Auto merge of #104846 - spastorino:santa-clauses-make-goals-early-christmas-🎄, r=oli-obk

Branch Clause from Predicate

r? `@oli-obk`

This is part of what's proposed in https://github.com/rust-lang/compiler-team/issues/531

10 files changed, 34 insertions, 35 deletions

diff --git a/clippy_lints/src/dereference.rs b/clippy_lints/src/dereference.rs
index 18e742a85b3..47ea98956be 100644
--- a/clippy_lints/src/dereference.rs
+++ b/clippy_lints/src/dereference.rs
@@ -25,7 +25,7 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::mir::{Rvalue, StatementKind};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
 use rustc_middle::ty::{
-    self, Binder, BoundVariableKind, EarlyBinder, FnSig, GenericArgKind, List, ParamTy, PredicateKind,
+    self, Binder, BoundVariableKind, Clause, EarlyBinder, FnSig, GenericArgKind, List, ParamTy, PredicateKind,
     ProjectionPredicate, Ty, TyCtxt, TypeVisitable, TypeckResults,
 };
 use rustc_semver::RustcVersion;
@@ -1097,7 +1097,7 @@ fn needless_borrow_impl_arg_position<'tcx>(
     let projection_predicates = predicates
         .iter()
         .filter_map(|predicate| {
-            if let PredicateKind::Projection(projection_predicate) = predicate.kind().skip_binder() {
+            if let PredicateKind::Clause(Clause::Projection(projection_predicate)) = predicate.kind().skip_binder() {
                 Some(projection_predicate)
             } else {
                 None
@@ -1111,7 +1111,7 @@ fn needless_borrow_impl_arg_position<'tcx>(
     if predicates
         .iter()
         .filter_map(|predicate| {
-            if let PredicateKind::Trait(trait_predicate) = predicate.kind().skip_binder()
+            if let PredicateKind::Clause(Clause::Trait(trait_predicate)) = predicate.kind().skip_binder()
                 && trait_predicate.trait_ref.self_ty() == param_ty.to_ty(cx.tcx)
             {
                 Some(trait_predicate.trait_ref.def_id)
@@ -1173,7 +1173,7 @@ fn needless_borrow_impl_arg_position<'tcx>(
         }
 
         predicates.iter().all(|predicate| {
-            if let PredicateKind::Trait(trait_predicate) = predicate.kind().skip_binder()
+            if let PredicateKind::Clause(Clause::Trait(trait_predicate)) = predicate.kind().skip_binder()
                 && cx.tcx.is_diagnostic_item(sym::IntoIterator, trait_predicate.trait_ref.def_id)
                 && let ty::Param(param_ty) = trait_predicate.self_ty().kind()
                 && let GenericArgKind::Type(ty) = substs_with_referent_ty[param_ty.index as usize].unpack()
diff --git a/clippy_lints/src/derive.rs b/clippy_lints/src/derive.rs
index 1d9af7cdbd3..d870e0ceef4 100644
--- a/clippy_lints/src/derive.rs
+++ b/clippy_lints/src/derive.rs
@@ -14,7 +14,7 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::traits::Reveal;
 use rustc_middle::ty::{
-    self, Binder, BoundConstness, GenericParamDefKind, ImplPolarity, ParamEnv, PredicateKind, TraitPredicate, TraitRef,
+    self, Binder, BoundConstness, Clause, GenericParamDefKind, ImplPolarity, ParamEnv, PredicateKind, TraitPredicate, TraitRef,
     Ty, TyCtxt,
 };
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -499,7 +499,7 @@ fn param_env_for_derived_eq(tcx: TyCtxt<'_>, did: DefId, eq_trait_id: DefId) ->
 
