Auto merge of #4938 - flip1995:rustup, r=flip1995

[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 d8f892d40735855c5f0dfc4aa5877abeeda93490..6e18501480b6043bc5d0ebaea57fd36446db195f 100644 (file)
--- a/clippy_lints/src/needless_borrow.rs
+++ b/clippy_lints/src/needless_borrow.rs
@@ -2,53 +2,53 @@
 //!
 //! This lint is **warn** by default
 
-use rustc::lint::*;
-use rustc::hir::{BindingAnnotation, Expr, ExprAddrOf, MutImmutable, Pat, PatKind};
+use crate::utils::{snippet_opt, span_lint_and_then};
+use if_chain::if_chain;
+use rustc::hir::{BindingAnnotation, BorrowKind, Expr, ExprKind, HirId, Item, Mutability, Pat, PatKind};
+use rustc::impl_lint_pass;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
 use rustc::ty;
 use rustc::ty::adjustment::{Adjust, Adjustment};
-use utils::{in_macro, snippet_opt, span_lint_and_then};
+use rustc_errors::Applicability;
+use rustc_session::declare_tool_lint;
 
-/// **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.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// let x: &i32 = &&&&&&5;
-/// ```
-declare_lint! {
+declare_clippy_lint! {
+    /// **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.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// let x: &i32 = &&&&&&5;
+    /// ```
+    ///
+    /// **Known problems:** None.
     pub NEEDLESS_BORROW,
-    Warn,
+    nursery,
     "taking a reference that is going to be automatically dereferenced"
 }
 
-#[derive(Copy, Clone)]
-pub struct NeedlessBorrow;
-
-impl LintPass for NeedlessBorrow {
-    fn get_lints(&self) -> LintArray {
-        lint_array!(NEEDLESS_BORROW)
-    }
+#[derive(Default)]
+pub struct NeedlessBorrow {
+    derived_item: Option<HirId>,
 }
 
+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 in_macro(e.span) {
+        if e.span.from_expansion() || self.derived_item.is_some() {
             return;
         }
-        if let ExprAddrOf(MutImmutable, ref inner) = e.node {
-            if let ty::TyRef(..) = cx.tables.expr_ty(inner).sty {
+        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 [Adjustment {
-                        kind: Adjust::Deref(_),
-                        ..
+                        kind: Adjust::Deref(_), ..
                     }, Adjustment {
-                        kind: Adjust::Deref(_),
-                        ..
+                        kind: Adjust::Deref(_), ..
                     }, Adjustment {
                         kind: Adjust::Borrow(_),
                         ..
@@ -62,9 +62,14 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
                              by the compiler",
                             |db| {
                                 if let Some(snippet) = snippet_opt(cx, inner.span) {
-                                    db.span_suggestion(e.span, "change this to", snippet);
+                                    db.span_suggestion(
+                                        e.span,
+                                        "change this to",
+                                        snippet,
+                                        Applicability::MachineApplicable,
+                                    );
                                 }
-                            }
+                            },
                         );
                     }
                 }
@@ -72,28 +77,49 @@ 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 in_macro(pat.span) {
+        if pat.span.from_expansion() || self.derived_item.is_some() {
             return;
         }
-        if_let_chain! {[
-            let PatKind::Binding(BindingAnnotation::Ref, _, name, _) = pat.node,
-            let ty::TyRef(_, ref tam) = cx.tables.pat_ty(pat).sty,
-            tam.mutbl == MutImmutable,
-            let ty::TyRef(_, ref tam) = tam.ty.sty,
+        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::Not;
+            if let ty::Ref(_, _, mutbl) = tam.kind;
             // only lint immutable refs, because borrowed `&mut T` cannot be moved out
-            tam.mutbl == MutImmutable,
-        ], {
-            span_lint_and_then(
-                cx,
-                NEEDLESS_BORROW,
-                pat.span,
-                "this pattern creates a reference to a reference",
-                |db| {
-                    if let Some(snippet) = snippet_opt(cx, name.span) {
-                        db.span_suggestion(pat.span, "change this to", snippet);
+            if mutbl == Mutability::Not;
+            then {
+                span_lint_and_then(
+                    cx,
+                    NEEDLESS_BORROW,
+                    pat.span,
+                    "this pattern creates a reference to a reference",
+                    |db| {
+                        if let Some(snippet) = snippet_opt(cx, name.span) {
+                            db.span_suggestion(
+                                pat.span,
+                                "change this to",
+                                snippet,
+                                Applicability::MachineApplicable,
+                            );
+                        }
                     }
-                }
-            )
-        }}
+                )
+            }
+        }
+    }
+
+    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;
+            }
+        }
     }
 }