Verbose suggestions

Author: estebank

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -377,10 +377,10 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     err.span_label(span, format!("cannot {act}"));
                 }
                 if suggest {
-                    err.span_suggestion(
-                        local_decl.source_info.span,
+                    err.span_suggestion_verbose(
+                        local_decl.source_info.span.shrink_to_lo(),
                         "consider changing this to be mutable",
-                        format!("mut {}", self.local_names[local].unwrap()),
+                        "mut ".to_string(),
                         Applicability::MachineApplicable,
                     );
                     let tcx = self.infcx.tcx;

src/test/ui/asm/aarch64/type-check-2-2.rs

@@ -25,12 +25,10 @@ fn main() {
 
         // Outputs require mutable places
 
-        let v: Vec<u64> = vec![0, 1, 2];
+        let v: Vec<u64> = vec![0, 1, 2]; //~ ERROR cannot borrow `v` as mutable
         asm!("{}", in(reg) v[0]);
         asm!("{}", out(reg) v[0]);
-        //~^ ERROR cannot borrow `v` as mutable, as it is not declared as mutable
         asm!("{}", inout(reg) v[0]);
-        //~^ ERROR cannot borrow `v` as mutable, as it is not declared as mutable
 
         // Sym operands must point to a function or static
     }

src/test/ui/asm/aarch64/type-check-2-2.stderr

@@ -25,24 +25,22 @@ LL |         let mut y: u64 = 0;
    |                        +++
 
 error[E0596]: cannot borrow `v` as mutable, as it is not declared as mutable
-  --> $DIR/type-check-2-2.rs:30:29
+  --> $DIR/type-check-2-2.rs:28:13
    |
 LL |         let v: Vec<u64> = vec![0, 1, 2];
-   |             - help: consider changing this to be mutable: `mut v`
+   |             ^ not mutable
 LL |         asm!("{}", in(reg) v[0]);
 LL |         asm!("{}", out(reg) v[0]);
-   |                             ^ cannot borrow as mutable
-
-error[E0596]: cannot borrow `v` as mutable, as it is not declared as mutable
-  --> $DIR/type-check-2-2.rs:32:31
-   |
-LL |         let v: Vec<u64> = vec![0, 1, 2];
-   |             - help: consider changing this to be mutable: `mut v`
-...
+   |                             - cannot borrow as mutable
 LL |         asm!("{}", inout(reg) v[0]);
-   |                               ^ cannot borrow as mutable
+   |                               - cannot borrow as mutable
+   |
+help: consider changing this to be mutable
+   |
+LL |         let mut v: Vec<u64> = vec![0, 1, 2];
+   |             +++
 
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
 Some errors have detailed explanations: E0381, E0596.
 For more information about an error, try `rustc --explain E0381`.

src/test/ui/asm/x86_64/type-check-5.stderr

@@ -28,15 +28,17 @@ error[E0596]: cannot borrow `v` as mutable, as it is not declared as mutable
   --> $DIR/type-check-5.rs:24:13
    |
 LL |         let v: Vec<u64> = vec![0, 1, 2];
-   |             ^
-   |             |
-   |             not mutable
-   |             help: consider changing this to be mutable: `mut v`
+   |             ^ not mutable
 ...
 LL |         asm!("{}", out(reg) v[0]);
    |                             - cannot borrow as mutable
 LL |         asm!("{}", inout(reg) v[0]);
    |                               - cannot borrow as mutable
+   |
+help: consider changing this to be mutable
+   |
+LL |         let mut v: Vec<u64> = vec![0, 1, 2];
+   |             +++
 
 error: aborting due to 3 previous errors
 

src/test/ui/async-await/issue-61452.stderr

@@ -1,10 +1,13 @@
 error[E0596]: cannot borrow `x` as mutable, as it is not declared as mutable
   --> $DIR/issue-61452.rs:4:5
    |
-LL | pub async fn f(x: Option<usize>) {
-   |                - help: consider changing this to be mutable: `mut x`
 LL |     x.take();
    |     ^^^^^^^^ cannot borrow as mutable
+   |
+help: consider changing this to be mutable
+   |
+LL | pub async fn f(mut x: Option<usize>) {
+   |                +++
 