     let ty_predicates = tcx.predicates_of(did).predicates;
     for (p, _) in ty_predicates {
-        if let PredicateKind::Trait(p) = p.kind().skip_binder()
+        if let PredicateKind::Clause(Clause::Trait(p)) = p.kind().skip_binder()
             && p.trait_ref.def_id == eq_trait_id
             && let ty::Param(self_ty) = p.trait_ref.self_ty().kind()
             && p.constness == BoundConstness::NotConst
@@ -512,14 +512,14 @@ fn param_env_for_derived_eq(tcx: TyCtxt<'_>, did: DefId, eq_trait_id: DefId) ->
     ParamEnv::new(
         tcx.mk_predicates(ty_predicates.iter().map(|&(p, _)| p).chain(
             params.iter().filter(|&&(_, needs_eq)| needs_eq).map(|&(param, _)| {
-                tcx.mk_predicate(Binder::dummy(PredicateKind::Trait(TraitPredicate {
+                tcx.mk_predicate(Binder::dummy(PredicateKind::Clause(Clause::Trait(TraitPredicate {
                     trait_ref: TraitRef::new(
                         eq_trait_id,
                         tcx.mk_substs(std::iter::once(tcx.mk_param_from_def(param))),
                     ),
                     constness: BoundConstness::NotConst,
                     polarity: ImplPolarity::Positive,
-                })))
+                }))))
             }),
         )),
         Reveal::UserFacing,
diff --git a/clippy_lints/src/future_not_send.rs b/clippy_lints/src/future_not_send.rs
index 0519f9ac246..a9425a40f88 100644
--- a/clippy_lints/src/future_not_send.rs
+++ b/clippy_lints/src/future_not_send.rs
@@ -4,7 +4,7 @@ use rustc_hir::intravisit::FnKind;
 use rustc_hir::{Body, FnDecl, HirId};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::{EarlyBinder, Opaque, PredicateKind::Trait};
+use rustc_middle::ty::{Clause, EarlyBinder, Opaque, PredicateKind};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{sym, Span};
 use rustc_trait_selection::traits::error_reporting::suggestions::TypeErrCtxtExt;
@@ -91,7 +91,7 @@ impl<'tcx> LateLintPass<'tcx> for FutureNotSend {
                                 infcx
                                     .err_ctxt()
                                     .maybe_note_obligation_cause_for_async_await(db, &obligation);
-                                if let Trait(trait_pred) = obligation.predicate.kind().skip_binder() {
+                                if let PredicateKind::Clause(Clause::Trait(trait_pred)) = obligation.predicate.kind().skip_binder() {
                                     db.note(&format!(
                                         "`{}` doesn't implement `{}`",
                                         trait_pred.self_ty(),
diff --git a/clippy_lints/src/methods/unnecessary_to_owned.rs b/clippy_lints/src/methods/unnecessary_to_owned.rs
index 8b000cd754c..7ff13b95626 100644
--- a/clippy_lints/src/methods/unnecessary_to_owned.rs
+++ b/clippy_lints/src/methods/unnecessary_to_owned.rs
@@ -17,7 +17,7 @@ use rustc_middle::mir::Mutability;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, OverloadedDeref};
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind, SubstsRef};
 use rustc_middle::ty::EarlyBinder;
-use rustc_middle::ty::{self, ParamTy, PredicateKind, ProjectionPredicate, TraitPredicate, Ty};
+use rustc_middle::ty::{self, Clause, ParamTy, PredicateKind, ProjectionPredicate, TraitPredicate, Ty};
 use rustc_semver::RustcVersion;
 use rustc_span::{sym, Symbol};
 use rustc_trait_selection::traits::{
@@ -341,12 +341,12 @@ fn get_input_traits_and_projections<'tcx>(
     let mut projection_predicates = Vec::new();
     for predicate in cx.tcx.param_env(callee_def_id).caller_bounds() {
         match predicate.kind().skip_binder() {
-            PredicateKind::Trait(trait_predicate) => {
+            PredicateKind::Clause(Clause::Trait(trait_predicate)) => {
                 if trait_predicate.trait_ref.self_ty() == input {
                     trait_predicates.push(trait_predicate);
                 }
             }
-            PredicateKind::Projection(projection_predicate) => {
+            PredicateKind::Clause(Clause::Projection(projection_predicate)) => {
                 if projection_predicate.projection_ty.self_ty() == input {
                     projection_predicates.push(projection_predicate);
                 }
@@ -403,7 +403,7 @@ fn can_change_type<'a>(cx: &LateContext<'a>, mut expr: &'a Expr<'a>, mut ty: Ty<
 
