref.path.res { Res::Def(DefKind::Trait, id) => { if Some(id) == owner { // For recursive traits, don't downgrade the error. (#119652) diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/object_safety.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/object_safety.rs index aafadc7f9cb..b3c7a1ff8a8 100644 --- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/object_safety.rs +++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/object_safety.rs @@ -27,7 +27,7 @@ pub(super) fn lower_trait_object_ty( &self, span: Span, hir_id: hir::HirId, - hir_trait_bounds: &[hir::PolyTraitRef<'tcx>], + hir_trait_bounds: &[(hir::PolyTraitRef<'tcx>, hir::TraitBoundModifier)], lifetime: &hir::Lifetime, borrowed: bool, representation: DynKind, @@ -37,7 +37,10 @@ pub(super) fn lower_trait_object_ty( let mut bounds = Bounds::default(); let mut potential_assoc_types = Vec::new(); let dummy_self = self.tcx().types.trait_object_dummy_self; - for trait_bound in hir_trait_bounds.iter().rev() { + for (trait_bound, modifier) in hir_trait_bounds.iter().rev() { + if *modifier == hir::TraitBoundModifier::Maybe { + continue; + } if let GenericArgCountResult { correct: Err(GenericArgCountMismatch { invalid_args: cur_potential_assoc_types, .. }), @@ -249,7 +252,7 @@ pub(super) fn lower_trait_object_ty( let args = tcx.mk_args(&args); let span = i.bottom().1; - let empty_generic_args = hir_trait_bounds.iter().any(|hir_bound| { + let empty_generic_args = hir_trait_bounds.iter().any(|(hir_bound, _)| { hir_bound.trait_ref.path.res == Res::Def(DefKind::Trait, trait_ref.def_id) && hir_bound.span.contains(span) }); diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs index db5eba0d9eb..0df9e063904 100644 --- a/compiler/rustc_hir_pretty/src/lib.rs +++ b/compiler/rustc_hir_pretty/src/lib.rs @@ -300,13 +300,16 @@ fn print_type(&mut self, ty: &hir::Ty<'_>) { self.word_space("dyn"); } let mut first = true; - for bound in bounds { + for (bound, modifier) in bounds { if first { first = false; } else { self.nbsp(); self.word_space("+"); } + if *modifier == TraitBoundModifier::Maybe { + self.word("?"); + } self.print_poly_trait_ref(bound); } if !lifetime.is_elided() { diff --git a/compiler/rustc_lint/src/non_local_def.rs b/compiler/rustc_lint/src/non_local_def.rs index 2f8eea6cd18..93c606a954e 100644 --- a/compiler/rustc_lint/src/non_local_def.rs +++ b/compiler/rustc_lint/src/non_local_def.rs @@ -429,7 +429,7 @@ fn ty_has_local_parent( path_has_local_parent(ty_path, cx, impl_parent, impl_parent_parent) } TyKind::TraitObject([principle_poly_trait_ref, ..], _, _) => path_has_local_parent( - principle_poly_trait_ref.trait_ref.path, + principle_poly_trait_ref.0.trait_ref.path, cx, impl_parent, impl_parent_parent, @@ -527,7 +527,7 @@ fn self_ty_kind_for_diagnostic(ty: &rustc_hir::Ty<'_>, tcx: TyCtxt<'_>) -> (Span .to_string(), ), TyKind::TraitObject([principle_poly_trait_ref, ..], _, _) => { - let path = &principle_poly_trait_ref.trait_ref.path; + let path = &principle_poly_trait_ref.0.trait_ref.path; ( path_span_without_args(path), path.res diff --git a/compiler/rustc_lint/src/traits.rs b/compiler/rustc_lint/src/traits.rs index 6983e7abbd6..552245f0cdd 100644 --- a/compiler/rustc_lint/src/traits.rs +++ b/compiler/rustc_lint/src/traits.rs @@ -113,9 +113,11 @@ fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'tcx>) { fn check_ty(&mut self, cx: &LateContext<'_>, ty: &'tcx hir::Ty<'tcx>) { let hir::TyKind::TraitObject(bounds, _lifetime, _syntax) = &ty.kind else { return }; - for bound in &bounds[..] { + for (bound, modifier) in &bounds[..] { let def_id = bound.trait_ref.trait_def_id(); - if cx.tcx.lang_items().drop_trait() == def_id { + if cx.tcx.lang_items().drop_trait() == def_id + && *modifier != hir::TraitBoundModifier::Maybe + { let Some(def_id) = cx.tcx.get_diagnostic_item(sym::needs_drop) else { return }; cx.emit_span_lint(DYN_DROP, bound.span, DropGlue { tcx: cx.tcx, def_id }); } diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index 2b30ca8a894..b40a7d17eef 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -1229,6 +1229,7 @@ modifiers, module, module_path, + more_maybe_bounds, more_qualified_paths, more_struct_aliases, movbe_target_feature, diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/find_anon_type.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/find_anon_type.rs index b91b755d683..a892ce58861 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/find_anon_type.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/find_anon_type.rs @@ -84,7 +84,7 @@ fn visit_ty(&mut self, arg: &'tcx hir::Ty<'tcx>) -> Self::Result { } hir::TyKind::TraitObject(bounds, ..) => { - for bound in bounds { + for (bound, _) in bounds { self.current_index.shift_in(1); self.visit_poly_trait_ref(bound); self.current_index.shift_out(1); diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs index ce157ff3dc8..e5d97976534 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs @@ -607,7 +607,7 @@ fn visit_ty(&mut self, t: &'tcx hir::Ty<'tcx>) { _, ) = t.kind { - for ptr in poly_trait_refs { + for (ptr, _) in poly_trait_refs { if Some(self.1) == ptr.trait_ref.trait_def_id() { self.0.push(ptr.span); } diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs index 87fdc5ddff8..89ae6f4ccab 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs @@ -437,7 +437,7 @@ pub fn report_object_safety_error<'tcx>( if tcx.parent_hir_node(hir_id).fn_sig().is_some() { // Do not suggest `impl Trait` when dealing with things like super-traits. err.span_suggestion_verbose( - ty.span.until(trait_ref.span), + ty.span.until(trait_ref.0.span), "consider using an opaque type instead", "impl ", Applicability::MaybeIncorrect, diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs index 885216e6216..d1381d24764 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs @@ -3040,11 +3040,11 @@ pub(super) fn note_obligation_cause_code( match ty.kind { hir::TyKind::TraitObject(traits, _, _) => { let (span, kw) = match traits { - [first, ..] if first.span.lo() == ty.span.lo() => { + [(first, _), ..] if first.span.lo() == ty.span.lo() => { // Missing `dyn` in front of trait object. (ty.span.shrink_to_lo(), "dyn ") } - [first, ..] => (ty.span.until(first.span), ""), + [(first, _), ..] => (ty.span.until(first.span), ""), [] => span_bug!(ty.span, "trait object with no traits: {ty:?}"), }; let needs_parens = traits.len() != 1; diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs index 2cd9b6fcd38..26011926cdd 100644 --- a/src/librustdoc/clean/mod.rs +++ b/src/librustdoc/clean/mod.rs @@ -1858,7 +1858,7 @@ pub(crate) fn clean_ty<'tcx>(ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> T } TyKind::Path(_) => clean_qpath(ty, cx), TyKind::TraitObject(bounds, ref lifetime, _) => { - let bounds = bounds.iter().map(|bound| clean_poly_trait_ref(bound, cx)).collect(); + let bounds = bounds.iter().map(|(bound, _)| clean_poly_trait_ref(bound, cx)).collect(); let lifetime = if !lifetime.is_elided() { Some(clean_lifetime(*lifetime, cx)) } else { None }; DynTrait(bounds, lifetime) diff --git a/src/tools/clippy/clippy_lints/src/lifetimes.rs b/src/tools/clippy/clippy_lints/src/lifetimes.rs index 443d6189c1f..f83101cee11 100644 --- a/src/tools/clippy/clippy_lints/src/lifetimes.rs +++ b/src/tools/clippy/clippy_lints/src/lifetimes.rs @@ -545,7 +545,7 @@ fn visit_ty(&mut self, ty: &'tcx Ty<'_>) { if !lt.is_elided() { self.unelided_trait_object_lifetime = true; } - for bound in bounds { + for (bound, _) in bounds { self.visit_poly_trait_ref(bound); } }, diff --git a/src/tools/clippy/clippy_lints/src/trait_bounds.rs b/src/tools/clippy/clippy_lints/src/trait_bounds.rs index 07390d6f430..41ebf59ae3a 100644 --- a/src/tools/clippy/clippy_lints/src/trait_bounds.rs +++ b/src/tools/clippy/clippy_lints/src/trait_bounds.rs @@ -181,7 +181,7 @@ fn check_ty(&mut self, cx: &LateContext<'tcx>, ty: &'tcx Ty<'tcx>) { // Iterate the bounds and add them to our seen hash // If we haven't yet seen it, add it to the fixed traits - for bound in bounds { + for (bound, _) in bounds { let Some(def_id) = bound.trait_ref.trait_def_id() else { continue; }; @@ -196,9 +196,9 @@ fn check_ty(&mut self, cx: &LateContext<'tcx>, ty: &'tcx Ty<'tcx>) { // If the number of unique traits isn't the same as the number of traits in the bounds, // there must be 1 or more duplicates if bounds.len() != unique_traits.len() { - let mut bounds_span = bounds[0].span; + let mut bounds_span = bounds[0].0.span; - for bound in bounds.iter().skip(1) { + for (bound, _) in bounds.iter().skip(1) { bounds_span = bounds_span.to(bound.span); } diff --git a/src/tools/clippy/clippy_lints/src/types/borrowed_box.rs b/src/tools/clippy/clippy_lints/src/types/borrowed_box.rs index 801e8862619..83cc9f2d8df 100644 --- a/src/tools/clippy/clippy_lints/src/types/borrowed_box.rs +++ b/src/tools/clippy/clippy_lints/src/types/borrowed_box.rs @@ -81,14 +81,17 @@ pub(super) fn check(cx: &LateContext<'_>, hir_ty: &hir::Ty<'_>, lt: &Lifetime, m // Returns true if given type is `Any` trait. fn is_any_trait(cx: &LateContext<'_>, t: &hir::Ty<'_>) -> bool { - if let TyKind::TraitObject(traits, ..) = t.kind - && !traits.is_empty() - && let Some(trait_did) = traits[0].trait_ref.trait_def_id() - // Only Send/Sync can be used as additional traits, so it is enough to - // check only the first trait. - && cx.tcx.is_diagnostic_item(sym::Any, trait_did) - { - return true; + if let TyKind::TraitObject(traits, ..) = t.kind { + return traits + .iter() + .any(|(bound, _)| { + if let Some(trait_did) = bound.trait_ref.trait_def_id() + && cx.tcx.is_diagnostic_item(sym::Any, trait_did) + { + return true; + } + false + }); } false diff --git a/src/tools/clippy/clippy_lints/src/types/type_complexity.rs b/src/tools/clippy/clippy_lints/src/types/type_complexity.rs index b6e765d7c39..7fcfd5c8f35 100644 --- a/src/tools/clippy/clippy_lints/src/types/type_complexity.rs +++ b/src/tools/clippy/clippy_lints/src/types/type_complexity.rs @@ -55,6 +55,7 @@ fn visit_ty(&mut self, ty: &'tcx hir::Ty<'_>) { TyKind::TraitObject(param_bounds, _, _) => { let has_lifetime_parameters = param_bounds.iter().any(|bound| { bound + .0 .bound_generic_params .iter() .any(|param| matches!(param.kind, GenericParamKind::Lifetime { .. })) diff --git a/tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs new file mode 100644 index 00000000000..4541499b7c7 --- /dev/null +++ b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs @@ -0,0 +1,17 @@ +#![feature(auto_traits)] + +trait Trait1 {} +auto trait Trait2 {} +trait Trait3: ?Trait1 {} +//~^ ERROR `?Trait` is not permitted in supertraits +trait Trait4 where Self: ?Trait1 {} +//~^ ERROR ?Trait` bounds are only permitted at the point where a type parameter is declared + +fn foo(_: Box) {} +//~^ ERROR `?Trait` is not permitted in