Rollup merge of #103603 - camsteffen:refactor-lang, r=oli-obk

Lang item cleanups

Various cleanups related to lang items.

13 files changed, 29 insertions, 39 deletions

diff --git a/src/tools/clippy/clippy_lints/src/lifetimes.rs b/src/tools/clippy/clippy_lints/src/lifetimes.rs
index 3bf2d7e4ea4..54c316358a1 100644
--- a/src/tools/clippy/clippy_lints/src/lifetimes.rs
+++ b/src/tools/clippy/clippy_lints/src/lifetimes.rs
@@ -6,11 +6,12 @@ use rustc_hir::intravisit::{
     walk_fn_decl, walk_generic_param, walk_generics, walk_impl_item_ref, walk_item, walk_param_bound,
     walk_poly_trait_ref, walk_trait_ref, walk_ty, Visitor,
 };
+use rustc_hir::lang_items;
 use rustc_hir::FnRetTy::Return;
 use rustc_hir::{
     BareFnTy, BodyId, FnDecl, GenericArg, GenericBound, GenericParam, GenericParamKind, Generics, Impl, ImplItem,
-    ImplItemKind, Item, ItemKind, LangItem, Lifetime, LifetimeName, ParamName, PolyTraitRef, PredicateOrigin, TraitFn,
-    TraitItem, TraitItemKind, Ty, TyKind, WherePredicate,
+    ImplItemKind, Item, ItemKind, Lifetime, LifetimeName, ParamName, PolyTraitRef, PredicateOrigin, TraitFn, TraitItem,
+    TraitItemKind, Ty, TyKind, WherePredicate,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter as middle_nested_filter;
@@ -364,8 +365,6 @@ fn unique_lifetimes(lts: &[RefLt]) -> usize {
     lts.iter().collect::<FxHashSet<_>>().len()
 }
 
-const CLOSURE_TRAIT_BOUNDS: [LangItem; 3] = [LangItem::Fn, LangItem::FnMut, LangItem::FnOnce];
-
 /// A visitor usable for `rustc_front::visit::walk_ty()`.
 struct RefVisitor<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
@@ -424,12 +423,8 @@ impl<'a, 'tcx> Visitor<'tcx> for RefVisitor<'a, 'tcx> {
 
     fn visit_poly_trait_ref(&mut self, poly_tref: &'tcx PolyTraitRef<'tcx>) {
         let trait_ref = &poly_tref.trait_ref;
-        if CLOSURE_TRAIT_BOUNDS.iter().any(|&item| {
-            self.cx
-                .tcx
-                .lang_items()
-                .require(item)
-                .map_or(false, |id| Some(id) == trait_ref.trait_def_id())
+        if let Some(id) = trait_ref.trait_def_id() && lang_items::FN_TRAITS.iter().any(|&item| {
+            self.cx.tcx.lang_items().get(item) == Some(id)
         }) {
             let mut sub_visitor = RefVisitor::new(self.cx);
             sub_visitor.visit_trait_ref(trait_ref);
diff --git a/src/tools/clippy/clippy_lints/src/manual_retain.rs b/src/tools/clippy/clippy_lints/src/manual_retain.rs
index 3181bc86d17..6abbab278fe 100644
--- a/src/tools/clippy/clippy_lints/src/manual_retain.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_retain.rs
@@ -92,7 +92,7 @@ fn check_into_iter(
         && match_def_path(cx, filter_def_id, &paths::CORE_ITER_FILTER)
         && let hir::ExprKind::MethodCall(_, struct_expr, [], _) = &into_iter_expr.kind
         && let Some(into_iter_def_id) = cx.typeck_results().type_dependent_def_id(into_iter_expr.hir_id)
-        && cx.tcx.lang_items().require(hir::LangItem::IntoIterIntoIter).ok() == Some(into_iter_def_id)
+        && Some(into_iter_def_id) == cx.tcx.lang_items().into_iter_fn()
         && match_acceptable_type(cx, left_expr, msrv)
         && SpanlessEq::new(cx).eq_expr(left_expr, struct_expr) {
         suggest(cx, parent_expr, left_expr, target_expr);
diff --git a/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs b/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs
index cc26b0f7fa8..4720a6e6888 100644
--- a/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/bind_instead_of_map.rs
@@ -41,7 +41,7 @@ pub(crate) trait BindInsteadOfMap {
     const GOOD_METHOD_NAME: &'static str;
 
