X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fneedless_borrow.rs;h=1aadcfd87b60f73a1dc44626adc30300cae35d93;hb=dc9560cfd2e466ffbaf4615197ed4386ccb90c1d;hp=c2b1b896cf4dbcae7e273316de9a07f337126eae;hpb=353668ee6c5b07dd865f6855ad83f0c2aa234dc7;p=rust.git

diff --git a/clippy_lints/src/needless_borrow.rs b/clippy_lints/src/needless_borrow.rs
index c2b1b896cf4..1aadcfd87b6 100644
--- a/clippy_lints/src/needless_borrow.rs
+++ b/clippy_lints/src/needless_borrow.rs
@@ -2,14 +2,15 @@
 //!
 //! This lint is **warn** by default
 
-use crate::utils::{snippet_opt, span_lint_and_then};
+use crate::utils::{is_automatically_derived, snippet_opt, span_lint_and_then};
 use if_chain::if_chain;
-use rustc::hir::{BindingAnnotation, Expr, ExprKind, HirId, Item, Mutability, Pat, PatKind};
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::ty;
-use rustc::ty::adjustment::{Adjust, Adjustment};
-use rustc::{declare_tool_lint, impl_lint_pass};
 use rustc_errors::Applicability;
+use rustc_hir::{BindingAnnotation, BorrowKind, Expr, ExprKind, Item, Mutability, Pat, PatKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty;
+use rustc_middle::ty::adjustment::{Adjust, Adjustment};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::def_id::LocalDefId;
 
 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"
@@ -31,19 +36,19 @@
 
 #[derive(Default)]
 pub struct NeedlessBorrow {
-    derived_item: Option<HirId>,
+    derived_item: Option<LocalDefId>,
 }
 
 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(Mutability::Immutable, 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 ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, ref inner) = e.kind {
+            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 {
@@ -57,11 +62,14 @@ 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",
-                            |db| {
+                                ty
+                            ),
+                            |diag| {
                                 if let Some(snippet) = snippet_opt(cx, inner.span) {
-                                    db.span_suggestion(
+                                    diag.span_suggestion(
                                         e.span,
                                         "change this to",
                                         snippet,
@@ -75,26 +83,26 @@ 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 mutbl == Mutability::Immutable;
-            if let ty::Ref(_, _, mutbl) = tam.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();
             // only lint immutable refs, because borrowed `&mut T` cannot be moved out
-            if mutbl == Mutability::Immutable;
+            if mutbl == Mutability::Not;
             then {
                 span_lint_and_then(
                     cx,
                     NEEDLESS_BORROW,
                     pat.span,
                     "this pattern creates a reference to a reference",
-                    |db| {
+                    |diag| {
                         if let Some(snippet) = snippet_opt(cx, name.span) {
-                            db.span_suggestion(
+                            diag.span_suggestion(
                                 pat.span,
                                 "change this to",
                                 snippet,
@@ -107,16 +115,17 @@ 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, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
+        let attrs = cx.tcx.hir().attrs(item.hir_id());
+        if is_automatically_derived(attrs) {
             debug_assert!(self.derived_item.is_none());
-            self.derived_item = Some(item.hir_id);
+            self.derived_item = Some(item.def_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 {
+            if item.def_id == id {
                 self.derived_item = None;
             }
         }