Refactor where predicates, and reserve for attributes support

Author: frank-king

clippy_lints/src/extra_unused_type_parameters.rs

@@ -6,7 +6,7 @@ use rustc_errors::Applicability;
 use rustc_hir::intravisit::{Visitor, walk_impl_item, walk_item, walk_param_bound, walk_ty};
 use rustc_hir::{
     BodyId, ExprKind, GenericBound, GenericParam, GenericParamKind, Generics, ImplItem, ImplItemKind, Item, ItemKind,
-    PredicateOrigin, Ty, WherePredicate,
+    PredicateOrigin, Ty, WherePredicate, WherePredicateKind
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::nested_filter;
@@ -205,12 +205,13 @@ impl<'tcx> Visitor<'tcx> for TypeWalker<'_, 'tcx> {
     }
 
     fn visit_where_predicate(&mut self, predicate: &'tcx WherePredicate<'tcx>) {
-        if let WherePredicate::BoundPredicate(predicate) = predicate {
+        let span = predicate.span;
+        if let WherePredicateKind::BoundPredicate(predicate) = predicate.kind {
             // Collect spans for any bounds on type parameters.
             if let Some((def_id, _)) = predicate.bounded_ty.peel_refs().as_generic_param() {
                 match predicate.origin {
                     PredicateOrigin::GenericParam => {
-                        self.inline_bounds.insert(def_id, predicate.span);
+                        self.inline_bounds.insert(def_id, span);
                     },
                     PredicateOrigin::WhereClause => {
                         self.where_bounds.insert(def_id);

clippy_lints/src/implied_bounds_in_impls.rs

@@ -4,7 +4,7 @@ use rustc_errors::{Applicability, SuggestionStyle};
 use rustc_hir::def_id::DefId;
 use rustc_hir::{
     AssocItemConstraint, GenericArg, GenericBound, GenericBounds, PredicateOrigin, TraitBoundModifiers, TyKind,
-    WherePredicate,
+    WherePredicateKind,
 };
 use rustc_hir_analysis::lower_ty;
 use rustc_lint::{LateContext, LateLintPass};
@@ -324,7 +324,7 @@ fn check<'tcx>(cx: &LateContext<'tcx>, bounds: GenericBounds<'tcx>) {
 impl<'tcx> LateLintPass<'tcx> for ImpliedBoundsInImpls {
     fn check_generics(&mut self, cx: &LateContext<'tcx>, generics: &rustc_hir::Generics<'tcx>) {
         for predicate in generics.predicates {
-            if let WherePredicate::BoundPredicate(predicate) = predicate
+            if let WherePredicateKind::BoundPredicate(predicate) = predicate.kind
                 // In theory, the origin doesn't really matter,
                 // we *could* also lint on explicit where clauses written out by the user,
                 // not just impl trait desugared ones, but that contradicts with the lint name...

clippy_lints/src/lifetimes.rs

@@ -12,7 +12,7 @@ use rustc_hir::intravisit::{
 use rustc_hir::{
     BareFnTy, BodyId, FnDecl, FnSig, GenericArg, GenericArgs, GenericBound, GenericParam, GenericParamKind, Generics,
     Impl, ImplItem, ImplItemKind, Item, ItemKind, Lifetime, LifetimeName, LifetimeParamKind, Node, PolyTraitRef,
-    PredicateOrigin, TraitFn, TraitItem, TraitItemKind, Ty, TyKind, WherePredicate, lang_items,
+    PredicateOrigin, TraitFn, TraitItem, TraitItemKind, Ty, TyKind, WherePredicate, WherePredicateKind, lang_items,
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::map::Map;
@@ -442,9 +442,9 @@ impl<'tcx> Visitor<'tcx> for RefVisitor<'_, 'tcx> {
 /// reason about elision.
 fn has_where_lifetimes<'tcx>(cx: &LateContext<'tcx>, generics: &'tcx Generics<'_>) -> bool {
     for predicate in generics.predicates {
-        match *predicate {
-            WherePredicate::RegionPredicate(..) => return true,
-            WherePredicate::BoundPredicate(ref pred) => {
+        match *predicate.kind {
+            WherePredicateKind::RegionPredicate(..) => return true,
+            WherePredicateKind::BoundPredicate(ref pred) => {
                 // a predicate like F: Trait or F: for<'a> Trait<'a>
                 let mut visitor = RefVisitor::new(cx);
                 // walk the type F, it may not contain LT refs
@@ -467,7 +467,7 @@ fn has_where_lifetimes<'tcx>(cx: &LateContext<'tcx>, generics: &'tcx Generics<'_
                     }
                 }
             },
-            WherePredicate::EqPredicate(ref pred) => {
+            WherePredicateKind::EqPredicate(ref pred) => {
                 let mut visitor = RefVisitor::new(cx);
                 walk_ty(&mut visitor, pred.lhs_ty);
                 walk_ty(&mut visitor, pred.rhs_ty);

