Auto merge of #108340 - eggyal:remove_traversal_trait_aliases, r=oli-obk

Remove type-traversal trait aliases

#107924 moved the type traversal (folding and visiting) traits into the type library, but created trait aliases in `rustc_middle` to minimise both the API churn for trait consumers and the arising boilerplate.  As mentioned in that PR, an alternative approach of defining subtraits with blanket implementations of the respective supertraits was also considered at that time but was ruled out as not adding much value.

Unfortunately, it has since emerged that rust-analyzer has difficulty with these trait aliases at present, resulting in a degraded contributor experience (see the recent [r-a has become useless](https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/r-a.20has.20become.20useless) topic on the #t-compiler/help Zulip stream).

This PR removes the trait aliases, and accordingly the underlying type library traits are now used directly; they are parameterised by `TyCtxt<'tcx>` rather than just the `'tcx` lifetime, and imports have been updated to reflect the fact that the trait aliases' explicitly named traits are no longer automatically brought into scope.  These changes also roll-back the (no-longer required) workarounds to #107747 that were made in b409329c62.

Since this PR is just a find+replace together with the changes necessary for compilation & tidy to pass, it's currently just one mega-commit.  Let me know if you'd like it broken up.

r? `@oli-obk`

clippy_lints/src/dereference.rs

@@ -27,7 +27,7 @@ use rustc_middle::mir::{Rvalue, StatementKind};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
 use rustc_middle::ty::{
     self, Binder, BoundVariableKind, Clause, EarlyBinder, FnSig, GenericArgKind, List, ParamTy, PredicateKind,
-    ProjectionPredicate, Ty, TyCtxt, TypeVisitable, TypeckResults,
+    ProjectionPredicate, Ty, TyCtxt, TypeVisitableExt, TypeckResults,
 };
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::{symbol::sym, Span, Symbol};

clippy_lints/src/eta_reduction.rs

@@ -11,7 +11,7 @@ use rustc_hir::{Closure, Expr, ExprKind, Param, PatKind, Unsafety};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
 use rustc_middle::ty::binding::BindingMode;
-use rustc_middle::ty::{self, EarlyBinder, SubstsRef, Ty, TypeVisitable};
+use rustc_middle::ty::{self, EarlyBinder, SubstsRef, Ty, TypeVisitableExt};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::sym;
 

clippy_lints/src/mut_key.rs

@@ -3,7 +3,7 @@ use clippy_utils::{def_path_def_ids, trait_ref_of_method};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::TypeVisitable;
+use rustc_middle::ty::TypeVisitableExt;
 use rustc_middle::ty::{Adt, Array, Ref, Slice, Tuple, Ty};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::def_id::LocalDefId;

clippy_lints/src/needless_pass_by_value.rs

@@ -18,7 +18,7 @@ use rustc_hir_typeck::expr_use_visitor as euv;
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::mir::FakeReadCause;
-use rustc_middle::ty::{self, TypeVisitable};
+use rustc_middle::ty::{self, TypeVisitableExt};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::symbol::kw;

clippy_lints/src/transmute/transmute_ptr_to_ref.rs

@@ -6,7 +6,7 @@ use clippy_utils::sugg;
 use rustc_errors::Applicability;
 use rustc_hir::{self as hir, Expr, GenericArg, Mutability, Path, TyKind};
 use rustc_lint::LateContext;
-use rustc_middle::ty::{self, Ty, TypeVisitable};
+use rustc_middle::ty::{self, Ty, TypeVisitableExt};
 
 /// Checks for `transmute_ptr_to_ref` lint.
 /// Returns `true` if it's triggered, otherwise returns `false`.

clippy_lints/src/transmute/useless_transmute.rs

@@ -4,7 +4,7 @@ use clippy_utils::sugg;
 use rustc_errors::Applicability;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
-use rustc_middle::ty::{self, Ty, TypeVisitable};
+use rustc_middle::ty::{self, Ty, TypeVisitableExt};
 
 /// Checks for `useless_transmute` lint.
 /// Returns `true` if it's triggered, otherwise returns `false`.