     fn no_op_msg(cx: &LateContext<'_>) -> Option<String> {
-        let variant_id = cx.tcx.lang_items().require(Self::VARIANT_LANG_ITEM).ok()?;
+        let variant_id = cx.tcx.lang_items().get(Self::VARIANT_LANG_ITEM)?;
         let item_id = cx.tcx.parent(variant_id);
         Some(format!(
             "using `{}.{}({})`, which is a no-op",
@@ -52,7 +52,7 @@ pub(crate) trait BindInsteadOfMap {
     }
 
     fn lint_msg(cx: &LateContext<'_>) -> Option<String> {
-        let variant_id = cx.tcx.lang_items().require(Self::VARIANT_LANG_ITEM).ok()?;
+        let variant_id = cx.tcx.lang_items().get(Self::VARIANT_LANG_ITEM)?;
         let item_id = cx.tcx.parent(variant_id);
         Some(format!(
             "using `{}.{}(|x| {}(y))`, which is more succinctly expressed as `{}(|x| y)`",
@@ -144,7 +144,7 @@ pub(crate) trait BindInsteadOfMap {
     fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, arg: &hir::Expr<'_>) -> bool {
         if_chain! {
             if let Some(adt) = cx.typeck_results().expr_ty(recv).ty_adt_def();
-            if let Ok(vid) = cx.tcx.lang_items().require(Self::VARIANT_LANG_ITEM);
+            if let Some(vid) = cx.tcx.lang_items().get(Self::VARIANT_LANG_ITEM);
             if adt.did() == cx.tcx.parent(vid);
             then {} else { return false; }
         }
@@ -181,7 +181,7 @@ pub(crate) trait BindInsteadOfMap {
 
     fn is_variant(cx: &LateContext<'_>, res: Res) -> bool {
         if let Res::Def(DefKind::Ctor(CtorOf::Variant, CtorKind::Fn), id) = res {
-            if let Ok(variant_id) = cx.tcx.lang_items().require(Self::VARIANT_LANG_ITEM) {
+            if let Some(variant_id) = cx.tcx.lang_items().get(Self::VARIANT_LANG_ITEM) {
                 return cx.tcx.parent(id) == variant_id;
             }
         }
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_iter_cloned.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_iter_cloned.rs
index 1966a85f7a7..4eb579af7a1 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_iter_cloned.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_iter_cloned.rs
@@ -5,7 +5,7 @@ use clippy_utils::source::snippet_opt;
 use clippy_utils::ty::{get_associated_type, get_iterator_item_ty, implements_trait};
 use clippy_utils::{fn_def_id, get_parent_expr};
 use rustc_errors::Applicability;
-use rustc_hir::{def_id::DefId, Expr, ExprKind, LangItem};
+use rustc_hir::{def_id::DefId, Expr, ExprKind};
 use rustc_lint::LateContext;
 use rustc_span::{sym, Symbol};
 
