remove TyS::same_type

it ignored regions and constants in adts,
but didn't do so for references or any other types.
This seemed quite weird

compiler/rustc_lint/src/builtin.rs

@@ -2833,7 +2833,7 @@ impl ClashingExternDeclarations {
                 return true;
             }
             let tcx = cx.tcx;
-            if a == b || rustc_middle::ty::TyS::same_type(a, b) {
+            if a == b {
                 // All nominally-same types are structurally same, too.
                 true
             } else {

compiler/rustc_middle/src/ty/util.rs

@@ -893,19 +893,6 @@ impl<'tcx> ty::TyS<'tcx> {
         }
     }
 
-    pub fn same_type(a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
-        match (&a.kind(), &b.kind()) {
-            (&Adt(did_a, substs_a), &Adt(did_b, substs_b)) => {
-                if did_a != did_b {
-                    return false;
-                }
-
-                substs_a.types().zip(substs_b.types()).all(|(a, b)| Self::same_type(a, b))
-            }
-            _ => a == b,
-        }
-    }
-
     /// Peel off all reference types in this type until there are none left.
     ///
     /// This method is idempotent, i.e. `ty.peel_refs().peel_refs() == ty.peel_refs()`.

compiler/rustc_mir_transform/src/function_item_references.rs

@@ -6,7 +6,7 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::{
     self,
     subst::{GenericArgKind, Subst, SubstsRef},
-    PredicateKind, Ty, TyCtxt, TyS,
+    PredicateKind, Ty, TyCtxt,
 };
 use rustc_session::lint::builtin::FUNCTION_ITEM_REFERENCES;
 use rustc_span::{symbol::sym, Span};
@@ -88,7 +88,7 @@ impl<'tcx> FunctionItemRefChecker<'_, 'tcx> {
                     for generic_inner_ty in arg_def.walk() {
                         if let GenericArgKind::Type(inner_ty) = generic_inner_ty.unpack() {
                             // If the inner type matches the type bound by `Pointer`
-                            if TyS::same_type(inner_ty, bound_ty) {
+                            if inner_ty == bound_ty {
                                 // Do a substitution using the parameters from the callsite
                                 let subst_ty = inner_ty.subst(self.tcx, substs_ref);
                                 if let Some((fn_id, fn_substs)) =

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1555,7 +1555,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
             // `erase_late_bound_regions`.
             let ty_erased = self.tcx.erase_late_bound_regions(ty);
             let ty_erased = self.tcx.erase_regions(ty_erased);
-            let eq = ty::TyS::same_type(ty_erased, target_ty_erased);
+            let eq = ty_erased == target_ty_erased;
             debug!(
                 "maybe_note_obligation_cause_for_async_await: ty_erased={:?} \
                     target_ty_erased={:?} eq={:?}",

compiler/rustc_ty_utils/src/representability.rs

@@ -322,7 +322,7 @@ fn is_type_structurally_recursive_inner<'tcx>(
                 // struct Foo { Option<Option<Foo>> }
 
                 for &seen_adt in iter {
-                    if ty::TyS::same_type(ty, seen_adt) {
+                    if ty == seen_adt {
                         debug!("ContainsRecursive: {:?} contains {:?}", seen_adt, ty);
                         return Representability::ContainsRecursive;
                     }

src/tools/clippy/clippy_lints/src/dereference.rs

@@ -12,7 +12,7 @@ use rustc_hir::{
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
-use rustc_middle::ty::{self, Ty, TyCtxt, TyS, TypeckResults};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeckResults};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::{symbol::sym, Span};
 
@@ -448,7 +448,7 @@ fn try_parse_ref_op<'tcx>(
 // the reference.
 fn deref_method_same_type(result_ty: Ty<'_>, arg_ty: Ty<'_>) -> bool {
     match (result_ty.kind(), arg_ty.kind()) {
-        (ty::Ref(_, result_ty, _), ty::Ref(_, arg_ty, _)) => TyS::same_type(result_ty, arg_ty),
+        (ty::Ref(_, result_ty, _), ty::Ref(_, arg_ty, _)) => result_ty == arg_ty,
 
