Merge commit '4911ab124c481430672a3833b37075e6435ec34d' into clippyup

[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 9ee875d7516eba3d29e70f4a372f8797f3ed85ce..bff53eb8ccada92e7cc8580e2f545a617a9cf2f9 100644 (file)
--- a/clippy_lints/src/needless_borrow.rs
+++ b/clippy_lints/src/needless_borrow.rs
@@ -10,6 +10,7 @@
 use rustc_middle::ty;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for address of operations (`&`) that are going to
@@ -18,12 +19,16 @@
     /// **Why is this bad?** Suggests that the receiver of the expression borrows
     /// the expression.
     ///
+    /// **Known problems:** None.
+    ///
     /// **Example:**
     /// ```rust
+    /// // Bad
     /// let x: &i32 = &&&&&&5;
-    /// ```
     ///
-    /// **Known problems:** None.
+    /// // Good
+    /// let x: &i32 = &5;
+    /// ```
     pub NEEDLESS_BORROW,
     nursery,
     "taking a reference that is going to be automatically dereferenced"
@@ -36,14 +41,14 @@ pub struct NeedlessBorrow {
 
 impl_lint_pass!(NeedlessBorrow => [NEEDLESS_BORROW]);
 
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessBorrow {
-    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) {
+impl<'tcx> LateLintPass<'tcx> for NeedlessBorrow {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
         if e.span.from_expansion() || self.derived_item.is_some() {
             return;
         }
         if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, ref inner) = e.kind {
-            if let ty::Ref(..) = cx.tables.expr_ty(inner).kind {
-                for adj3 in cx.tables.expr_adjustments(e).windows(3) {
+            if let ty::Ref(_, ty, _) = cx.typeck_results().expr_ty(inner).kind() {
+                for adj3 in cx.typeck_results().expr_adjustments(e).windows(3) {
                     if let [Adjustment {
                         kind: Adjust::Deref(_), ..
                     }, Adjustment {
@@ -57,8 +62,11 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) {
                             cx,
                             NEEDLESS_BORROW,
                             e.span,
-                            "this expression borrows a reference that is immediately dereferenced \
+                            &format!(
+                                "this expression borrows a reference (`&{}`) that is immediately dereferenced \
                              by the compiler",
+                                ty
+                            ),
                             |diag| {
                                 if let Some(snippet) = snippet_opt(cx, inner.span) {
                                     diag.span_suggestion(
@@ -75,15 +83,15 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) {
             }
         }
     }
-    fn check_pat(&mut self, cx: &LateContext<'a, 'tcx>, pat: &'tcx Pat<'_>) {
+    fn check_pat(&mut self, cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>) {
         if pat.span.from_expansion() || self.derived_item.is_some() {
             return;
         }
         if_chain! {
             if let PatKind::Binding(BindingAnnotation::Ref, .., name, _) = pat.kind;
-            if let ty::Ref(_, tam, mutbl) = cx.tables.pat_ty(pat).kind;
+            if let ty::Ref(_, tam, mutbl) = *cx.typeck_results().pat_ty(pat).kind();
             if mutbl == Mutability::Not;
-            if let ty::Ref(_, _, mutbl) = tam.kind;
+            if let ty::Ref(_, _, mutbl) = *tam.kind();
             // only lint immutable refs, because borrowed `&mut T` cannot be moved out
             if mutbl == Mutability::Not;
             then {
@@ -107,14 +115,14 @@ fn check_pat(&mut self, cx: &LateContext<'a, 'tcx>, pat: &'tcx Pat<'_>) {
         }
     }
 
-    fn check_item(&mut self, _: &LateContext<'a, 'tcx>, item: &'tcx Item<'_>) {
-        if item.attrs.iter().any(|a| a.check_name(sym!(automatically_derived))) {
+    fn check_item(&mut self, _: &LateContext<'tcx>, item: &'tcx Item<'_>) {
+        if item.attrs.iter().any(|a| a.has_name(sym::automatically_derived)) {
             debug_assert!(self.derived_item.is_none());
             self.derived_item = Some(item.hir_id);
         }
     }
 
-    fn check_item_post(&mut self, _: &LateContext<'a, 'tcx>, item: &'tcx Item<'_>) {
+    fn check_item_post(&mut self, _: &LateContext<'tcx>, item: &'tcx Item<'_>) {
         if let Some(id) = self.derived_item {
             if item.hir_id == id {
                 self.derived_item = None;