@@ -100,5 +100,5 @@ pub fn check_for_loop_iter(
 
 /// Returns true if the named method is `IntoIterator::into_iter`.
 pub fn is_into_iter(cx: &LateContext<'_>, callee_def_id: DefId) -> bool {
-    cx.tcx.lang_items().require(LangItem::IntoIterIntoIter) == Ok(callee_def_id)
+    Some(callee_def_id) == cx.tcx.lang_items().into_iter_fn()
 }
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
index 3566fe9a0bb..642a64ae77b 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
@@ -7,7 +7,7 @@ use clippy_utils::visitors::find_all_ret_expressions;
 use clippy_utils::{fn_def_id, get_parent_expr, is_diag_item_method, is_diag_trait_item, return_ty};
 use clippy_utils::{meets_msrv, msrvs};
 use rustc_errors::Applicability;
-use rustc_hir::{def_id::DefId, BorrowKind, Expr, ExprKind, ItemKind, LangItem, Node};
+use rustc_hir::{def_id::DefId, BorrowKind, Expr, ExprKind, ItemKind, Node};
 use rustc_hir_typeck::{FnCtxt, Inherited};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::LateContext;
@@ -378,7 +378,7 @@ fn can_change_type<'a>(cx: &LateContext<'a>, mut expr: &'a Expr<'a>, mut ty: Ty<
             Node::Expr(parent_expr) => {
                 if let Some((callee_def_id, call_substs, recv, call_args)) = get_callee_substs_and_args(cx, parent_expr)
                 {
-                    if cx.tcx.lang_items().require(LangItem::IntoFutureIntoFuture) == Ok(callee_def_id) {
+                    if Some(callee_def_id) == cx.tcx.lang_items().into_future_fn() {
                         return false;
                     }
 
diff --git a/src/tools/clippy/clippy_lints/src/operators/assign_op_pattern.rs b/src/tools/clippy/clippy_lints/src/operators/assign_op_pattern.rs
index ee9fd94064c..9bbf385fb59 100644
--- a/src/tools/clippy/clippy_lints/src/operators/assign_op_pattern.rs
+++ b/src/tools/clippy/clippy_lints/src/operators/assign_op_pattern.rs
@@ -28,7 +28,7 @@ pub(super) fn check<'tcx>(
             let rty = cx.typeck_results().expr_ty(rhs);
             if_chain! {
                 if let Some((_, lang_item)) = binop_traits(op.node);
-                if let Ok(trait_id) = cx.tcx.lang_items().require(lang_item);
+                if let Some(trait_id) = cx.tcx.lang_items().get(lang_item);
                 let parent_fn = cx.tcx.hir().get_parent_item(e.hir_id).def_id;
                 if trait_ref_of_method(cx, parent_fn)
                     .map_or(true, |t| t.path.res.def_id() != trait_id);
diff --git a/src/tools/clippy/clippy_lints/src/suspicious_trait_impl.rs b/src/tools/clippy/clippy_lints/src/suspicious_trait_impl.rs
index b57b484bdc8..6271ea02731 100644
--- a/src/tools/clippy/clippy_lints/src/suspicious_trait_impl.rs
+++ b/src/tools/clippy/clippy_lints/src/suspicious_trait_impl.rs
@@ -60,8 +60,8 @@ impl<'tcx> LateLintPass<'tcx> for SuspiciousImpl {
         if_chain! {
             if let hir::ExprKind::Binary(binop, _, _) | hir::ExprKind::AssignOp(binop, ..) = expr.kind;
             if let Some((binop_trait_lang, op_assign_trait_lang)) = binop_traits(binop.node);
-            if let Ok(binop_trait_id) = cx.tcx.lang_items().require(binop_trait_lang);
-            if let Ok(op_assign_trait_id) = cx.tcx.lang_items().require(op_assign_trait_lang);
+            if let Some(binop_trait_id) = cx.tcx.lang_items().get(binop_trait_lang);
+            if let Some(op_assign_trait_id) = cx.tcx.lang_items().get(op_assign_trait_lang);
 