         // The result type for a deref method is always a reference
         // Not matching the previous pattern means the argument type is not a reference

src/tools/clippy/clippy_lints/src/implicit_hasher.rs

@@ -8,7 +8,7 @@ use rustc_hir::{Body, Expr, ExprKind, GenericArg, Item, ItemKind, QPath, TyKind}
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty::{Ty, TyS, TypeckResults};
+use rustc_middle::ty::{Ty, TypeckResults};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
 use rustc_span::symbol::sym;
@@ -346,7 +346,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for ImplicitHasherConstructorVisitor<'a, 'b, 't
             if let TyKind::Path(QPath::Resolved(None, ty_path)) = ty.kind;
             if let Some(ty_did) = ty_path.res.opt_def_id();
             then {
-                if !TyS::same_type(self.target.ty(), self.maybe_typeck_results.unwrap().expr_ty(e)) {
+                if self.target.ty() != self.maybe_typeck_results.unwrap().expr_ty(e) {
                     return;
                 }
 

src/tools/clippy/clippy_lints/src/len_zero.rs

@@ -10,7 +10,7 @@ use rustc_hir::{
     ItemKind, Mutability, Node, TraitItemRef, TyKind,
 };
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::{self, AssocKind, FnSig, Ty, TyS};
+use rustc_middle::ty::{self, AssocKind, FnSig, Ty};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{
     source_map::{Span, Spanned, Symbol},
@@ -265,7 +265,7 @@ impl LenOutput<'_> {
             (_, &ty::Bool) => true,
             (Self::Option(id), &ty::Adt(adt, subs)) if id == adt.did => subs.type_at(0).is_bool(),
             (Self::Result(id, err_ty), &ty::Adt(adt, subs)) if id == adt.did => {
-                subs.type_at(0).is_bool() && TyS::same_type(subs.type_at(1), err_ty)
+                subs.type_at(0).is_bool() && subs.type_at(1) == err_ty
             },
             _ => false,
         }

src/tools/clippy/clippy_lints/src/loops/explicit_into_iter_loop.rs

@@ -5,13 +5,12 @@ use clippy_utils::source::snippet_with_applicability;
 use rustc_errors::Applicability;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
-use rustc_middle::ty::TyS;
 use rustc_span::symbol::sym;
 
 pub(super) fn check(cx: &LateContext<'_>, self_arg: &Expr<'_>, call_expr: &Expr<'_>) {
     let self_ty = cx.typeck_results().expr_ty(self_arg);
     let self_ty_adjusted = cx.typeck_results().expr_ty_adjusted(self_arg);
-    if !(TyS::same_type(self_ty, self_ty_adjusted) && is_trait_method(cx, call_expr, sym::IntoIterator)) {
+    if !(self_ty == self_ty_adjusted && is_trait_method(cx, call_expr, sym::IntoIterator)) {
         return;
     }
 

src/tools/clippy/clippy_lints/src/loops/explicit_iter_loop.rs

@@ -6,7 +6,7 @@ use clippy_utils::ty::is_type_diagnostic_item;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, Mutability};
 use rustc_lint::LateContext;
-use rustc_middle::ty::{self, Ty, TyS};
+use rustc_middle::ty::{self, Ty};
 use rustc_span::sym;
 
 pub(super) fn check(cx: &LateContext<'_>, self_arg: &Expr<'_>, arg: &Expr<'_>, method_name: &str) {
@@ -22,7 +22,7 @@ pub(super) fn check(cx: &LateContext<'_>, self_arg: &Expr<'_>, arg: &Expr<'_>, m
                     mutbl: Mutability::Not,
                 },
             );
-            TyS::same_type(receiver_ty_adjusted, ref_receiver_ty)
+            receiver_ty_adjusted == ref_receiver_ty
         },
         _ => false,
     };

src/tools/clippy/clippy_lints/src/matches.rs

@@ -26,7 +26,7 @@ use rustc_hir::{
 };
 use rustc_hir::{HirIdMap, HirIdSet};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::{self, Ty, TyS, VariantDef};
+use rustc_middle::ty::{self, Ty, VariantDef};
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::{Span, Spanned};
@@ -2262,7 +2262,7 @@ fn lint_match_arms<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>) {
                     };
                     // the names technically don't have to match; this makes the lint more conservative
                     if cx.tcx.hir().name(a_id) == cx.tcx.hir().name(b_id);
-                    if TyS::same_type(cx.typeck_results().expr_ty(a), cx.typeck_results().expr_ty(b));
+                    if cx.typeck_results().expr_ty(a) == cx.typeck_results().expr_ty(b);
                     if pat_contains_local(lhs.pat, a_id);
                     if pat_contains_local(rhs.pat, b_id);
                     then {

