X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fneedless_borrow.rs;h=1bea93fcb75220ba364c05b91bc70a0b369cd9d2;hb=6e03a306ac44c6670064c68197df8813fe1cac06;hp=422254bb007d738d3513bafdae81970f64292b68;hpb=0441525690640ff374313fa5651a97829b0ea85a;p=rust.git

diff --git a/clippy_lints/src/needless_borrow.rs b/clippy_lints/src/needless_borrow.rs
index 422254bb007..3adbbfb8e89 100644
--- a/clippy_lints/src/needless_borrow.rs
+++ b/clippy_lints/src/needless_borrow.rs
@@ -2,10 +2,11 @@
 //!
 //! This lint is **warn** by default
 
-use crate::utils::{snippet_opt, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet_opt;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
-use rustc_hir::{BindingAnnotation, BorrowKind, Expr, ExprKind, HirId, Item, Mutability, Pat, PatKind};
+use rustc_hir::{BindingAnnotation, BorrowKind, Expr, ExprKind, Mutability, Pat, PatKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment};
@@ -18,32 +19,34 @@
     /// **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"
 }
 
 #[derive(Default)]
-pub struct NeedlessBorrow {
-    derived_item: Option<HirId>,
-}
+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<'_>) {
-        if e.span.from_expansion() || self.derived_item.is_some() {
+impl<'tcx> LateLintPass<'tcx> for NeedlessBorrow {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
+        if e.span.from_expansion() {
             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 ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, 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 +60,14 @@ 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,
@@ -75,15 +81,15 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) {
             }
         }
     }
-    fn check_pat(&mut self, cx: &LateContext<'a, 'tcx>, pat: &'tcx Pat<'_>) {
-        if pat.span.from_expansion() || self.derived_item.is_some() {
+    fn check_pat(&mut self, cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>) {
+        if pat.span.from_expansion() {
             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 {
@@ -92,9 +98,9 @@ fn check_pat(&mut self, cx: &LateContext<'a, 'tcx>, pat: &'tcx Pat<'_>) {
                     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,
@@ -106,19 +112,4 @@ 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))) {
-            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<'_>) {
-        if let Some(id) = self.derived_item {
-            if item.hir_id == id {
-                self.derived_item = None;
-            }
-        }
-    }
 }