                         let mut trait_predicates = cx.tcx.param_env(callee_def_id)
                             .caller_bounds().iter().filter(|predicate| {
-                            if let PredicateKind::Trait(trait_predicate) =  predicate.kind().skip_binder()
+                            if let PredicateKind::Clause(Clause::Trait(trait_predicate)) =  predicate.kind().skip_binder()
                                 && trait_predicate.trait_ref.self_ty() == *param_ty {
                                     true
                                 } else {
diff --git a/clippy_lints/src/needless_pass_by_value.rs b/clippy_lints/src/needless_pass_by_value.rs
index 55599cd03eb..75e12715458 100644
--- a/clippy_lints/src/needless_pass_by_value.rs
+++ b/clippy_lints/src/needless_pass_by_value.rs
@@ -124,7 +124,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByValue {
             .filter_map(|obligation| {
                 // Note that we do not want to deal with qualified predicates here.
                 match obligation.predicate.kind().no_bound_vars() {
-                    Some(ty::PredicateKind::Trait(pred)) if pred.def_id() != sized_trait => Some(pred),
+                    Some(ty::PredicateKind::Clause(ty::Clause::Trait(pred))) if pred.def_id() != sized_trait => Some(pred),
                     _ => None,
                 }
             })
diff --git a/clippy_lints/src/ptr.rs b/clippy_lints/src/ptr.rs
index 5420a0e782e..d28e97b7943 100644
--- a/clippy_lints/src/ptr.rs
+++ b/clippy_lints/src/ptr.rs
@@ -19,7 +19,7 @@ use rustc_infer::infer::TyCtxtInferExt;
 use rustc_infer::traits::{Obligation, ObligationCause};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter;
-use rustc_middle::ty::{self, Binder, ExistentialPredicate, List, PredicateKind, Ty};
+use rustc_middle::ty::{self, Binder, Clause, ExistentialPredicate, List, PredicateKind, Ty};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
 use rustc_span::sym;
@@ -698,9 +698,8 @@ fn matches_preds<'tcx>(
             cx.tcx,
             ObligationCause::dummy(),
             cx.param_env,
-            cx.tcx.mk_predicate(Binder::bind_with_vars(
-                PredicateKind::Projection(p.with_self_ty(cx.tcx, ty)),
-                List::empty(),
+            cx.tcx.mk_predicate(Binder::dummy(
+                PredicateKind::Clause(Clause::Projection(p.with_self_ty(cx.tcx, ty))),
             )),
         )),
         ExistentialPredicate::AutoTrait(p) => infcx
diff --git a/clippy_lints/src/unit_return_expecting_ord.rs b/clippy_lints/src/unit_return_expecting_ord.rs
index 1307288623f..a138a4baa9b 100644
--- a/clippy_lints/src/unit_return_expecting_ord.rs
+++ b/clippy_lints/src/unit_return_expecting_ord.rs
@@ -4,7 +4,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::{Closure, Expr, ExprKind, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
-use rustc_middle::ty::{GenericPredicates, PredicateKind, ProjectionPredicate, TraitPredicate};
+use rustc_middle::ty::{Clause, GenericPredicates, PredicateKind, ProjectionPredicate, TraitPredicate};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{sym, BytePos, Span};
 