             // Check for more than one binary operation in the implemented function
             // Linting when multiple operations are involved can result in false positives
@@ -78,7 +78,7 @@ impl<'tcx> LateLintPass<'tcx> for SuspiciousImpl {
                 (&OP_ASSIGN_TRAITS, SUSPICIOUS_OP_ASSIGN_IMPL),
             ]
                 .iter()
-                .find(|&(ts, _)| ts.iter().any(|&t| Ok(trait_id) == cx.tcx.lang_items().require(t)));
+                .find(|&(ts, _)| ts.iter().any(|&t| Some(trait_id) == cx.tcx.lang_items().get(t)));
             if count_binops(body.value) == 1;
             then {
                 span_lint(
diff --git a/src/tools/clippy/clippy_lints/src/unnecessary_owned_empty_strings.rs b/src/tools/clippy/clippy_lints/src/unnecessary_owned_empty_strings.rs
index 016aacbf9da..ab73f0fc44f 100644
--- a/src/tools/clippy/clippy_lints/src/unnecessary_owned_empty_strings.rs
+++ b/src/tools/clippy/clippy_lints/src/unnecessary_owned_empty_strings.rs
@@ -3,7 +3,7 @@ use clippy_utils::{match_def_path, paths};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
-use rustc_hir::{BorrowKind, Expr, ExprKind, LangItem, Mutability};
+use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -55,7 +55,7 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryOwnedEmptyStrings {
                         );
                 } else {
                     if_chain! {
-                        if cx.tcx.lang_items().require(LangItem::FromFrom).ok() == Some(fun_def_id);
+                        if Some(fun_def_id) == cx.tcx.lang_items().from_fn();
                         if let [.., last_arg] = args;
                         if let ExprKind::Lit(spanned) = &last_arg.kind;
                         if let LitKind::Str(symbol, _) = spanned.node;
diff --git a/src/tools/clippy/clippy_lints/src/unused_peekable.rs b/src/tools/clippy/clippy_lints/src/unused_peekable.rs
index f1cebf0f992..b452be08409 100644
--- a/src/tools/clippy/clippy_lints/src/unused_peekable.rs
+++ b/src/tools/clippy/clippy_lints/src/unused_peekable.rs
@@ -3,7 +3,6 @@ use clippy_utils::ty::{match_type, peel_mid_ty_refs_is_mutable};
 use clippy_utils::{fn_def_id, is_trait_method, path_to_local_id, paths, peel_ref_operators};
 use rustc_ast::Mutability;
 use rustc_hir::intravisit::{walk_expr, Visitor};
-use rustc_hir::lang_items::LangItem;
 use rustc_hir::{Block, Expr, ExprKind, HirId, Local, Node, PatKind, PathSegment, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter::OnlyBodies;
@@ -132,11 +131,11 @@ impl<'tcx> Visitor<'tcx> for PeekableVisitor<'_, 'tcx> {
                             // If the Peekable is passed to a function, stop
                             ExprKind::Call(_, args) => {
                                 if let Some(func_did) = fn_def_id(self.cx, expr)
-                                    && let Ok(into_iter_did) = self
+                                    && let Some(into_iter_did) = self
                                         .cx
                                         .tcx
                                         .lang_items()
-                                        .require(LangItem::IntoIterIntoIter)
+                                        .into_iter_fn()
                                     && func_did == into_iter_did
                                 {
                                     // Probably a for loop desugar, stop searching
diff --git a/src/tools/clippy/clippy_lints/src/useless_conversion.rs b/src/tools/clippy/clippy_lints/src/useless_conversion.rs
index 1f69db1cbca..3743d5d97a7 100644
--- a/src/tools/clippy/clippy_lints/src/useless_conversion.rs
+++ b/src/tools/clippy/clippy_lints/src/useless_conversion.rs
@@ -5,7 +5,7 @@ use clippy_utils::ty::{is_type_diagnostic_item, same_type_and_consts};
 use clippy_utils::{get_parent_expr, is_trait_method, match_def_path, paths};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind, HirId, LangItem, MatchSource};
+use rustc_hir::{Expr, ExprKind, HirId, MatchSource};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
@@ -153,7 +153,7 @@ impl<'tcx> LateLintPass<'tcx> for UselessConversion {
                         }
 
