about summary refs log tree commit diff
diff options
context:
space:
mode:
-rw-r--r--clippy_lints/src/dereference.rs79
-rw-r--r--tests/ui/explicit_auto_deref.fixed1
-rw-r--r--tests/ui/explicit_auto_deref.rs1
-rw-r--r--tests/ui/explicit_auto_deref.stderr118
4 files changed, 98 insertions, 101 deletions
diff --git a/clippy_lints/src/dereference.rs b/clippy_lints/src/dereference.rs
index b87d41455d9..8495d2c6df7 100644
--- a/clippy_lints/src/dereference.rs
+++ b/clippy_lints/src/dereference.rs
@@ -183,24 +183,24 @@ enum State {
     },
     DerefedBorrow(DerefedBorrow),
     ExplicitDeref {
-        // Span and id of the top-level deref expression if the parent expression is a borrow.
-        deref_span_id: Option<(Span, HirId)>,
+        mutability: Option<Mutability>,
     },
     ExplicitDerefField {
         name: Symbol,
     },
     Reborrow {
-        deref_span: Span,
-        deref_hir_id: HirId,
+        mutability: Mutability,
+    },
+    Borrow {
+        mutability: Mutability,
     },
-    Borrow,
 }
 
 // A reference operation considered by this lint pass
 enum RefOp {
     Method(Mutability),
     Deref,
-    AddrOf,
+    AddrOf(Mutability),
 }
 
 struct RefPat {
@@ -263,7 +263,7 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
                             ));
                         } else if position.is_deref_stable() {
                             self.state = Some((
-                                State::ExplicitDeref { deref_span_id: None },
+                                State::ExplicitDeref { mutability: None },
                                 StateData { span: expr.span, hir_id: expr.hir_id, position },
                             ));
                         }
@@ -289,7 +289,7 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
                             },
                         ));
                     },
-                    RefOp::AddrOf => {
+                    RefOp::AddrOf(mutability) => {
                         // Find the number of times the borrow is auto-derefed.
                         let mut iter = adjustments.iter();
                         let mut deref_count = 0usize;
@@ -359,7 +359,7 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
                             ));
                         } else if position.is_deref_stable() {
                             self.state = Some((
-                                State::Borrow,
+                                State::Borrow { mutability },
                                 StateData {
                                     span: expr.span,
                                     hir_id: expr.hir_id,
@@ -395,7 +395,7 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
                     data,
                 ));
             },
-            (Some((State::DerefedBorrow(state), data)), RefOp::AddrOf) if state.count != 0 => {
+            (Some((State::DerefedBorrow(state), data)), RefOp::AddrOf(_)) if state.count != 0 => {
                 self.state = Some((
                     State::DerefedBorrow(DerefedBorrow {
                         count: state.count - 1,
@@ -404,12 +404,12 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
                     data,
                 ));
             },
-            (Some((State::DerefedBorrow(state), data)), RefOp::AddrOf) => {
+            (Some((State::DerefedBorrow(state), data)), RefOp::AddrOf(mutability)) => {
                 let position = data.position;
                 report(cx, expr, State::DerefedBorrow(state), data);
                 if position.is_deref_stable() {
                     self.state = Some((
-                        State::Borrow,
+                        State::Borrow { mutability },
                         StateData {
                             span: expr.span,
                             hir_id: expr.hir_id,
@@ -430,43 +430,28 @@ impl<'tcx> LateLintPass<'tcx> for Dereferencing {
                     ));
                 } else if position.is_deref_stable() {
                     self.state = Some((
-                        State::ExplicitDeref { deref_span_id: None },
+                        State::ExplicitDeref { mutability: None },
                         StateData { span: expr.span, hir_id: expr.hir_id, position },
                     ));
                 }
             },
 