@@ -45,7 +45,7 @@ fn get_trait_predicates_for_trait_id<'tcx>(
     let mut preds = Vec::new();
     for (pred, _) in generics.predicates {
         if_chain! {
-            if let PredicateKind::Trait(poly_trait_pred) = pred.kind().skip_binder();
+            if let PredicateKind::Clause(Clause::Trait(poly_trait_pred)) = pred.kind().skip_binder();
             let trait_pred = cx.tcx.erase_late_bound_regions(pred.kind().rebind(poly_trait_pred));
             if let Some(trait_def_id) = trait_id;
             if trait_def_id == trait_pred.trait_ref.def_id;
@@ -63,7 +63,7 @@ fn get_projection_pred<'tcx>(
     trait_pred: TraitPredicate<'tcx>,
 ) -> Option<ProjectionPredicate<'tcx>> {
     generics.predicates.iter().find_map(|(proj_pred, _)| {
-        if let ty::PredicateKind::Projection(pred) = proj_pred.kind().skip_binder() {
+        if let ty::PredicateKind::Clause(Clause::Projection(pred)) = proj_pred.kind().skip_binder() {
             let projection_pred = cx.tcx.erase_late_bound_regions(proj_pred.kind().rebind(pred));
             if projection_pred.projection_ty.substs == trait_pred.trait_ref.substs {
                 return Some(projection_pred);
diff --git a/clippy_utils/src/eager_or_lazy.rs b/clippy_utils/src/eager_or_lazy.rs
index 95b3e651e2b..f74f7dadfa9 100644
--- a/clippy_utils/src/eager_or_lazy.rs
+++ b/clippy_utils/src/eager_or_lazy.rs
@@ -73,7 +73,7 @@ fn fn_eagerness(cx: &LateContext<'_>, fn_id: DefId, name: Symbol, have_one_arg:
             .flat_map(|v| v.fields.iter())
             .any(|x| matches!(cx.tcx.type_of(x.did).peel_refs().kind(), ty::Param(_)))
             && all_predicates_of(cx.tcx, fn_id).all(|(pred, _)| match pred.kind().skip_binder() {
-                PredicateKind::Trait(pred) => cx.tcx.trait_def(pred.trait_ref.def_id).is_marker,
+                PredicateKind::Clause(ty::Clause::Trait(pred)) => cx.tcx.trait_def(pred.trait_ref.def_id).is_marker,
                 _ => true,
             })
             && subs.types().all(|x| matches!(x.peel_refs().kind(), ty::Param(_)))
diff --git a/clippy_utils/src/qualify_min_const_fn.rs b/clippy_utils/src/qualify_min_const_fn.rs
index d183e28f667..b8c2dd5ab9e 100644
--- a/clippy_utils/src/qualify_min_const_fn.rs
+++ b/clippy_utils/src/qualify_min_const_fn.rs
@@ -25,13 +25,13 @@ pub fn is_min_const_fn<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, msrv: Option<
         let predicates = tcx.predicates_of(current);
         for (predicate, _) in predicates.predicates {
             match predicate.kind().skip_binder() {
-                ty::PredicateKind::RegionOutlives(_)
-                | ty::PredicateKind::TypeOutlives(_)
+                ty::PredicateKind::Clause(ty::Clause::RegionOutlives(_))
+                | ty::PredicateKind::Clause(ty::Clause::TypeOutlives(_))
                 | ty::PredicateKind::WellFormed(_)
-                | ty::PredicateKind::Projection(_)
+                | ty::PredicateKind::Clause(ty::Clause::Projection(_))
                 | ty::PredicateKind::ConstEvaluatable(..)
                 | ty::PredicateKind::ConstEquate(..)
-                | ty::PredicateKind::Trait(..)
+                | ty::PredicateKind::Clause(ty::Clause::Trait(..))
                 | ty::PredicateKind::TypeWellFormedFromEnv(..) => continue,
                 ty::PredicateKind::ObjectSafe(_) => panic!("object safe predicate on function: {predicate:#?}"),
                 ty::PredicateKind::ClosureKind(..) => panic!("closure kind predicate on function: {predicate:#?}"),
diff --git a/clippy_utils/src/ty.rs b/clippy_utils/src/ty.rs
index 8284dc5c28c..f4459e3e663 100644
--- a/clippy_utils/src/ty.rs
+++ b/clippy_utils/src/ty.rs
@@ -81,7 +81,7 @@ pub fn contains_ty_adt_constructor_opaque<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'
                     match predicate.kind().skip_binder() {
                         // For `impl Trait<U>`, it will register a predicate of `T: Trait<U>`, so we go through
                         // and check substituions to find `U`.
-                        ty::PredicateKind::Trait(trait_predicate) => {
+                        ty::PredicateKind::Clause(ty::Clause::Trait(trait_predicate)) => {
                             if trait_predicate
                                 .trait_ref
                                 .substs
@@ -94,7 +94,7 @@ pub fn contains_ty_adt_constructor_opaque<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'
                         },
                         // For `impl Trait<Assoc=U>`, it will register a predicate of `<T as Trait>::Assoc = U`,
                         // so we check the term for `U`.
-                        ty::PredicateKind::Projection(projection_predicate) => {
+                        ty::PredicateKind::Clause(ty::Clause::Projection(projection_predicate)) => {
                             if let ty::TermKind::Ty(ty) = projection_predicate.term.unpack() {
                                 if contains_ty_adt_constructor_opaque(cx, ty, needle) {
                                     return true;
@@ -239,7 +239,7 @@ pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
         ty::Tuple(substs) => substs.iter().any(|ty| is_must_use_ty(cx, ty)),
         ty::Opaque(def_id, _) => {
             for (predicate, _) in cx.tcx.explicit_item_bounds(*def_id) {
-                if let ty::PredicateKind::Trait(trait_predicate) = predicate.kind().skip_binder() {
+                if let ty::PredicateKind::Clause(ty::Clause::Trait(trait_predicate)) = predicate.kind().skip_binder() {
                     if cx.tcx.has_attr(trait_predicate.trait_ref.def_id, sym::must_use) {
                         return true;
                     }
@@ -658,7 +658,7 @@ fn sig_from_bounds<'tcx>(
 