src/tools/clippy/clippy_lints/src/methods/filter_map.rs

@@ -8,7 +8,6 @@ use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::{Expr, ExprKind, PatKind, QPath, UnOp};
 use rustc_lint::LateContext;
-use rustc_middle::ty::TyS;
 use rustc_span::source_map::Span;
 use rustc_span::symbol::{sym, Symbol};
 use std::borrow::Cow;
@@ -149,7 +148,7 @@ pub(super) fn check<'tcx>(
                 if_chain! {
                     if path_to_local_id(a_path, filter_param_id);
                     if path_to_local_id(b, map_param_id);
-                    if TyS::same_type(cx.typeck_results().expr_ty_adjusted(a), cx.typeck_results().expr_ty_adjusted(b));
+                    if cx.typeck_results().expr_ty_adjusted(a) == cx.typeck_results().expr_ty_adjusted(b);
                     then {
                         return true;
                     }

src/tools/clippy/clippy_lints/src/methods/implicit_clone.rs

@@ -6,7 +6,6 @@ use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
-use rustc_middle::ty::TyS;
 use rustc_span::sym;
 
 use super::IMPLICIT_CLONE;
@@ -19,7 +18,7 @@ pub fn check(cx: &LateContext<'_>, method_name: &str, expr: &hir::Expr<'_>, recv
         let input_type = cx.typeck_results().expr_ty(recv);
         let (input_type, ref_count) = peel_mid_ty_refs(input_type);
         if let Some(ty_name) = input_type.ty_adt_def().map(|adt_def| cx.tcx.item_name(adt_def.did));
-        if TyS::same_type(return_type, input_type);
+        if return_type == input_type;
         then {
             let mut app = Applicability::MachineApplicable;
             let recv_snip = snippet_with_context(cx, recv.span, expr.span.ctxt(), "..", &mut app).0;

src/tools/clippy/clippy_lints/src/methods/mod.rs

@@ -78,7 +78,7 @@ use rustc_hir::def::Res;
 use rustc_hir::{Expr, ExprKind, PrimTy, QPath, TraitItem, TraitItemKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty::{self, TraitRef, Ty, TyS};
+use rustc_middle::ty::{self, TraitRef, Ty};
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::{sym, Span};
@@ -2195,7 +2195,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
                 }
             }
 
-            if name == "new" && !TyS::same_type(ret_ty, self_ty) {
+            if name == "new" && ret_ty != self_ty {
                 span_lint(
                     cx,
                     NEW_RET_NO_SELF,

src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs

@@ -5,7 +5,7 @@ use rustc_hir as hir;
 use rustc_hir::intravisit::{walk_expr, Visitor};
 use rustc_hir::LangItem::{OptionNone, OptionSome};
 use rustc_lint::LateContext;
-use rustc_middle::ty::{self, TyS};
+use rustc_middle::ty;
 use rustc_span::sym;
 
 use super::UNNECESSARY_FILTER_MAP;
@@ -34,7 +34,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr<
             let in_ty = cx.typeck_results().node_type(body.params[0].hir_id);
             match cx.typeck_results().expr_ty(&body.value).kind() {
                 ty::Adt(adt, subst)
-                    if cx.tcx.is_diagnostic_item(sym::Option, adt.did) && TyS::same_type(in_ty, subst.type_at(0)) =>
+                    if cx.tcx.is_diagnostic_item(sym::Option, adt.did) && in_ty == subst.type_at(0) =>
                 {
                     "filter"
                 },

src/tools/clippy/clippy_lints/src/needless_option_as_deref.rs

@@ -4,7 +4,6 @@ use clippy_utils::ty::is_type_diagnostic_item;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::TyS;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::sym;
 