-            (Some((State::Borrow, data)), RefOp::Deref) => {
+            (Some((State::Borrow { mutability }, data)), RefOp::Deref) => {
                 if typeck.expr_ty(sub_expr).is_ref() {
-                    self.state = Some((
-                        State::Reborrow {
-                            deref_span: expr.span,
-                            deref_hir_id: expr.hir_id,
-                        },
-                        data,
-                    ));
+                    self.state = Some((State::Reborrow { mutability }, data));
                 } else {
                     self.state = Some((
                         State::ExplicitDeref {
-                            deref_span_id: Some((expr.span, expr.hir_id)),
+                            mutability: Some(mutability),
                         },
                         data,
                     ));
                 }
             },
-            (
-                Some((
-                    State::Reborrow {
-                        deref_span,
-                        deref_hir_id,
-                    },
-                    data,
-                )),
-                RefOp::Deref,
-            ) => {
+            (Some((State::Reborrow { mutability }, data)), RefOp::Deref) => {
                 self.state = Some((
                     State::ExplicitDeref {
-                        deref_span_id: Some((deref_span, deref_hir_id)),
+                        mutability: Some(mutability),
                     },
                     data,
                 ));
@@ -573,7 +558,7 @@ fn try_parse_ref_op<'tcx>(
         ExprKind::Unary(UnOp::Deref, sub_expr) if !typeck.expr_ty(sub_expr).is_unsafe_ptr() => {
             return Some((RefOp::Deref, sub_expr));
         },
-        ExprKind::AddrOf(BorrowKind::Ref, _, sub_expr) => return Some((RefOp::AddrOf, sub_expr)),
+        ExprKind::AddrOf(BorrowKind::Ref, mutability, sub_expr) => return Some((RefOp::AddrOf(mutability), sub_expr)),
         _ => return None,
     };
     if tcx.is_diagnostic_item(sym::deref_method, def_id) {
@@ -1074,7 +1059,7 @@ fn report<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, state: State, data
                 diag.span_suggestion(data.span, "change this to", sugg, app);
             });
         },
-        State::ExplicitDeref { deref_span_id } => {
+        State::ExplicitDeref { mutability } => {
             if matches!(
                 expr.kind,
                 ExprKind::Block(..)
@@ -1088,29 +1073,33 @@ fn report<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, state: State, data
                 return;
             }
 
-            let (span, hir_id, precedence) = if let Some((span, hir_id)) = deref_span_id
+            let (prefix, precedence) = if let Some(mutability) = mutability
                 && !cx.typeck_results().expr_ty(expr).is_ref()
             {
-                (span, hir_id, PREC_PREFIX)
+                let prefix = match mutability {
+                    Mutability::Not => "&",
+                    Mutability::Mut => "&mut ",
+                };
+                (prefix, 0)
             } else {
-                (data.span, data.hir_id, data.position.precedence())
+                ("", data.position.precedence())
             };
             span_lint_hir_and_then(
                 cx,
                 EXPLICIT_AUTO_DEREF,
-                hir_id,
-                span,
+                data.hir_id,
+                data.span,
                 "deref which would be done by auto-deref",
                 |diag| {
                     let mut app = Applicability::MachineApplicable;
-                    let (snip, snip_is_macro) = snippet_with_context(cx, expr.span, span.ctxt(), "..", &mut app);
+                    let (snip, snip_is_macro) = snippet_with_context(cx, expr.span, data.span.ctxt(), "..", &mut app);
                     let sugg =
                         if !snip_is_macro && expr.precedence().order() < precedence && !has_enclosing_paren(&snip) {
-                            format!("({})", snip)
+                            format!("{}({})", prefix, snip)
                         } else {
-                            snip.into()
+                            format!("{}{}", prefix, snip)
                         };
-                    diag.span_suggestion(span, "try this", sugg, app);
+                    diag.span_suggestion(data.span, "try this", sugg, app);
                 },
             );
         },
@@ -1141,7 +1130,7 @@ fn report<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, state: State, data
                 },
             );
         },
-        State::Borrow | State::Reborrow { .. } => (),
+        State::Borrow { .. } | State::Reborrow { .. } => (),
     }
 }
 
diff --git a/tests/ui/explicit_auto_deref.fixed b/tests/ui/explicit_auto_deref.fixed
index 327cfbaf324..d3efc299414 100644
--- a/tests/ui/explicit_auto_deref.fixed
+++ b/tests/ui/explicit_auto_deref.fixed
@@ -68,6 +68,7 @@ fn main() {
 
     let _: &str = &s;
     let _: &str = &{ String::new() };
+    let _: &str = &mut { String::new() };
     let _ = &*s; // Don't lint. Inferred type would change.
     let _: &_ = &*s; // Don't lint. Inferred type would change.
 