                         if_chain! {
-                            if cx.tcx.lang_items().require(LangItem::FromFrom).ok() == Some(def_id);
+                            if Some(def_id) == cx.tcx.lang_items().from_fn();
                             if same_type_and_consts(a, b);
 
                             then {
diff --git a/src/tools/clippy/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs b/src/tools/clippy/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs
index 4cf76f53625..2a028c8141f 100644
--- a/src/tools/clippy/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs
@@ -152,7 +152,7 @@ impl UnnecessaryDefPath {
                         has_ctor,
                     ),
                     (0, Item::LangItem(item)) => (
-                        format!("{cx_snip}.tcx.lang_items().require(LangItem::{item}).ok() == Some({def_snip})"),
+                        format!("{cx_snip}.tcx.lang_items().get(LangItem::{item}) == Some({def_snip})"),
                         has_ctor,
                     ),
                     // match_trait_method
@@ -184,7 +184,7 @@ impl UnnecessaryDefPath {
                     (3, Item::LangItem(item)) => (
                         format!(
                             "path_res({cx_snip}, {def_snip}).opt_def_id()\
-                                .map_or(false, |id| {cx_snip}.tcx.lang_items().require(LangItem::{item}).ok() == Some(id))",
+                                .map_or(false, |id| {cx_snip}.tcx.lang_items().get(LangItem::{item}) == Some(id))",
                         ),
                         false,
                     ),
diff --git a/src/tools/clippy/clippy_utils/src/lib.rs b/src/tools/clippy/clippy_utils/src/lib.rs
index 3ebfc5e00e1..d32cf1a7936 100644
--- a/src/tools/clippy/clippy_utils/src/lib.rs
+++ b/src/tools/clippy/clippy_utils/src/lib.rs
@@ -247,7 +247,7 @@ pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
 /// For example, use this to check whether a function call or a pattern is `Some(..)`.
 pub fn is_res_lang_ctor(cx: &LateContext<'_>, res: Res, lang_item: LangItem) -> bool {
     if let Res::Def(DefKind::Ctor(..), id) = res
-        && let Ok(lang_id) = cx.tcx.lang_items().require(lang_item)
+        && let Some(lang_id) = cx.tcx.lang_items().get(lang_item)
         && let Some(id) = cx.tcx.opt_parent(id)
     {
         id == lang_id
@@ -303,7 +303,7 @@ pub fn is_lang_item_or_ctor(cx: &LateContext<'_>, did: DefId, item: LangItem) ->
         _ => did,
     };
 
-    cx.tcx.lang_items().require(item).map_or(false, |id| id == did)
+    cx.tcx.lang_items().get(item) == Some(did)
 }
 
 pub fn is_unit_expr(expr: &Expr<'_>) -> bool {
diff --git a/src/tools/clippy/clippy_utils/src/ty.rs b/src/tools/clippy/clippy_utils/src/ty.rs
index 4e024ce4017..3a144c2bb22 100644
--- a/src/tools/clippy/clippy_utils/src/ty.rs
+++ b/src/tools/clippy/clippy_utils/src/ty.rs
@@ -318,11 +318,7 @@ pub fn is_type_diagnostic_item(cx: &LateContext<'_>, ty: Ty<'_>, diag_item: Symb
 /// Returns `false` if the `LangItem` is not defined.
 pub fn is_type_lang_item(cx: &LateContext<'_>, ty: Ty<'_>, lang_item: hir::LangItem) -> bool {
     match ty.kind() {
-        ty::Adt(adt, _) => cx
-            .tcx
-            .lang_items()
-            .require(lang_item)
-            .map_or(false, |li| li == adt.did()),
+        ty::Adt(adt, _) => cx.tcx.lang_items().get(lang_item) == Some(adt.did()),
         _ => false,
     }
 }