Represent TraitBoundModifiers as distinct parts in HIR

clippy_lints/src/implied_bounds_in_impls.rs

@@ -3,7 +3,7 @@ use clippy_utils::source::snippet;
 use rustc_errors::{Applicability, SuggestionStyle};
 use rustc_hir::def_id::DefId;
 use rustc_hir::{
-    AssocItemConstraint, GenericArg, GenericBound, GenericBounds, PredicateOrigin, TraitBoundModifier, TyKind,
+    AssocItemConstraint, GenericArg, GenericBound, GenericBounds, PredicateOrigin, TraitBoundModifiers, TyKind,
     WherePredicate,
 };
 use rustc_hir_analysis::lower_ty;
@@ -234,7 +234,7 @@ fn collect_supertrait_bounds<'tcx>(cx: &LateContext<'tcx>, bounds: GenericBounds
         .iter()
         .filter_map(|bound| {
             if let GenericBound::Trait(poly_trait) = bound
-                && let TraitBoundModifier::None = poly_trait.modifiers
+                && let TraitBoundModifiers::NONE = poly_trait.modifiers
                 && let [.., path] = poly_trait.trait_ref.path.segments
                 && poly_trait.bound_generic_params.is_empty()
                 && let Some(trait_def_id) = path.res.opt_def_id()
@@ -300,7 +300,7 @@ fn check<'tcx>(cx: &LateContext<'tcx>, bounds: GenericBounds<'tcx>) {
     // simply comparing trait `DefId`s won't be enough. We also need to compare the generics.
     for (index, bound) in bounds.iter().enumerate() {
         if let GenericBound::Trait(poly_trait) = bound
-            && let TraitBoundModifier::None = poly_trait.modifiers
+            && let TraitBoundModifiers::NONE = poly_trait.modifiers
             && let [.., path] = poly_trait.trait_ref.path.segments
             && let implied_args = path.args.map_or([].as_slice(), |a| a.args)
             && let implied_constraints = path.args.map_or([].as_slice(), |a| a.constraints)

clippy_lints/src/needless_maybe_sized.rs

@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use rustc_errors::Applicability;
 use rustc_hir::def_id::{DefId, DefIdMap};
-use rustc_hir::{GenericBound, Generics, PolyTraitRef, TraitBoundModifier, WherePredicate};
+use rustc_hir::{GenericBound, Generics, PolyTraitRef, TraitBoundModifiers, BoundPolarity, WherePredicate};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::{ClauseKind, PredicatePolarity};
 use rustc_session::declare_lint_pass;
@@ -118,13 +118,13 @@ impl LateLintPass<'_> for NeedlessMaybeSized {
         let maybe_sized_params: DefIdMap<_> = type_param_bounds(generics)
             .filter(|bound| {
                 bound.trait_bound.trait_ref.trait_def_id() == Some(sized_trait)
-                    && bound.trait_bound.modifiers == TraitBoundModifier::Maybe
+                    && matches!(bound.trait_bound.modifiers.polarity, BoundPolarity::Maybe(_))
             })
             .map(|bound| (bound.param, bound))
             .collect();
 
         for bound in type_param_bounds(generics) {
-            if bound.trait_bound.modifiers == TraitBoundModifier::None
+            if bound.trait_bound.modifiers == TraitBoundModifiers::NONE
                 && let Some(sized_bound) = maybe_sized_params.get(&bound.param)
                 && let Some(path) = path_to_sized_bound(cx, bound.trait_bound)
             {

clippy_lints/src/trait_bounds.rs

@@ -11,7 +11,7 @@ use rustc_errors::Applicability;
 use rustc_hir::def::Res;
 use rustc_hir::{
     GenericBound, Generics, Item, ItemKind, LangItem, Node, Path, PathSegment, PredicateOrigin, QPath,
-    TraitBoundModifier, TraitItem, TraitRef, Ty, TyKind, WherePredicate,
+    TraitBoundModifiers, TraitItem, TraitRef, Ty, TyKind, WherePredicate, BoundPolarity,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::impl_lint_pass;
@@ -233,7 +233,7 @@ impl TraitBounds {
     fn cannot_combine_maybe_bound(&self, cx: &LateContext<'_>, bound: &GenericBound<'_>) -> bool {
         if !self.msrv.meets(msrvs::MAYBE_BOUND_IN_WHERE)
             && let GenericBound::Trait(tr) = bound
-            && let TraitBoundModifier::Maybe = tr.modifiers
+            && let BoundPolarity::Maybe(_) = tr.modifiers.polarity
         {
             cx.tcx.lang_items().get(LangItem::Sized) == tr.trait_ref.path.res.opt_def_id()
         } else {
@@ -374,12 +374,12 @@ fn check_trait_bound_duplication<'tcx>(cx: &LateContext<'tcx>, generics: &'_ Gen
 struct ComparableTraitRef<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
     trait_ref: &'tcx TraitRef<'tcx>,
-    modifier: TraitBoundModifier,
+    modifiers: TraitBoundModifiers,
 }
 
