Merge commit 'ac0e10aa68325235069a842f47499852b2dee79e' into clippyup

[rust.git] / src / tools / clippy / clippy_lints / src / functions / must_use.rs

diff --git a/src/tools/clippy/clippy_lints/src/functions/must_use.rs b/src/tools/clippy/clippy_lints/src/functions/must_use.rs
index d6d33bda173817713ce8941edd67d25813c619a7..d263804f32cf48538be82cad8e979d6543d490f8 100644 (file)
--- a/src/tools/clippy/clippy_lints/src/functions/must_use.rs
+++ b/src/tools/clippy/clippy_lints/src/functions/must_use.rs
@@ -1,7 +1,7 @@
 use rustc_ast::ast::Attribute;
 use rustc_errors::Applicability;
 use rustc_hir::def_id::{DefIdSet, LocalDefId};
-use rustc_hir::{self as hir, def::Res, intravisit, QPath};
+use rustc_hir::{self as hir, def::Res, QPath};
 use rustc_lint::{LateContext, LintContext};
 use rustc_middle::{
     lint::in_external_macro,
@@ -13,8 +13,11 @@
 use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_then};
 use clippy_utils::source::snippet_opt;
 use clippy_utils::ty::is_must_use_ty;
+use clippy_utils::visitors::for_each_expr;
 use clippy_utils::{match_def_path, return_ty, trait_ref_of_method};
 
+use core::ops::ControlFlow;
+
 use super::{DOUBLE_MUST_USE, MUST_USE_CANDIDATE, MUST_USE_UNIT};
 
 pub(super) fn check_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
@@ -47,7 +50,8 @@ pub(super) fn check_impl_item<'tcx>(cx: &LateContext<'tcx>, item: &'tcx hir::Imp
         let attr = cx.tcx.get_attr(item.def_id.to_def_id(), sym::must_use);
         if let Some(attr) = attr {
             check_needless_must_use(cx, sig.decl, item.hir_id(), item.span, fn_header_span, attr);
-        } else if is_public && !is_proc_macro(cx.sess(), attrs) && trait_ref_of_method(cx, item.def_id.def_id).is_none() {
+        } else if is_public && !is_proc_macro(cx.sess(), attrs) && trait_ref_of_method(cx, item.def_id.def_id).is_none()
+        {
             check_must_use_candidate(
                 cx,
                 sig.decl,
@@ -143,7 +147,7 @@ fn check_must_use_candidate<'tcx>(
             diag.span_suggestion(
                 fn_span,
                 "add the attribute",
-                format!("#[must_use] {}", snippet),
+                format!("#[must_use] {snippet}"),
                 Applicability::MachineApplicable,
             );
         }
@@ -199,79 +203,65 @@ fn is_mutable_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, span: Span, tys: &m
     }
 }
 
-struct StaticMutVisitor<'a, 'tcx> {
-    cx: &'a LateContext<'tcx>,
-    mutates_static: bool,
+fn is_mutated_static(e: &hir::Expr<'_>) -> bool {
+    use hir::ExprKind::{Field, Index, Path};
+
+    match e.kind {
+        Path(QPath::Resolved(_, path)) => !matches!(path.res, Res::Local(_)),
+        Path(_) => true,
+        Field(inner, _) | Index(inner, _) => is_mutated_static(inner),
+        _ => false,
+    }
 }
 
-impl<'a, 'tcx> intravisit::Visitor<'tcx> for StaticMutVisitor<'a, 'tcx> {
-    fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
+fn mutates_static<'tcx>(cx: &LateContext<'tcx>, body: &'tcx hir::Body<'_>) -> bool {
+    for_each_expr(body.value, |e| {
         use hir::ExprKind::{AddrOf, Assign, AssignOp, Call, MethodCall};
 
-        if self.mutates_static {
-            return;
-        }
-        match expr.kind {
+        match e.kind {
             Call(_, args) => {
                 let mut tys = DefIdSet::default();
                 for arg in args {
-                    if self.cx.tcx.has_typeck_results(arg.hir_id.owner.to_def_id())
+                    if cx.tcx.has_typeck_results(arg.hir_id.owner.to_def_id())
                         && is_mutable_ty(
-                            self.cx,
-                            self.cx.tcx.typeck(arg.hir_id.owner.def_id).expr_ty(arg),
+                            cx,
+                            cx.tcx.typeck(arg.hir_id.owner.def_id).expr_ty(arg),
                             arg.span,
                             &mut tys,
                         )
                         && is_mutated_static(arg)
                     {
-                        self.mutates_static = true;
-                        return;
+                        return ControlFlow::Break(());
                     }
                     tys.clear();
                 }
+                ControlFlow::Continue(())
             },
             MethodCall(_, receiver, args, _) => {
                 let mut tys = DefIdSet::default();
                 for arg in std::iter::once(receiver).chain(args.iter()) {
-                    if self.cx.tcx.has_typeck_results(arg.hir_id.owner.to_def_id())
+                    if cx.tcx.has_typeck_results(arg.hir_id.owner.to_def_id())
                         && is_mutable_ty(
-                            self.cx,
-                            self.cx.tcx.typeck(arg.hir_id.owner.def_id).expr_ty(arg),
+                            cx,
+                            cx.tcx.typeck(arg.hir_id.owner.def_id).expr_ty(arg),
                             arg.span,
                             &mut tys,
                         )
                         && is_mutated_static(arg)
                     {
-                        self.mutates_static = true;
-                        return;
+                        return ControlFlow::Break(());
                     }
                     tys.clear();
                 }
+                ControlFlow::Continue(())
             },
-            Assign(target, ..) | AssignOp(_, target, _) | AddrOf(_, hir::Mutability::Mut, target) => {
-                self.mutates_static |= is_mutated_static(target);
+            Assign(target, ..) | AssignOp(_, target, _) | AddrOf(_, hir::Mutability::Mut, target)
+                if is_mutated_static(target) =>
+            {
+                ControlFlow::Break(())
             },
-            _ => {},
+            _ => ControlFlow::Continue(()),
         }
-    }
-}
-
-fn is_mutated_static(e: &hir::Expr<'_>) -> bool {
-    use hir::ExprKind::{Field, Index, Path};
-
-    match e.kind {
-        Path(QPath::Resolved(_, path)) => !matches!(path.res, Res::Local(_)),
-        Path(_) => true,
-        Field(inner, _) | Index(inner, _) => is_mutated_static(inner),
-        _ => false,
-    }
-}
-
-fn mutates_static<'tcx>(cx: &LateContext<'tcx>, body: &'tcx hir::Body<'_>) -> bool {
-    let mut v = StaticMutVisitor {
-        cx,
-        mutates_static: false,
-    };
-    intravisit::walk_expr(&mut v, body.value);
-    v.mutates_static
+    })
+    .is_some()
 }