Suppress must_use in compiler and tools

Author: compiler-errors

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -2174,7 +2174,7 @@ fn add_library_search_dirs(
         return;
     }
 
-    walk_native_lib_search_dirs(
+    let _ = walk_native_lib_search_dirs(
         sess,
         self_contained_components,
         apple_sdk_root,

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -519,7 +519,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         }
                     }
                     _ => {
-                        intravisit::walk_pat(self, p);
+                        let _ = intravisit::walk_pat(self, p);
                     }
                 }
                 ControlFlow::Continue(())
@@ -542,7 +542,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     method_name,
                     sugg_let: None,
                 };
-                let_visitor.visit_body(&body);
+                let _ = let_visitor.visit_body(&body);
                 if let Some(sugg_let) = let_visitor.sugg_let
                     && let Some(self_ty) = self.node_ty_opt(sugg_let.init_hir_id)
                 {

compiler/rustc_privacy/src/lib.rs

@@ -1356,12 +1356,12 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
                 GenericParamDefKind::Lifetime => {}
                 GenericParamDefKind::Type { has_default, .. } => {
                     if has_default {
-                        self.visit(self.tcx.type_of(param.def_id).instantiate_identity());
+                        let _ = self.visit(self.tcx.type_of(param.def_id).instantiate_identity());
                     }
                 }
                 // FIXME(generic_const_exprs): May want to look inside const here
                 GenericParamDefKind::Const { .. } => {
-                    self.visit(self.tcx.type_of(param.def_id).instantiate_identity());
+                    let _ = self.visit(self.tcx.type_of(param.def_id).instantiate_identity());
                 }
             }
         }
@@ -1376,19 +1376,19 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
         // consider the ones that the user wrote. This is important
         // for the inferred outlives rules; see
         // `tests/ui/rfc-2093-infer-outlives/privacy.rs`.
-        self.visit_predicates(self.tcx.explicit_predicates_of(self.item_def_id));
+        let _ = self.visit_predicates(self.tcx.explicit_predicates_of(self.item_def_id));
         self
     }
 
     fn bounds(&mut self) -> &mut Self {
         self.in_primary_interface = false;
-        self.visit_clauses(self.tcx.explicit_item_bounds(self.item_def_id).skip_binder());
+        let _ = self.visit_clauses(self.tcx.explicit_item_bounds(self.item_def_id).skip_binder());
         self
     }
 
     fn ty(&mut self) -> &mut Self {
         self.in_primary_interface = true;
-        self.visit(self.tcx.type_of(self.item_def_id).instantiate_identity());
+        let _ = self.visit(self.tcx.type_of(self.item_def_id).instantiate_identity());
         self
     }
 
@@ -1780,7 +1780,7 @@ fn check_mod_privacy(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
 
     let module = tcx.hir_module_items(module_def_id);
     for def_id in module.definitions() {
-        rustc_ty_utils::sig_types::walk_types(tcx, def_id, &mut visitor);
+        let _ = rustc_ty_utils::sig_types::walk_types(tcx, def_id, &mut visitor);
 
         if let Some(body_id) = tcx.hir_maybe_body_owned_by(def_id) {
             visitor.visit_nested_body(body_id.id());
@@ -1793,7 +1793,11 @@ fn check_mod_privacy(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
                 let trait_ref = tcx.impl_trait_ref(id.owner_id.def_id).unwrap();
                 let trait_ref = trait_ref.instantiate_identity();
                 visitor.span = item.path.span;
-                visitor.visit_def_id(trait_ref.def_id, "trait", &trait_ref.print_only_trait_path());
+                let _ = visitor.visit_def_id(
+                    trait_ref.def_id,
+                    "trait",
+                    &trait_ref.print_only_trait_path(),
+                );
             }
         }
     }

compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/find_anon_type.rs

@@ -77,15 +77,15 @@ impl<'tcx> Visitor<'tcx> for FindNestedTypeVisitor<'tcx> {
         match arg.kind {
             hir::TyKind::BareFn(_) => {
                 self.current_index.shift_in(1);
-                intravisit::walk_ty(self, arg);
+                let _ = intravisit::walk_ty(self, arg);
                 self.current_index.shift_out(1);
                 return ControlFlow::Continue(());
             }
 
