use BindingAnnotation instead of BindingMode

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

diff --git a/clippy_lints/src/needless_borrow.rs b/clippy_lints/src/needless_borrow.rs
index ab87201d230fc9e42fc783ae46d69723f04cd78e..385fcc86adb6a50f8fce8fe28cb89946c8da4737 100644 (file)
--- a/clippy_lints/src/needless_borrow.rs
+++ b/clippy_lints/src/needless_borrow.rs
@@ -3,17 +3,18 @@
 //! This lint is **warn** by default
 
 use rustc::lint::*;
-use rustc::hir::{ExprAddrOf, Expr, MutImmutable, Pat, PatKind, BindingMode};
-use rustc::ty::TyRef;
+use rustc::hir::{ExprAddrOf, Expr, MutImmutable, Pat, PatKind, BindingAnnotation};
+use rustc::ty;
+use rustc::ty::adjustment::{Adjustment, Adjust};
 use utils::{span_lint, in_macro};
-use rustc::ty::adjustment::AutoAdjustment::AdjustDerefRef;
 
-/// **What it does:** This lint checks for address of operations (`&`) that are going to be
-/// dereferenced immediately by the compiler
+/// **What it does:** Checks for address of operations (`&`) that are going to
+/// be dereferenced immediately by the compiler.
 ///
-/// **Why is this bad?** Suggests that the receiver of the expression borrows the expression.
+/// **Why is this bad?** Suggests that the receiver of the expression borrows
+/// the expression.
 ///
-/// **Known problems:**
+/// **Known problems:** None.
 ///
 /// **Example:**
 /// ```rust
@@ -34,15 +35,19 @@ fn get_lints(&self) -> LintArray {
     }
 }
 
-impl LateLintPass for NeedlessBorrow {
-    fn check_expr(&mut self, cx: &LateContext, e: &Expr) {
-        if in_macro(cx, e.span) {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessBorrow {
+    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
+        if in_macro(e.span) {
             return;
         }
         if let ExprAddrOf(MutImmutable, ref inner) = e.node {
-            if let TyRef(..) = cx.tcx.expr_ty(inner).sty {
-                if let Some(&AdjustDerefRef(ref deref)) = cx.tcx.tables.borrow().adjustments.get(&e.id) {
-                    if deref.autoderefs > 1 && deref.autoref.is_some() {
+            if let ty::TyRef(..) = cx.tables.expr_ty(inner).sty {
+                for adj3 in cx.tables.expr_adjustments(e).windows(3) {
+                    if let [
+                        Adjustment { kind: Adjust::Deref(_), .. },
+                        Adjustment { kind: Adjust::Deref(_), .. },
+                        Adjustment { kind: Adjust::Borrow(_), .. }
+                    ] = *adj3 {
                         span_lint(cx,
                                   NEEDLESS_BORROW,
                                   e.span,
@@ -53,21 +58,19 @@ fn check_expr(&mut self, cx: &LateContext, e: &Expr) {
             }
         }
     }
-    fn check_pat(&mut self, cx: &LateContext, pat: &Pat) {
-        if in_macro(cx, pat.span) {
+    fn check_pat(&mut self, cx: &LateContext<'a, 'tcx>, pat: &'tcx Pat) {
+        if in_macro(pat.span) {
             return;
         }
-        if let PatKind::Binding(BindingMode::BindByRef(MutImmutable), _, _) = pat.node {
-            if let TyRef(_, ref tam) = cx.tcx.pat_ty(pat).sty {
-                if tam.mutbl == MutImmutable {
-                    if let TyRef(..) = tam.ty.sty {
-                        span_lint(cx,
-                                  NEEDLESS_BORROW,
-                                  pat.span,
-                                  "this pattern creates a reference to a reference")
-                    }
-                }
-            }
-        }
+        if_let_chain! {[
+            let PatKind::Binding(BindingAnnotation::Ref, _, _, _) = pat.node,
+            let ty::TyRef(_, ref tam) = cx.tables.pat_ty(pat).sty,
+            tam.mutbl == MutImmutable,
+            let ty::TyRef(_, ref tam) = tam.ty.sty,
+            // only lint immutable refs, because borrowed `&mut T` cannot be moved out
+            tam.mutbl == MutImmutable,
+        ], {
+            span_lint(cx, NEEDLESS_BORROW, pat.span, "this pattern creates a reference to a reference")
+        }}
     }
 }