clippy_lints/src/multiple_bound_locations.rs

@@ -1,5 +1,5 @@
 use rustc_ast::visit::FnKind;
-use rustc_ast::{NodeId, WherePredicate};
+use rustc_ast::{NodeId, WherePredicateKind};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::declare_lint_pass;
@@ -51,8 +51,8 @@ impl EarlyLintPass for MultipleBoundLocations {
                 }
             }
             for clause in &generics.where_clause.predicates {
-                match clause {
-                    WherePredicate::BoundPredicate(pred) => {
+                match &clause.kind {
+                    WherePredicateKind::BoundPredicate(pred) => {
                         if (!pred.bound_generic_params.is_empty() || !pred.bounds.is_empty())
                             && let Some(Some(bound_span)) = pred
                                 .bounded_ty
@@ -62,14 +62,14 @@ impl EarlyLintPass for MultipleBoundLocations {
                             emit_lint(cx, *bound_span, pred.bounded_ty.span);
                         }
                     },
-                    WherePredicate::RegionPredicate(pred) => {
+                    WherePredicateKind::RegionPredicate(pred) => {
                         if !pred.bounds.is_empty()
                             && let Some(bound_span) = generic_params_with_bounds.get(&pred.lifetime.ident.name.as_str())
                         {
                             emit_lint(cx, *bound_span, pred.lifetime.ident.span);
                         }
                     },
-                    WherePredicate::EqPredicate(_) => {},
+                    WherePredicateKind::EqPredicate(_) => {},
                 }
             }
         }

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::{BoundPolarity, GenericBound, Generics, PolyTraitRef, TraitBoundModifiers, WherePredicate};
+use rustc_hir::{BoundPolarity, GenericBound, Generics, PolyTraitRef, TraitBoundModifiers, WherePredicateKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::{ClauseKind, PredicatePolarity};
 use rustc_session::declare_lint_pass;
@@ -52,7 +52,7 @@ fn type_param_bounds<'tcx>(generics: &'tcx Generics<'tcx>) -> impl Iterator<Item
         .iter()
         .enumerate()
         .filter_map(|(predicate_pos, predicate)| {
-            let WherePredicate::BoundPredicate(bound_predicate) = predicate else {
+            let WherePredicateKind::BoundPredicate(bound_predicate) = &predicate.kind else {
                 return None;
             };
 

clippy_lints/src/trait_bounds.rs

@@ -11,7 +11,7 @@ use rustc_errors::Applicability;
 use rustc_hir::def::Res;
 use rustc_hir::{
     BoundPolarity, GenericBound, Generics, Item, ItemKind, LangItem, Node, Path, PathSegment, PredicateOrigin, QPath,
-    TraitBoundModifiers, TraitItem, TraitRef, Ty, TyKind, WherePredicate,
+    TraitBoundModifiers, TraitItem, TraitRef, Ty, TyKind, WherePredicateKind,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::impl_lint_pass;
@@ -124,9 +124,9 @@ impl<'tcx> LateLintPass<'tcx> for TraitBounds {
         let mut self_bounds_map = FxHashMap::default();
 
