Auto merge of #80679 - jackh726:predicate-kind-take2, r=lcnr

Remove PredicateKind and instead only use Binder<PredicateAtom>

Originally brought up in https://github.com/rust-lang/rust/pull/76814#discussion_r546858171

r? `@lcnr`

6 files changed, 24 insertions, 26 deletions

diff --git a/src/tools/clippy/clippy_lints/src/future_not_send.rs b/src/tools/clippy/clippy_lints/src/future_not_send.rs
index f9697afe405..a3a38fad9a3 100644
--- a/src/tools/clippy/clippy_lints/src/future_not_send.rs
+++ b/src/tools/clippy/clippy_lints/src/future_not_send.rs
@@ -4,7 +4,7 @@ use rustc_hir::{Body, FnDecl, HirId};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::subst::Subst;
-use rustc_middle::ty::{Opaque, PredicateAtom::Trait};
+use rustc_middle::ty::{Opaque, PredicateKind::Trait};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{sym, Span};
 use rustc_trait_selection::traits::error_reporting::suggestions::InferCtxtExt;
@@ -97,7 +97,7 @@ impl<'tcx> LateLintPass<'tcx> for FutureNotSend {
                                         &obligation,
                                     );
                                     if let Trait(trait_pred, _) =
-                                        obligation.predicate.skip_binders()
+                                        obligation.predicate.kind().skip_binder()
                                     {
                                         db.note(&format!(
                                             "`{}` doesn't implement `{}`",
diff --git a/src/tools/clippy/clippy_lints/src/methods/mod.rs b/src/tools/clippy/clippy_lints/src/methods/mod.rs
index 6e8102790a5..f7231bba175 100644
--- a/src/tools/clippy/clippy_lints/src/methods/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/mod.rs
@@ -1697,7 +1697,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
             if let ty::Opaque(def_id, _) = *ret_ty.kind() {
                 // one of the associated types must be Self
                 for &(predicate, _span) in cx.tcx.explicit_item_bounds(def_id) {
-                    if let ty::PredicateAtom::Projection(projection_predicate) = predicate.skip_binders() {
+                    if let ty::PredicateKind::Projection(projection_predicate) = predicate.kind().skip_binder() {
                         // walk the associated type and check for Self
                         if contains_ty(projection_predicate.ty, self_ty) {
                             return;
diff --git a/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs b/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
index a435f86bfd8..3b71f1b46e2 100644
--- a/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
@@ -115,13 +115,11 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByValue {
             .filter(|p| !p.is_global())
             .filter_map(|obligation| {
                 // Note that we do not want to deal with qualified predicates here.
-                if let ty::PredicateKind::Atom(ty::PredicateAtom::Trait(pred, _)) = obligation.predicate.kind() {
-                    if pred.def_id() == sized_trait {
-                        return None;
-                    }
-                    Some(pred)
-                } else {
-                    None
+                match obligation.predicate.kind().no_bound_vars() {
+                    Some(ty::PredicateKind::Trait(pred, _)) if pred.def_id() != sized_trait => {
+                        Some(pred)
+                    },
+                    _ => None,
                 }
             })
             .collect::<Vec<_>>();
diff --git a/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs b/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs
index 2501635e7ef..c6ae8b9b598 100644
--- a/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs
+++ b/src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs
@@ -4,7 +4,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::{Expr, ExprKind, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
-use rustc_middle::ty::{GenericPredicates, PredicateAtom, ProjectionPredicate, TraitPredicate};
+use rustc_middle::ty::{GenericPredicates, PredicateKind, ProjectionPredicate, TraitPredicate};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{BytePos, Span};
 