trait object types +fn bar(_: T) {} +//~^ ERROR type parameter has more than one relaxed default bound, only one is supported +//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default +//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + +fn main() {} diff --git a/tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr new file mode 100644 index 00000000000..2b7a353020a --- /dev/null +++ b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr @@ -0,0 +1,53 @@ +error[E0658]: `?Trait` is not permitted in supertraits + --> $DIR/feature-gate-more-maybe-bounds.rs:5:15 + | +LL | trait Trait3: ?Trait1 {} + | ^^^^^^^ + | + = note: traits are `?Trait1` by default + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +error[E0658]: `?Trait` is not permitted in trait object types + --> $DIR/feature-gate-more-maybe-bounds.rs:10:28 + | +LL | fn foo(_: Box) {} + | ^^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared + --> $DIR/feature-gate-more-maybe-bounds.rs:7:26 + | +LL | trait Trait4 where Self: ?Trait1 {} + | ^^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +error[E0203]: type parameter has more than one relaxed default bound, only one is supported + --> $DIR/feature-gate-more-maybe-bounds.rs:12:11 + | +LL | fn bar(_: T) {} + | ^^^^^^^ ^^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/feature-gate-more-maybe-bounds.rs:12:11 + | +LL | fn bar(_: T) {} + | ^^^^^^^ + +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/feature-gate-more-maybe-bounds.rs:12:21 + | +LL | fn bar(_: T) {} + | ^^^^^^^ + +error: aborting due to 4 previous errors; 2 warnings emitted + +Some errors have detailed explanations: E0203, E0658. +For more information about an error, try `rustc --explain E0203`. diff --git a/tests/ui/maybe-bounds.stderr b/tests/ui/maybe-bounds.stderr index 1d823b6acb2..230d11fd0ae 100644 --- a/tests/ui/maybe-bounds.stderr +++ b/tests/ui/maybe-bounds.stderr @@ -1,22 +1,31 @@ -error: `?Trait` is not permitted in supertraits +error[E0658]: `?Trait` is not permitted in supertraits --> $DIR/maybe-bounds.rs:1:11 | LL | trait Tr: ?Sized {} | ^^^^^^ | = note: traits are `?Sized` by default + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/maybe-bounds.rs:4:20 | LL | type A1 = dyn Tr + (?Sized); | ^^^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/maybe-bounds.rs:6:28 | LL | type A2 = dyn for<'a> Tr + (?Sized); | ^^^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error: aborting due to 3 previous errors +For more information about this error, try `rustc --explain E0658`. diff --git a/tests/ui/parser/trait-object-trait-parens.stderr b/tests/ui/parser/trait-object-trait-parens.stderr index 3134746b930..ff32b173d49 100644 --- a/tests/ui/parser/trait-object-trait-parens.stderr +++ b/tests/ui/parser/trait-object-trait-parens.stderr @@ -1,20 +1,29 @@ -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/trait-object-trait-parens.rs:8:24 | LL | let _: Box<(Obj) + (?Sized) + (for<'a> Trait<'a>)>; | ^^^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/trait-object-trait-parens.rs:13:16 | LL | let _: Box Trait<'a>) + (Obj)>; | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/trait-object-trait-parens.rs:18:44 | LL | let _: Box Trait<'a> + (Obj) + (?Sized)>; | ^^^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date warning: trait objects without an explicit `dyn` are deprecated --> $DIR/trait-object-trait-parens.rs:8:16 @@ -91,4 +100,5 @@ LL | let _: Box Trait<'a> + (Obj) + (?Sized)>; error: aborting due to 6 previous errors; 3 warnings emitted -For more information about this error, try `rustc --explain E0225`. +Some errors have detailed explanations: E0225, E0658. +For more information about an error, try `rustc --explain E0225`. diff --git a/tests/ui/traits/maybe-polarity-pass.rs b/tests/ui/traits/maybe-polarity-pass.rs new file mode 100644 index 00000000000..075a0d8dcac --- /dev/null +++ b/tests/ui/traits/maybe-polarity-pass.rs @@ -0,0 +1,27 @@ +//@ check-pass + +#![feature(auto_traits)] +#![feature(more_maybe_bounds)] +#![feature(negative_impls)] + +trait Trait1 {} +auto trait Trait2 {} + +trait Trait3 : ?Trait1 {} +trait Trait4 where Self: Trait1 {} + +fn foo(_: Box<(dyn Trait3 + ?Trait2)>) {} +fn bar(_: &T) {} +//~^ WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default +//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default +//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + +struct S; +impl !Trait2 for S {} +impl Trait1 for S {} +impl Trait3 for S {} + +fn main() { + foo(Box::new(S)); + bar(&S); +} diff --git a/tests/ui/traits/maybe-polarity-pass.stderr b/tests/ui/traits/maybe-polarity-pass.stderr new file mode 100644 index 00000000000..09ed52f5b0d --- /dev/null +++ b/tests/ui/traits/maybe-polarity-pass.stderr @@ -0,0 +1,20 @@ +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/maybe-polarity-pass.rs:14:20 + | +LL | fn bar(_: &T) {} + | ^^^^^^^ + +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/maybe-polarity-pass.rs:14:30 + | +LL | fn bar(_: &T) {} + | ^^^^^^^ + +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/maybe-polarity-pass.rs:14:40 + | +LL | fn bar(_: &T) {} + | ^^^^^^^ + +warning: 3 warnings emitted + diff --git a/tests/ui/traits/wf-object/maybe-bound.stderr b/tests/ui/traits/wf-object/maybe-bound.stderr index 2fe3f0fc39f..be7afabd0d0 100644 --- a/tests/ui/traits/wf-object/maybe-bound.stderr +++ b/tests/ui/traits/wf-object/maybe-bound.stderr @@ -1,32 +1,48 @@ -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/maybe-bound.rs:5:15 | LL | type _0 = dyn ?Sized + Foo; | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/maybe-bound.rs:8:21 | LL | type _1 = dyn Foo + ?Sized; | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/maybe-bound.rs:11:21 | LL | type _2 = dyn Foo + ?Sized + ?Sized; | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/maybe-bound.rs:11:30 | LL | type _2 = dyn Foo + ?Sized + ?Sized; | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/maybe-bound.rs:15:15 | LL | type _3 = dyn ?Sized + Foo; | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error: aborting due to 5 previous errors +For more information about this error, try `rustc --explain E0658`. diff --git a/tests/ui/traits/wf-object/only-maybe-bound.stderr b/tests/ui/traits/wf-object/only-maybe-bound.stderr index cbc41feec1e..26269476eaa 100644 --- a/tests/ui/traits/wf-object/only-maybe-bound.stderr +++ b/tests/ui/traits/wf-object/only-maybe-bound.stderr @@ -1,8 +1,11 @@ -error: `?Trait` is not permitted in trait object types +error[E0658]: `?Trait` is not permitted in trait object types --> $DIR/only-maybe-bound.rs:3:15 | LL | type _0 = dyn ?Sized; | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error[E0224]: at least one trait is required for an object type --> $DIR/only-maybe-bound.rs:3:11 @@ -12,4 +15,5 @@ LL | type _0 = dyn ?Sized; error: aborting due to 2 previous errors -For more information about this error, try `rustc --explain E0224`. +Some errors have detailed explanations: E0224, E0658. +For more information about an error, try `rustc --explain E0224`. diff --git a/tests/ui/unsized/maybe-bounds-where.stderr b/tests/ui/unsized/maybe-bounds-where.stderr index 