diff --git a/tests/ui/explicit_auto_deref.rs b/tests/ui/explicit_auto_deref.rs
index 471a03d60a9..e25ccbe78ce 100644
--- a/tests/ui/explicit_auto_deref.rs
+++ b/tests/ui/explicit_auto_deref.rs
@@ -68,6 +68,7 @@ fn main() {
 
     let _: &str = &*s;
     let _: &str = &*{ String::new() };
+    let _: &str = &mut *{ String::new() };
     let _ = &*s; // Don't lint. Inferred type would change.
     let _: &_ = &*s; // Don't lint. Inferred type would change.
 
diff --git a/tests/ui/explicit_auto_deref.stderr b/tests/ui/explicit_auto_deref.stderr
index d1bc51f5bdd..0d7a9564a90 100644
--- a/tests/ui/explicit_auto_deref.stderr
+++ b/tests/ui/explicit_auto_deref.stderr
@@ -1,208 +1,214 @@
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:69:20
+  --> $DIR/explicit_auto_deref.rs:69:19
    |
 LL |     let _: &str = &*s;
-   |                    ^^ help: try this: `s`
+   |                   ^^^ help: try this: `&s`
    |
    = note: `-D clippy::explicit-auto-deref` implied by `-D warnings`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:70:20
+  --> $DIR/explicit_auto_deref.rs:70:19
    |
 LL |     let _: &str = &*{ String::new() };
-   |                    ^^^^^^^^^^^^^^^^^^ help: try this: `{ String::new() }`
+   |                   ^^^^^^^^^^^^^^^^^^^ help: try this: `&{ String::new() }`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:74:12
+  --> $DIR/explicit_auto_deref.rs:71:19
+   |
+LL |     let _: &str = &mut *{ String::new() };
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut { String::new() }`
+
+error: deref which would be done by auto-deref
+  --> $DIR/explicit_auto_deref.rs:75:11
    |
 LL |     f_str(&*s);
-   |            ^^ help: try this: `s`
+   |           ^^^ help: try this: `&s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:78:14
+  --> $DIR/explicit_auto_deref.rs:79:13
    |
 LL |     f_str_t(&*s, &*s); // Don't lint second param.
-   |              ^^ help: try this: `s`
+   |             ^^^ help: try this: `&s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:81:25
+  --> $DIR/explicit_auto_deref.rs:82:24
    |
 LL |     let _: &Box<i32> = &**b;
-   |                         ^^^ help: try this: `b`
+   |                        ^^^^ help: try this: `&b`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:87:8
+  --> $DIR/explicit_auto_deref.rs:88:7
    |
 LL |     c(&*s);
-   |        ^^ help: try this: `s`
+   |       ^^^ help: try this: `&s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:93:9
+  --> $DIR/explicit_auto_deref.rs:94:9
    |
 LL |         &**x
    |         ^^^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:97:11
+  --> $DIR/explicit_auto_deref.rs:98:11
    |
 LL |         { &**x }
    |           ^^^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:101:9
+  --> $DIR/explicit_auto_deref.rs:102:9
    |
 LL |         &**{ x }
    |         ^^^^^^^^ help: try this: `{ x }`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:105:9
+  --> $DIR/explicit_auto_deref.rs:106:9
    |
 LL |         &***x
    |         ^^^^^ help: try this: `x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:122:13
+  --> $DIR/explicit_auto_deref.rs:123:12
    |
 LL |         f1(&*x);
-   |             ^^ help: try this: `x`
+   |            ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:123:13
+  --> $DIR/explicit_auto_deref.rs:124:12
    |
 LL |         f2(&*x);
-   |             ^^ help: try this: `x`
+   |            ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:124:13
+  --> $DIR/explicit_auto_deref.rs:125:12
    |
 LL |         f3(&*x);
-   |             ^^ help: try this: `x`
+   |            ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:125:28
+  --> $DIR/explicit_auto_deref.rs:126:27
    |
 LL |         f4.callable_str()(&*x);
-   |                            ^^ help: try this: `x`
+   |                           ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:126:13
+  --> $DIR/explicit_auto_deref.rs:127:12
    |
 LL |         f5(&*x);
-   |             ^^ help: try this: `x`
+   |            ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:127:13
+  --> $DIR/explicit_auto_deref.rs:128:12
    |