     for pred in predicates {
         match pred.kind().skip_binder() {
-            PredicateKind::Trait(p)
+            PredicateKind::Clause(ty::Clause::Trait(p))
                 if (lang_items.fn_trait() == Some(p.def_id())
                     || lang_items.fn_mut_trait() == Some(p.def_id())
                     || lang_items.fn_once_trait() == Some(p.def_id()))
@@ -671,7 +671,7 @@ fn sig_from_bounds<'tcx>(
                 }
                 inputs = Some(i);
             },
-            PredicateKind::Projection(p)
+            PredicateKind::Clause(ty::Clause::Projection(p))
                 if Some(p.projection_ty.item_def_id) == lang_items.fn_once_output()
                     && p.projection_ty.self_ty() == ty =>
             {
@@ -699,7 +699,7 @@ fn sig_for_projection<'tcx>(cx: &LateContext<'tcx>, ty: ProjectionTy<'tcx>) -> O
         .subst_iter_copied(cx.tcx, ty.substs)
     {
         match pred.kind().skip_binder() {
-            PredicateKind::Trait(p)
+            PredicateKind::Clause(ty::Clause::Trait(p))
                 if (lang_items.fn_trait() == Some(p.def_id())
                     || lang_items.fn_mut_trait() == Some(p.def_id())
                     || lang_items.fn_once_trait() == Some(p.def_id())) =>
@@ -712,7 +712,7 @@ fn sig_for_projection<'tcx>(cx: &LateContext<'tcx>, ty: ProjectionTy<'tcx>) -> O
                 }
                 inputs = Some(i);
             },
-            PredicateKind::Projection(p) if Some(p.projection_ty.item_def_id) == lang_items.fn_once_output() => {
+            PredicateKind::Clause(ty::Clause::Projection(p)) if Some(p.projection_ty.item_def_id) == lang_items.fn_once_output() => {
                 if output.is_some() {
                     // Multiple different fn trait impls. Is this even allowed?
                     return None;
@@ -887,7 +887,7 @@ pub fn ty_is_fn_once_param<'tcx>(tcx: TyCtxt<'_>, ty: Ty<'tcx>, predicates: &'tc
     predicates
         .iter()
         .try_fold(false, |found, p| {
-            if let PredicateKind::Trait(p) = p.kind().skip_binder()
+            if let PredicateKind::Clause(ty::Clause::Trait(p)) = p.kind().skip_binder()
             && let ty::Param(self_ty) = p.trait_ref.self_ty().kind()
             && ty.index == self_ty.index
         {