683bd387bb2..f7851261667 100644 --- a/tests/ui/unsized/maybe-bounds-where.stderr +++ b/tests/ui/unsized/maybe-bounds-where.stderr @@ -1,32 +1,47 @@ -error: `?Trait` bounds are only permitted at the point where a type parameter is declared +error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared --> $DIR/maybe-bounds-where.rs:1:28 | LL | struct S1(T) where (T): ?Sized; | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` bounds are only permitted at the point where a type parameter is declared +error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared --> $DIR/maybe-bounds-where.rs:4:27 | LL | struct S2(T) where u8: ?Sized; | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` bounds are only permitted at the point where a type parameter is declared +error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared --> $DIR/maybe-bounds-where.rs:7:35 | LL | struct S3(T) where &'static T: ?Sized; | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` bounds are only permitted at the point where a type parameter is declared +error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared --> $DIR/maybe-bounds-where.rs:12:34 | LL | struct S4(T) where for<'a> T: ?Trait<'a>; | ^^^^^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: `?Trait` bounds are only permitted at the point where a type parameter is declared +error[E0658]: `?Trait` bounds are only permitted at the point where a type parameter is declared --> $DIR/maybe-bounds-where.rs:21:21 | LL | fn f() where T: ?Sized {} | ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default --> $DIR/maybe-bounds-where.rs:12:34 @@ -39,6 +54,9 @@ error[E0203]: type parameter has more than one relaxed default bound, only one i | LL | struct S5(*const T) where T: ?Trait<'static> + ?Sized; | ^^^^^^^^^^^^^^^ ^^^^^^ + | + = help: add `#![feature(more_maybe_bounds)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default --> $DIR/maybe-bounds-where.rs:16:33 @@ -48,4 +66,5 @@ LL | struct S5(*const T) where T: ?Trait<'static> + ?Sized; error: aborting due to 6 previous errors; 2 warnings emitted -For more information about this error, try `rustc --explain E0203`. +Some errors have detailed explanations: E0203, E0658. +For more information about an error, try `rustc --explain E0203`. From fd9d0bfbacc2d5af183ba394ca16cb2581dab02d Mon Sep 17 00:00:00 2001 From: Bryanskiy Date: Fri, 26 Jul 2024 16:33:30 +0300 Subject: [PATCH 2/2] Forbid `?Trait` bounds repetitions --- .../src/hir_ty_lowering/bounds.rs | 26 ++++++++++++------- .../feature-gate-more-maybe-bounds.rs | 7 +++++ .../feature-gate-more-maybe-bounds.stderr | 20 +++++++++++++- tests/ui/traits/maybe-polarity-repeated.rs | 9 +++++++ .../ui/traits/maybe-polarity-repeated.stderr | 21 +++++++++++++++ 5 files changed, 72 insertions(+), 11 deletions(-) create mode 100644 tests/ui/traits/maybe-polarity-repeated.rs create mode 100644 tests/ui/traits/maybe-polarity-repeated.stderr diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs index f05884f8912..9d839908559 100644 --- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs +++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs @@ -75,16 +75,22 @@ pub(crate) fn add_sized_bound( } } - if unbounds.len() > 1 && !tcx.features().more_maybe_bounds { - self.tcx() - .sess - .create_feature_err( - errors::MultipleRelaxedDefaultBounds { - spans: unbounds.iter().map(|ptr| ptr.span).collect(), - }, - sym::more_maybe_bounds, - ) - .emit(); + let mut unique_bounds = FxIndexSet::default(); + let mut seen_repeat = false; + for unbound in &unbounds { + if let