 LL |         f6(&*x);
-   |             ^^ help: try this: `x`
+   |            ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:128:28
+  --> $DIR/explicit_auto_deref.rs:129:27
    |
 LL |         f7.callable_str()(&*x);
-   |                            ^^ help: try this: `x`
+   |                           ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:129:26
+  --> $DIR/explicit_auto_deref.rs:130:25
    |
 LL |         f8.callable_t()(&*x);
-   |                          ^^ help: try this: `x`
+   |                         ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:130:13
+  --> $DIR/explicit_auto_deref.rs:131:12
    |
 LL |         f9(&*x);
-   |             ^^ help: try this: `x`
+   |            ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:131:14
+  --> $DIR/explicit_auto_deref.rs:132:13
    |
 LL |         f10(&*x);
-   |              ^^ help: try this: `x`
+   |             ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:132:27
+  --> $DIR/explicit_auto_deref.rs:133:26
    |
 LL |         f11.callable_t()(&*x);
-   |                           ^^ help: try this: `x`
+   |                          ^^^ help: try this: `&x`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:136:17
+  --> $DIR/explicit_auto_deref.rs:137:16
    |
 LL |     let _ = S1(&*s);
-   |                 ^^ help: try this: `s`
+   |                ^^^ help: try this: `&s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:141:22
+  --> $DIR/explicit_auto_deref.rs:142:21
    |
 LL |     let _ = S2 { s: &*s };
-   |                      ^^ help: try this: `s`
+   |                     ^^^ help: try this: `&s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:157:30
+  --> $DIR/explicit_auto_deref.rs:158:30
    |
 LL |             let _ = Self::S1(&**s);
    |                              ^^^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:158:35
+  --> $DIR/explicit_auto_deref.rs:159:35
    |
 LL |             let _ = Self::S2 { s: &**s };
    |                                   ^^^^ help: try this: `s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:161:21
+  --> $DIR/explicit_auto_deref.rs:162:20
    |
 LL |     let _ = E1::S1(&*s);
-   |                     ^^ help: try this: `s`
+   |                    ^^^ help: try this: `&s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:162:26
+  --> $DIR/explicit_auto_deref.rs:163:25
    |
 LL |     let _ = E1::S2 { s: &*s };
-   |                          ^^ help: try this: `s`
+   |                         ^^^ help: try this: `&s`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:180:13
+  --> $DIR/explicit_auto_deref.rs:181:13
    |
 LL |     let _ = (*b).foo;
    |             ^^^^ help: try this: `b`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:181:13
+  --> $DIR/explicit_auto_deref.rs:182:13
    |
 LL |     let _ = (**b).foo;
    |             ^^^^^ help: try this: `b`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:196:19
+  --> $DIR/explicit_auto_deref.rs:197:19
    |
 LL |     let _ = f_str(*ref_str);
    |                   ^^^^^^^^ help: try this: `ref_str`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:198:19
+  --> $DIR/explicit_auto_deref.rs:199:19
    |
 LL |     let _ = f_str(**ref_ref_str);
    |                   ^^^^^^^^^^^^^ help: try this: `ref_ref_str`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:208:13
+  --> $DIR/explicit_auto_deref.rs:209:13
    |
 LL |     f_str(&&*ref_str); // `needless_borrow` will suggest removing both references
    |             ^^^^^^^^ help: try this: `ref_str`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:209:12
+  --> $DIR/explicit_auto_deref.rs:210:12
    |
 LL |     f_str(&&**ref_str); // `needless_borrow` will suggest removing only one reference
    |            ^^^^^^^^^^ help: try this: `ref_str`
 
 error: deref which would be done by auto-deref
-  --> $DIR/explicit_auto_deref.rs:218:41
+  --> $DIR/explicit_auto_deref.rs:219:41
    |
 LL |     let _ = || -> &'static str { return *s };
    |                                         ^^ help: try this: `s`
 
-error: aborting due to 34 previous errors
+error: aborting due to 35 previous errors