@@ -49,7 +48,7 @@ impl<'tcx> LateLintPass<'tcx> for OptionNeedlessDeref {
             if let ExprKind::MethodCall(path, [sub_expr], _) = expr.kind;
             let symbol = path.ident.as_str();
             if symbol == "as_deref" || symbol == "as_deref_mut";
-            if TyS::same_type( outer_ty, typeck.expr_ty(sub_expr) );
+            if outer_ty == typeck.expr_ty(sub_expr);
             then{
                 span_lint_and_sugg(
                     cx,

src/tools/clippy/clippy_lints/src/needless_question_mark.rs

@@ -6,7 +6,6 @@ use rustc_errors::Applicability;
 use rustc_hir::LangItem::{OptionSome, ResultOk};
 use rustc_hir::{AsyncGeneratorKind, Block, Body, Expr, ExprKind, GeneratorKind, LangItem, MatchSource, QPath};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::TyS;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
@@ -128,7 +127,7 @@ fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
         if expr.span.ctxt() == inner_expr.span.ctxt();
         let expr_ty = cx.typeck_results().expr_ty(expr);
         let inner_ty = cx.typeck_results().expr_ty(inner_expr);
-        if TyS::same_type(expr_ty, inner_ty);
+        if expr_ty == inner_ty;
         then {
             span_lint_and_sugg(
                 cx,

src/tools/clippy/clippy_lints/src/new_without_default.rs

@@ -8,7 +8,6 @@ use rustc_hir as hir;
 use rustc_hir::HirIdSet;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty::TyS;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::sym;
 
@@ -103,7 +102,7 @@ impl<'tcx> LateLintPass<'tcx> for NewWithoutDefault {
                             if cx.access_levels.is_reachable(impl_item.def_id);
                             let self_def_id = cx.tcx.hir().get_parent_item(id);
                             let self_ty = cx.tcx.type_of(self_def_id);
-                            if TyS::same_type(self_ty, return_ty(cx, id));
+                            if self_ty == return_ty(cx, id);
                             if let Some(default_trait_id) = cx.tcx.get_diagnostic_item(sym::Default);
                             then {
                                 if self.impling_types.is_none() {

src/tools/clippy/clippy_lints/src/redundant_slicing.rs

@@ -6,7 +6,6 @@ use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{BorrowKind, Expr, ExprKind, LangItem, Mutability};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::TyS;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
@@ -54,7 +53,7 @@ impl<'tcx> LateLintPass<'tcx> for RedundantSlicing {
             if addressee.span.ctxt() == ctxt;
             if let ExprKind::Index(indexed, range) = addressee.kind;
             if is_type_lang_item(cx, cx.typeck_results().expr_ty_adjusted(range), LangItem::RangeFull);
-            if TyS::same_type(cx.typeck_results().expr_ty(expr), cx.typeck_results().expr_ty(indexed));
+            if cx.typeck_results().expr_ty(expr) == cx.typeck_results().expr_ty(indexed);
             then {
                 let mut app = Applicability::MachineApplicable;
                 let snip = snippet_with_context(cx, indexed.span, ctxt, "..", &mut app).0;

src/tools/clippy/clippy_lints/src/size_of_in_element_count.rs

@@ -7,7 +7,7 @@ use if_chain::if_chain;
 use rustc_hir::BinOpKind;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::{self, Ty, TyS, TypeAndMut};
+use rustc_middle::ty::{self, Ty, TypeAndMut};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
@@ -138,7 +138,7 @@ impl<'tcx> LateLintPass<'tcx> for SizeOfInElementCount {
             // Find a size_of call in the count parameter expression and
             // check that it's the same type
             if let Some(ty_used_for_size_of) = get_size_of_ty(cx, count_expr, false);
-            if TyS::same_type(pointee_ty, ty_used_for_size_of);
+            if pointee_ty == ty_used_for_size_of;
             then {
                 span_lint_and_help(
                     cx,

src/tools/clippy/clippy_utils/src/hir_utils.rs

@@ -102,7 +102,7 @@ impl HirEqInterExpr<'_, '_, '_> {
                 if let Some(typeck) = self.inner.maybe_typeck_results {
                     let l_ty = typeck.pat_ty(l.pat);
                     let r_ty = typeck.pat_ty(r.pat);
-                    if !rustc_middle::ty::TyS::same_type(l_ty, r_ty) {
+                    if l_ty != r_ty {
                         return false;
                     }
                 }

src/tools/clippy/clippy_utils/src/ty.rs

@@ -42,7 +42,7 @@ pub fn can_partially_move_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool
 /// Walks into `ty` and returns `true` if any inner type is the same as `other_ty`
 pub fn contains_ty(ty: Ty<'_>, other_ty: Ty<'_>) -> bool {
     ty.walk().any(|inner| match inner.unpack() {
-        GenericArgKind::Type(inner_ty) => ty::TyS::same_type(other_ty, inner_ty),
+        GenericArgKind::Type(inner_ty) => other_ty == inner_ty,
         GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
     })
 }