@@ -42,7 +42,7 @@ fn get_trait_predicates_for_trait_id<'tcx>(
     let mut preds = Vec::new();
     for (pred, _) in generics.predicates {
         if_chain! {
-            if let PredicateAtom::Trait(poly_trait_pred, _) = pred.skip_binders();
+            if let PredicateKind::Trait(poly_trait_pred, _) = pred.kind().skip_binder();
             let trait_pred = cx.tcx.erase_late_bound_regions(ty::Binder::bind(poly_trait_pred));
             if let Some(trait_def_id) = trait_id;
             if trait_def_id == trait_pred.trait_ref.def_id;
@@ -60,7 +60,7 @@ fn get_projection_pred<'tcx>(
     pred: TraitPredicate<'tcx>,
 ) -> Option<ProjectionPredicate<'tcx>> {
     generics.predicates.iter().find_map(|(proj_pred, _)| {
-        if let ty::PredicateAtom::Projection(proj_pred) = proj_pred.skip_binders() {
+        if let ty::PredicateKind::Projection(proj_pred) = proj_pred.kind().skip_binder() {
             let projection_pred = cx.tcx.erase_late_bound_regions(ty::Binder::bind(proj_pred));
             if projection_pred.projection_ty.substs == pred.trait_ref.substs {
                 return Some(projection_pred);
diff --git a/src/tools/clippy/clippy_lints/src/utils/mod.rs b/src/tools/clippy/clippy_lints/src/utils/mod.rs
index 3e39a47f196..4c707c4b904 100644
--- a/src/tools/clippy/clippy_lints/src/utils/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/mod.rs
@@ -1470,7 +1470,7 @@ pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
         ty::Tuple(ref substs) => substs.types().any(|ty| is_must_use_ty(cx, ty)),
         ty::Opaque(ref def_id, _) => {
             for (predicate, _) in cx.tcx.explicit_item_bounds(*def_id) {
-                if let ty::PredicateAtom::Trait(trait_predicate, _) = predicate.skip_binders() {
+                if let ty::PredicateKind::Trait(trait_predicate, _) = predicate.kind().skip_binder() {
                     if must_use_attr(&cx.tcx.get_attrs(trait_predicate.trait_ref.def_id)).is_some() {
                         return true;
                     }
diff --git a/src/tools/clippy/clippy_lints/src/utils/qualify_min_const_fn.rs b/src/tools/clippy/clippy_lints/src/utils/qualify_min_const_fn.rs
index 7cb7d0a26b6..a482017afeb 100644
--- a/src/tools/clippy/clippy_lints/src/utils/qualify_min_const_fn.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/qualify_min_const_fn.rs
@@ -19,18 +19,18 @@ pub fn is_min_const_fn(tcx: TyCtxt<'tcx>, body: &'a Body<'tcx>) -> McfResult {
     loop {
         let predicates = tcx.predicates_of(current);
         for (predicate, _) in predicates.predicates {
-            match predicate.skip_binders() {
-                ty::PredicateAtom::RegionOutlives(_)
-                | ty::PredicateAtom::TypeOutlives(_)
-                | ty::PredicateAtom::WellFormed(_)
-                | ty::PredicateAtom::Projection(_)
-                | ty::PredicateAtom::ConstEvaluatable(..)
-                | ty::PredicateAtom::ConstEquate(..)
-                | ty::PredicateAtom::TypeWellFormedFromEnv(..) => continue,
-                ty::PredicateAtom::ObjectSafe(_) => panic!("object safe predicate on function: {:#?}", predicate),
-                ty::PredicateAtom::ClosureKind(..) => panic!("closure kind predicate on function: {:#?}", predicate),
-                ty::PredicateAtom::Subtype(_) => panic!("subtype predicate on function: {:#?}", predicate),
-                ty::PredicateAtom::Trait(pred, _) => {
+            match predicate.kind().skip_binder() {
+                ty::PredicateKind::RegionOutlives(_)
+                | ty::PredicateKind::TypeOutlives(_)
+                | ty::PredicateKind::WellFormed(_)
+                | ty::PredicateKind::Projection(_)
+                | ty::PredicateKind::ConstEvaluatable(..)
+                | ty::PredicateKind::ConstEquate(..)
+                | ty::PredicateKind::TypeWellFormedFromEnv(..) => continue,
+                ty::PredicateKind::ObjectSafe(_) => panic!("object safe predicate on function: {:#?}", predicate),
+                ty::PredicateKind::ClosureKind(..) => panic!("closure kind predicate on function: {:#?}", predicate),
+                ty::PredicateKind::Subtype(_) => panic!("subtype predicate on function: {:#?}", predicate),
+                ty::PredicateKind::Trait(pred, _) => {
                     if Some(pred.def_id()) == tcx.lang_items().sized_trait() {
                         continue;
                     }