Res::Def(DefKind::Trait, unbound_def_id) = unbound.trait_ref.path.res { + seen_repeat |= !unique_bounds.insert(unbound_def_id); + } + } + if unbounds.len() > 1 { + let err = errors::MultipleRelaxedDefaultBounds { + spans: unbounds.iter().map(|ptr| ptr.span).collect(), + }; + if seen_repeat { + self.dcx().emit_err(err); + } else if !tcx.features().more_maybe_bounds { + self.tcx().sess.create_feature_err(err, sym::more_maybe_bounds).emit(); + }; } let mut seen_sized_unbound = false; diff --git a/tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs index 4541499b7c7..debe143b091 100644 --- a/tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs +++ b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.rs @@ -14,4 +14,11 @@ fn bar(_: T) {} //~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default //~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default +trait Trait {} +// Do not suggest `#![feature(more_maybe_bounds)]` for repetitions +fn baz(_ : T) {} +//~^ ERROR type parameter has more than one relaxed default bound, only one is supported +//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default +//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + fn main() {} diff --git a/tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr index 2b7a353020a..e6d65e05997 100644 --- a/tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr +++ b/tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr @@ -47,7 +47,25 @@ warning: relaxing a default bound only does something for `?Sized`; all other tr LL | fn bar(_: T) {} | ^^^^^^^ -error: aborting due to 4 previous errors; 2 warnings emitted +error[E0203]: type parameter has more than one relaxed default bound, only one is supported + --> $DIR/feature-gate-more-maybe-bounds.rs:19:11 + | +LL | fn baz(_ : T) {} + | ^^^^^^ ^^^^^^ + +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/feature-gate-more-maybe-bounds.rs:19:11 + | +LL | fn baz(_ : T) {} + | ^^^^^^ + +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/feature-gate-more-maybe-bounds.rs:19:20 + | +LL | fn baz(_ : T) {} + | ^^^^^^ + +error: aborting due to 5 previous errors; 4 warnings emitted Some errors have detailed explanations: E0203, E0658. For more information about an error, try `rustc --explain E0203`. diff --git a/tests/ui/traits/maybe-polarity-repeated.rs b/tests/ui/traits/maybe-polarity-repeated.rs new file mode 100644 index 00000000000..4b5ec83fffa --- /dev/null +++ b/tests/ui/traits/maybe-polarity-repeated.rs @@ -0,0 +1,9 @@ +#![feature(more_maybe_bounds)] + +trait Trait {} +fn foo(_: T) {} +//~^ ERROR type parameter has more than one relaxed default bound, only one is supported +//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default +//~| WARN relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + +fn main() {} diff --git a/tests/ui/traits/maybe-polarity-repeated.stderr b/tests/ui/traits/maybe-polarity-repeated.stderr new file mode 100644 index 00000000000..610c484fbec --- /dev/null +++ b/tests/ui/traits/maybe-polarity-repeated.stderr @@ -0,0 +1,21 @@ +error[E0203]: type parameter has more than one relaxed default bound, only one is supported + --> $DIR/maybe-polarity-repeated.rs:4:11 + | +LL | fn foo(_: T) {} + | ^^^^^^ ^^^^^^ + +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/maybe-polarity-repeated.rs:4:11 + | +LL | fn foo(_: T) {} + | ^^^^^^ + +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/maybe-polarity-repeated.rs:4:20 + | +LL | fn foo(_: T) {} + | ^^^^^^ + +error: aborting due to 1 previous error; 2 warnings emitted + +For more information about this error, try `rustc --explain E0203`.