 impl PartialEq for ComparableTraitRef<'_, '_> {
     fn eq(&self, other: &Self) -> bool {
-        self.modifier == other.modifier
+        SpanlessEq::new(self.cx).eq_modifiers(self.modifiers, other.modifiers)
             && SpanlessEq::new(self.cx)
                 .paths_by_resolution()
                 .eq_path(self.trait_ref.path, other.trait_ref.path)
@@ -390,8 +390,8 @@ impl Hash for ComparableTraitRef<'_, '_> {
     fn hash<H: Hasher>(&self, state: &mut H) {
         let mut s = SpanlessHash::new(self.cx).paths_by_resolution();
         s.hash_path(self.trait_ref.path);
+        s.hash_modifiers(self.modifiers);
         state.write_u64(s.finish());
-        self.modifier.hash(state);
     }
 }
 
@@ -400,7 +400,7 @@ fn get_trait_info_from_bound<'a>(bound: &'a GenericBound<'_>) -> Option<(Res, &'
         let trait_path = t.trait_ref.path;
         let trait_span = {
             let path_span = trait_path.span;
-            if let TraitBoundModifier::Maybe = t.modifiers {
+            if let BoundPolarity::Maybe(_) = t.modifiers.polarity {
                 path_span.with_lo(path_span.lo() - BytePos(1)) // include the `?`
             } else {
                 path_span
@@ -427,7 +427,7 @@ fn rollup_traits<'cx, 'tcx>(
                 ComparableTraitRef {
                     cx,
                     trait_ref: &t.trait_ref,
-                    modifier: t.modifiers,
+                    modifiers: t.modifiers,
                 },
                 t.span,
             ))

clippy_utils/src/hir_utils.rs

@@ -9,7 +9,8 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{
     ArrayLen, AssocItemConstraint, BinOpKind, BindingMode, Block, BodyId, Closure, ConstArg, ConstArgKind, Expr,
     ExprField, ExprKind, FnRetTy, GenericArg, GenericArgs, HirId, HirIdMap, InlineAsmOperand, LetExpr, Lifetime,
-    LifetimeName, Pat, PatField, PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind, Ty, TyKind,
+    LifetimeName, Pat, PatField, PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind, TraitBoundModifiers, Ty,
+    TyKind,
 };
 use rustc_lexer::{TokenKind, tokenize};
 use rustc_lint::LateContext;
@@ -126,6 +127,11 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
     pub fn eq_path_segments(&mut self, left: &[PathSegment<'_>], right: &[PathSegment<'_>]) -> bool {
         self.inter_expr().eq_path_segments(left, right)
     }
+
+    pub fn eq_modifiers(&mut self, left: TraitBoundModifiers, right: TraitBoundModifiers) -> bool {
+        std::mem::discriminant(&left.constness) == std::mem::discriminant(&right.constness)
+            && std::mem::discriminant(&left.polarity) == std::mem::discriminant(&right.polarity)
+    }
 }
 
 pub struct HirEqInterExpr<'a, 'b, 'tcx> {
@@ -1143,6 +1149,12 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
         }
     }
 
+    pub fn hash_modifiers(&mut self, modifiers: TraitBoundModifiers) {
+        let TraitBoundModifiers { constness, polarity } = modifiers;
+        std::mem::discriminant(&polarity).hash(&mut self.s);
+        std::mem::discriminant(&constness).hash(&mut self.s);
+    }
+
     pub fn hash_stmt(&mut self, b: &Stmt<'_>) {
         std::mem::discriminant(&b.kind).hash(&mut self.s);