             hir::TyKind::TraitObject(bounds, ..) => {
                 for bound in bounds {
                     self.current_index.shift_in(1);
-                    self.visit_poly_trait_ref(bound);
+                    let _ = self.visit_poly_trait_ref(bound);
                     self.current_index.shift_out(1);
                 }
             }

compiler/rustc_trait_selection/src/traits/project.rs

@@ -743,7 +743,7 @@ fn assemble_candidates_from_trait_def<'cx, 'tcx>(
 ) {
     debug!("assemble_candidates_from_trait_def(..)");
     let mut ambiguous = false;
-    selcx.for_each_item_bound(
+    let _ = selcx.for_each_item_bound(
         obligation.predicate.self_ty(),
         |selcx, clause, _| {
             let Some(clause) = clause.as_projection_clause() else {

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -176,7 +176,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             // normalization, so try to deduplicate when possible to avoid
             // unnecessary ambiguity.
             let mut distinct_normalized_bounds = FxHashSet::default();
-            self.for_each_item_bound::<!>(
+            let _ = self.for_each_item_bound::<!>(
                 placeholder_trait_predicate.self_ty(),
                 |selcx, bound, idx| {
                     let Some(bound) = bound.as_trait_clause() else {

compiler/rustc_type_ir/src/binder.rs

@@ -112,7 +112,7 @@ where
     pub fn bind_with_vars(value: T, bound_vars: I::BoundVarKinds) -> Binder<I, T> {
         if cfg!(debug_assertions) {
             let mut validator = ValidateBoundVars::new(bound_vars);
-            value.visit_with(&mut validator);
+            let _ = value.visit_with(&mut validator);
         }
         Binder { value, bound_vars }
     }
@@ -196,7 +196,7 @@ impl<I: Interner, T> Binder<I, T> {
         let value = f(value);
         if cfg!(debug_assertions) {
             let mut validator = ValidateBoundVars::new(bound_vars);
-            value.visit_with(&mut validator);
+            let _ = value.visit_with(&mut validator);
         }
         Binder { value, bound_vars }
     }
@@ -209,7 +209,7 @@ impl<I: Interner, T> Binder<I, T> {
         let value = f(value)?;
         if cfg!(debug_assertions) {
             let mut validator = ValidateBoundVars::new(bound_vars);
-            value.visit_with(&mut validator);
+            let _ = value.visit_with(&mut validator);
         }
         Ok(Binder { value, bound_vars })
     }

src/librustdoc/html/markdown.rs

@@ -1569,7 +1569,7 @@ fn markdown_summary_with_limit(
 
     let mut buf = HtmlWithLimit::new(length_limit);
     let mut stopped_early = false;
-    p.try_for_each(|event| {
+    let _ = p.try_for_each(|event| {
         match &event {
             Event::Text(text) => {
                 let r =

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

@@ -127,7 +127,7 @@ impl BreakAfterExprVisitor {
         };
 
         get_enclosing_block(cx, hir_id).is_some_and(|block| {
-            visitor.visit_block(block);
+            let _ = visitor.visit_block(block);
             visitor.break_after_expr
         })
     }

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

@@ -41,7 +41,7 @@ pub fn check(cx: &LateContext<'_>, call: &Expr<'_>, recv: &Expr<'_>, arg: &Expr<
         // We've checked that `call` is a call to `Stdin::read_line()` with the right receiver,
         // now let's check if the first use of the string passed to `::read_line()`
         // is used for operations that will always fail (e.g. parsing "6\n" into a number)
-        for_each_local_use_after_expr(cx, local_id, call.hir_id, |expr| {
+        let _ = for_each_local_use_after_expr(cx, local_id, call.hir_id, |expr| {
             if let Some(parent) = get_parent_expr(cx, expr) {
                 let data = if let ExprKind::MethodCall(segment, recv, args, span) = parent.kind {
                     if args.is_empty()