span_suggestion

src/librustc_borrowck/borrowck/mod.rs

@@ -1215,9 +1215,10 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                             } else {
                                 snippet
                             };
-                            db.span_label(
+                            db.span_suggestion(
                                 let_span,
-                                format!("consider changing this to `{}`", replace_str)
+                                "use a mutable reference instead",
+                                replace_str,
                             );
                         };
                     }

src/test/ui/nll/issue-51244.rs

@@ -0,0 +1,16 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(nll)]
+
+fn main() {
+    let ref my_ref @ _ = 0;
+    *my_ref = 0; //~ ERROR cannot assign to data in a `&` reference [E0594]
+}

src/test/ui/nll/issue-51244.stderr

@@ -1,9 +1,9 @@
 error[E0594]: cannot assign to data in a `&` reference
-  --> $DIR/issue-51244.rs:13:5
+  --> $DIR/issue-51244.rs:15:5
    |
 LL |     let ref my_ref @ _ = 0;
    |         -------------- help: consider changing this to be a mutable reference: `&mut ef my_ref @ _`
-LL |     *my_ref = 0; //~ ERROR cannot assign to immutable borrowed content `*my_ref` [E0594]
+LL |     *my_ref = 0; //~ ERROR cannot assign to data in a `&` reference [E0594]
    |     ^^^^^^^^^^^
 
 error: aborting due to previous error

src/test/ui/rfc-2005-default-binding-mode/enum.stderr

@@ -2,7 +2,7 @@ error[E0594]: cannot assign to immutable borrowed content `*x`
   --> $DIR/enum.rs:19:5
    |
 LL |     let Wrap(x) = &Wrap(3);
-   |              - consider changing this to `x`
+   |              - help: use a mutable reference instead: `x`
 LL |     *x += 1; //~ ERROR cannot assign to immutable
    |     ^^^^^^^ cannot borrow as mutable
 
@@ -10,7 +10,7 @@ error[E0594]: cannot assign to immutable borrowed content `*x`
   --> $DIR/enum.rs:23:9
    |
 LL |     if let Some(x) = &Some(3) {
-   |                 - consider changing this to `x`
+   |                 - help: use a mutable reference instead: `x`
 LL |         *x += 1; //~ ERROR cannot assign to immutable
    |         ^^^^^^^ cannot borrow as mutable
 
@@ -18,7 +18,7 @@ error[E0594]: cannot assign to immutable borrowed content `*x`
   --> $DIR/enum.rs:29:9
    |
 LL |     while let Some(x) = &Some(3) {
-   |                    - consider changing this to `x`
+   |                    - help: use a mutable reference instead: `x`
 LL |         *x += 1; //~ ERROR cannot assign to immutable
    |         ^^^^^^^ cannot borrow as mutable
 

src/test/ui/rfc-2005-default-binding-mode/explicit-mut.stderr

@@ -2,7 +2,7 @@ error[E0594]: cannot assign to immutable borrowed content `*n`
   --> $DIR/explicit-mut.rs:17:13
    |
 LL |         Some(n) => {
-   |              - consider changing this to `n`
+   |              - help: use a mutable reference instead: `n`
 LL |             *n += 1; //~ ERROR cannot assign to immutable
    |             ^^^^^^^ cannot borrow as mutable
 
@@ -10,7 +10,7 @@ error[E0594]: cannot assign to immutable borrowed content `*n`
   --> $DIR/explicit-mut.rs:25:13
    |
 LL |         Some(n) => {
-   |              - consider changing this to `n`
+   |              - help: use a mutable reference instead: `n`
 LL |             *n += 1; //~ ERROR cannot assign to immutable
    |             ^^^^^^^ cannot borrow as mutable
 
@@ -18,7 +18,7 @@ error[E0594]: cannot assign to immutable borrowed content `*n`
   --> $DIR/explicit-mut.rs:33:13
    |
 LL |         Some(n) => {
-   |              - consider changing this to `n`
+   |              - help: use a mutable reference instead: `n`
 LL |             *n += 1; //~ ERROR cannot assign to immutable
    |             ^^^^^^^ cannot borrow as mutable
 

src/test/ui/suggestions/issue-51244.stderr

@@ -2,7 +2,7 @@ error[E0594]: cannot assign to immutable borrowed content `*my_ref`
   --> $DIR/issue-51244.rs:13:5
    |
 LL |     let ref my_ref @ _ = 0;
-   |         -------------- consider changing this to `ref mut my_ref @ _`
+   |         -------------- help: use a mutable reference instead: `ref mut my_ref @ _`
 LL |     *my_ref = 0; //~ ERROR cannot assign to immutable borrowed content `*my_ref` [E0594]
    |     ^^^^^^^^^^^ cannot borrow as mutable