modify code

[rust.git] / clippy_lints / src / mut_reference.rs

diff --git a/clippy_lints/src/mut_reference.rs b/clippy_lints/src/mut_reference.rs
index b8dc5081632972827f9fc9203246dabc8649d096..5c3e505c06c47821976f3377b1606a4d71c5d83e 100644 (file)
--- a/clippy_lints/src/mut_reference.rs
+++ b/clippy_lints/src/mut_reference.rs
@@ -1,20 +1,21 @@
-use crate::utils::span_lint;
+use clippy_utils::diagnostics::span_lint;
 use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{self, Ty};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use std::iter;
 
 declare_clippy_lint! {
-    /// **What it does:** Detects passing a mutable reference to a function that only
+    /// ### What it does
+    /// Detects passing a mutable reference to a function that only
     /// requires an immutable reference.
     ///
-    /// **Why is this bad?** The immutable reference rules out all other references
-    /// to the value. Also the code misleads about the intent of the call site.
+    /// ### Why is this bad?
+    /// The mutable reference rules out all other references to
+    /// the value. Also the code misleads about the intent of the call site.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// // Bad
     /// my_vec.push(&mut value)
@@ -22,6 +23,7 @@
     /// // Good
     /// my_vec.push(&value)
     /// ```
+    #[clippy::version = "pre 1.29.0"]
     pub UNNECESSARY_MUT_PASSED,
     style,
     "an argument passed as a mutable reference although the callee only demands an immutable reference"
@@ -32,33 +34,40 @@
 impl<'tcx> LateLintPass<'tcx> for UnnecessaryMutPassed {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
         match e.kind {
-            ExprKind::Call(ref fn_expr, ref arguments) => {
+            ExprKind::Call(fn_expr, arguments) => {
                 if let ExprKind::Path(ref path) = fn_expr.kind {
                     check_arguments(
                         cx,
                         arguments,
                         cx.typeck_results().expr_ty(fn_expr),
                         &rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_qpath(path, false)),
+                        "function",
                     );
                 }
             },
-            ExprKind::MethodCall(ref path, _, ref arguments, _) => {
+            ExprKind::MethodCall(path, arguments, _) => {
                 let def_id = cx.typeck_results().type_dependent_def_id(e.hir_id).unwrap();
                 let substs = cx.typeck_results().node_substs(e.hir_id);
                 let method_type = cx.tcx.type_of(def_id).subst(cx.tcx, substs);
-                check_arguments(cx, arguments, method_type, &path.ident.as_str())
+                check_arguments(cx, arguments, method_type, path.ident.as_str(), "method");
             },
             _ => (),
         }
     }
 }
 
-fn check_arguments<'tcx>(cx: &LateContext<'tcx>, arguments: &[Expr<'_>], type_definition: Ty<'tcx>, name: &str) {
-    match type_definition.kind {
+fn check_arguments<'tcx>(
+    cx: &LateContext<'tcx>,
+    arguments: &[Expr<'_>],
+    type_definition: Ty<'tcx>,
+    name: &str,
+    fn_kind: &str,
+) {
+    match type_definition.kind() {
         ty::FnDef(..) | ty::FnPtr(_) => {
             let parameters = type_definition.fn_sig(cx.tcx).skip_binder().inputs();
-            for (argument, parameter) in arguments.iter().zip(parameters.iter()) {
-                match parameter.kind {
+            for (argument, parameter) in iter::zip(arguments, parameters) {
+                match parameter.kind() {
                     ty::Ref(_, _, Mutability::Not)
                     | ty::RawPtr(ty::TypeAndMut {
                         mutbl: Mutability::Not, ..
@@ -68,7 +77,7 @@ fn check_arguments<'tcx>(cx: &LateContext<'tcx>, arguments: &[Expr<'_>], type_de
                                 cx,
                                 UNNECESSARY_MUT_PASSED,
                                 argument.span,
-                                &format!("The function/method `{}` doesn't need a mutable reference", name),
+                                &format!("the {} `{}` doesn't need a mutable reference", fn_kind, name),
                             );
                         }
                     },