clippy_lints/src/types/redundant_allocation.rs

@@ -5,7 +5,7 @@ use rustc_errors::Applicability;
 use rustc_hir::{self as hir, def_id::DefId, QPath, TyKind};
 use rustc_hir_analysis::hir_ty_to_ty;
 use rustc_lint::LateContext;
-use rustc_middle::ty::TypeVisitable;
+use rustc_middle::ty::TypeVisitableExt;
 use rustc_span::symbol::sym;
 
 use super::{utils, REDUNDANT_ALLOCATION};

clippy_lints/src/types/vec_box.rs

@@ -7,7 +7,7 @@ use rustc_hir::{self as hir, def_id::DefId, GenericArg, QPath, TyKind};
 use rustc_hir_analysis::hir_ty_to_ty;
 use rustc_lint::LateContext;
 use rustc_middle::ty::layout::LayoutOf;
-use rustc_middle::ty::TypeVisitable;
+use rustc_middle::ty::TypeVisitableExt;
 use rustc_span::symbol::sym;
 
 use super::VEC_BOX;

clippy_lints/src/zero_sized_map_values.rs

@@ -5,7 +5,7 @@ use rustc_hir::{self as hir, HirId, ItemKind, Node};
 use rustc_hir_analysis::hir_ty_to_ty;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::layout::LayoutOf as _;
-use rustc_middle::ty::{Adt, Ty, TypeVisitable};
+use rustc_middle::ty::{Adt, Ty, TypeVisitableExt};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 

clippy_utils/src/lib.rs

@@ -104,7 +104,7 @@ use rustc_middle::ty::fast_reject::SimplifiedType::{
     PtrSimplifiedType, SliceSimplifiedType, StrSimplifiedType, UintSimplifiedType,
 };
 use rustc_middle::ty::{
-    layout::IntegerExt, BorrowKind, ClosureKind, DefIdTree, Ty, TyCtxt, TypeAndMut, TypeVisitable, UpvarCapture,
+    layout::IntegerExt, BorrowKind, ClosureKind, DefIdTree, Ty, TyCtxt, TypeAndMut, TypeVisitableExt, UpvarCapture,
 };
 use rustc_middle::ty::{FloatTy, IntTy, UintTy};
 use rustc_span::hygiene::{ExpnKind, MacroKind};

clippy_utils/src/mir/possible_borrower.rs

@@ -4,7 +4,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_index::bit_set::{BitSet, HybridBitSet};
 use rustc_lint::LateContext;
 use rustc_middle::mir::{self, visit::Visitor as _, Mutability};
-use rustc_middle::ty::{self, visit::ir::TypeVisitor, TyCtxt};
+use rustc_middle::ty::{self, visit::TypeVisitor, TyCtxt};
 use rustc_mir_dataflow::{impls::MaybeStorageLive, Analysis, ResultsCursor};
 use std::borrow::Cow;
 use std::ops::ControlFlow;

clippy_utils/src/ty.rs

@@ -17,8 +17,8 @@ use rustc_lint::LateContext;
 use rustc_middle::mir::interpret::{ConstValue, Scalar};
 use rustc_middle::ty::{
     self, AdtDef, AliasTy, AssocKind, Binder, BoundRegion, DefIdTree, FnSig, IntTy, List, ParamEnv, Predicate,
-    PredicateKind, Region, RegionKind, SubstsRef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, ir::TypeVisitor, UintTy,
-    VariantDef, VariantDiscr,
+    PredicateKind, Region, RegionKind, SubstsRef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor, UintTy,
+    VariantDef, VariantDiscr, TypeVisitableExt,
 };
 use rustc_middle::ty::{GenericArg, GenericArgKind};
 use rustc_span::symbol::Ident;
@@ -847,7 +847,7 @@ pub fn for_each_top_level_late_bound_region<B>(
                 ControlFlow::Continue(())
             }
         }
-        fn visit_binder<T: TypeVisitable<'tcx>>(&mut self, t: &Binder<'tcx, T>) -> ControlFlow<Self::BreakTy> {
+        fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(&mut self, t: &Binder<'tcx, T>) -> ControlFlow<Self::BreakTy> {
             self.index += 1;
             let res = t.super_visit_with(self);
             self.index -= 1;