         for predicate in item.generics.predicates {
-            if let WherePredicate::BoundPredicate(bound_predicate) = predicate
+            if let WherePredicateKind::BoundPredicate(bound_predicate) = predicate.kind
                 && bound_predicate.origin != PredicateOrigin::ImplTrait
-                && !bound_predicate.span.from_expansion()
+                && !predicate.span.from_expansion()
                 && let TyKind::Path(QPath::Resolved(_, Path { segments, .. })) = bound_predicate.bounded_ty.kind
                 && let Some(PathSegment {
                     res: Res::SelfTyParam { trait_: def_id },
@@ -268,10 +268,10 @@ impl TraitBounds {
         let mut map: UnhashMap<SpanlessTy<'_, '_>, Vec<&GenericBound<'_>>> = UnhashMap::default();
         let mut applicability = Applicability::MaybeIncorrect;
         for bound in generics.predicates {
-            if let WherePredicate::BoundPredicate(p) = bound
+            if let WherePredicateKind::BoundPredicate(p) = bound.kind
                 && p.origin != PredicateOrigin::ImplTrait
                 && p.bounds.len() as u64 <= self.max_trait_bounds
-                && !p.span.from_expansion()
+                && !bound.span.from_expansion()
                 && let bounds = p
                     .bounds
                     .iter()
@@ -295,7 +295,7 @@ impl TraitBounds {
                 span_lint_and_help(
                     cx,
                     TYPE_REPETITION_IN_BOUNDS,
-                    p.span,
+                    bound.span,
                     "this type has already been used as a bound predicate",
                     None,
                     hint_string,
@@ -322,8 +322,8 @@ fn check_trait_bound_duplication<'tcx>(cx: &LateContext<'tcx>, generics: &'_ Gen
         .predicates
         .iter()
         .filter_map(|pred| {
-            if pred.in_where_clause()
-                && let WherePredicate::BoundPredicate(bound_predicate) = pred
+            if pred.kind.in_where_clause()
+                && let WherePredicateKind::BoundPredicate(bound_predicate) = pred.kind
                 && let TyKind::Path(QPath::Resolved(_, path)) = bound_predicate.bounded_ty.kind
             {
                 return Some(
@@ -347,10 +347,10 @@ fn check_trait_bound_duplication<'tcx>(cx: &LateContext<'tcx>, generics: &'_ Gen
     //            |
     // compare trait bounds keyed by generic name and comparable trait to collected where
     // predicates eg. (T, Clone)
-    for predicate in generics.predicates.iter().filter(|pred| !pred.in_where_clause()) {
-        if let WherePredicate::BoundPredicate(bound_predicate) = predicate
+    for predicate in generics.predicates.iter().filter(|pred| !pred.kind.in_where_clause()) {
+        if let WherePredicateKind::BoundPredicate(bound_predicate) = predicate.kind
             && bound_predicate.origin != PredicateOrigin::ImplTrait
-            && !bound_predicate.span.from_expansion()
+            && !predicate.span.from_expansion()
             && let TyKind::Path(QPath::Resolved(_, path)) = bound_predicate.bounded_ty.kind
         {
             let traits = rollup_traits(cx, bound_predicate.bounds, "these bounds contain repeated elements");

clippy_utils/src/ast_utils.rs

@@ -661,8 +661,8 @@ pub fn eq_generics(l: &Generics, r: &Generics) -> bool {
 }
 
 pub fn eq_where_predicate(l: &WherePredicate, r: &WherePredicate) -> bool {
-    use WherePredicate::*;
-    match (l, r) {
+    use WherePredicateKind::*;
+    match (&l.kind, &r.kind) {
         (BoundPredicate(l), BoundPredicate(r)) => {
             over(&l.bound_generic_params, &r.bound_generic_params, |l, r| {
                 eq_generic_param(l, r)