span_suggestion

Author: lengyijun

clippy_lints/src/borrow_deref_ref.rs

@@ -3,6 +3,7 @@ use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::source::snippet_opt;
 use clippy_utils::ty::implements_trait;
 use clippy_utils::{get_parent_expr, is_lint_allowed};
+use rustc_errors::Applicability;
 use rustc_hir::{ExprKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::mir::Mutability;
@@ -82,11 +83,11 @@ impl LateLintPass<'_> for BorrowDerefRef {
                     e.span,
                     "deref on an immutable reference",
                     |diag| {
-                        diag.help(
-                            &format!(
-                                "consider using `{}` if you would like to reborrow",
-                                &snippet_opt(cx, deref_target.span).unwrap(),
-                             )
+                        diag.span_suggestion(
+                            e.span,
+                            "if you would like to reborrow, try removing `&*`",
+                            snippet_opt(cx, deref_target.span).unwrap(),
+                            Applicability::MachineApplicable
                         );
 
                         // has deref trait -> give 2 help
@@ -97,11 +98,14 @@ impl LateLintPass<'_> for BorrowDerefRef {
                             }
                         }
 
-                        diag.help(
-                            &format!(
-                                "consider using `&**{}` if you would like to deref",
+                        diag.span_suggestion(
+                            e.span,
+                            "if you would like to deref, try using `&**`",
+                            format!(
+                                "&**{}",
                                 &snippet_opt(cx, deref_target.span).unwrap(),
-                             )
+                             ),
+                            Applicability::MachineApplicable
                         );
 
                     }

tests/ui/borrow_deref_ref.stderr

@@ -2,35 +2,36 @@ error: deref on an immutable reference
   --> $DIR/borrow_deref_ref.rs:6:17
    |
 LL |         let b = &*a;
-   |                 ^^^
+   |                 ^^^ help: if you would like to reborrow, try removing `&*`: `a`
    |
    = note: `-D clippy::borrow-deref-ref` implied by `-D warnings`
-   = help: consider using `a` if you would like to reborrow
 
 error: deref on an immutable reference
   --> $DIR/borrow_deref_ref.rs:9:23
    |
 LL |         let x: &str = &*s;
    |                       ^^^
    |
-   = help: consider using `s` if you would like to reborrow
-   = help: consider using `&**s` if you would like to deref
+help: if you would like to reborrow, try removing `&*`
+   |
+LL |         let x: &str = s;
+   |                       ~
+help: if you would like to deref, try using `&**`
+   |
+LL |         let x: &str = &**s;
+   |                       ~~~~
 
 error: deref on an immutable reference
   --> $DIR/borrow_deref_ref.rs:11:22
    |
 LL |         let b = &mut &*bar(&12);
-   |                      ^^^^^^^^^^
-   |
-   = help: consider using `bar(&12)` if you would like to reborrow
+   |                      ^^^^^^^^^^ help: if you would like to reborrow, try removing `&*`: `bar(&12)`
 
 error: deref on an immutable reference
   --> $DIR/borrow_deref_ref.rs:54:23
    |
 LL |         let addr_y = &&*x as *const _ as usize; // assert ok
-   |                       ^^^
-   |
-   = help: consider using `x` if you would like to reborrow
+   |                       ^^^ help: if you would like to reborrow, try removing `&*`: `x`
 
 error: aborting due to 4 previous errors