 error[E0384]: cannot assign twice to immutable variable `x`
   --> $DIR/issue-61452.rs:9:5

src/test/ui/async-await/issues/issue-61187.stderr

@@ -1,10 +1,13 @@
 error[E0596]: cannot borrow `data` as mutable, as it is not declared as mutable
   --> $DIR/issue-61187.rs:6:5
    |
-LL | async fn response(data: Vec<u8>) {
-   |                   ---- help: consider changing this to be mutable: `mut data`
 LL |     data.reverse();
    |     ^^^^^^^^^^^^^^ cannot borrow as mutable
+   |
+help: consider changing this to be mutable
+   |
+LL | async fn response(mut data: Vec<u8>) {
+   |                   +++
 
 error: aborting due to previous error
 

src/test/ui/augmented-assignments.rs

@@ -19,7 +19,7 @@ fn main() {
 
     let y = Int(2);
     //~^ HELP consider changing this to be mutable
-    //~| SUGGESTION mut y
+    //~| SUGGESTION mut
     y   //~ ERROR cannot borrow `y` as mutable, as it is not declared as mutable
         //~| cannot borrow as mutable
     +=

src/test/ui/augmented-assignments.stderr

@@ -10,11 +10,13 @@ LL |     x;
 error[E0596]: cannot borrow `y` as mutable, as it is not declared as mutable
   --> $DIR/augmented-assignments.rs:23:5
    |
-LL |     let y = Int(2);
-   |         - help: consider changing this to be mutable: `mut y`
-...
 LL |     y
    |     ^ cannot borrow as mutable
+   |
+help: consider changing this to be mutable
+   |
+LL |     let mut y = Int(2);
+   |         +++
 
 error: aborting due to 2 previous errors
 

src/test/ui/borrowck/borrow-raw-address-of-mutability.stderr

@@ -1,10 +1,13 @@
 error[E0596]: cannot borrow `x` as mutable, as it is not declared as mutable
   --> $DIR/borrow-raw-address-of-mutability.rs:5:13
    |
-LL |     let x = 0;
-   |         - help: consider changing this to be mutable: `mut x`
 LL |     let y = &raw mut x;
    |             ^^^^^^^^^^ cannot borrow as mutable
+   |
+help: consider changing this to be mutable
+   |
+LL |     let mut x = 0;
+   |         +++
 
 error[E0596]: cannot borrow `x` as mutable, as it is not declared as mutable
   --> $DIR/borrow-raw-address-of-mutability.rs:11:17
@@ -18,13 +21,16 @@ LL |         let y = &raw mut x;
 error[E0596]: cannot borrow `f` as mutable, as it is not declared as mutable
   --> $DIR/borrow-raw-address-of-mutability.rs:21:5
    |
-LL |     let f = || {
-   |         - help: consider changing this to be mutable: `mut f`
 LL |         let y = &raw mut x;
    |                          - calling `f` requires mutable binding due to mutable borrow of `x`
 LL |     };
 LL |     f();
    |     ^ cannot borrow as mutable
+   |
+help: consider changing this to be mutable
+   |
+LL |     let mut f = || {
+   |         +++
 
 error[E0596]: cannot borrow `x` as mutable, as it is a captured variable in a `Fn` closure
   --> $DIR/borrow-raw-address-of-mutability.rs:29:17

src/test/ui/borrowck/borrowck-access-permissions.stderr

@@ -1,11 +1,13 @@
 error[E0596]: cannot borrow `x` as mutable, as it is not declared as mutable
   --> $DIR/borrowck-access-permissions.rs:9:19
    |
-LL |     let x = 1;
-   |         - help: consider changing this to be mutable: `mut x`
-...
 LL |         let _y1 = &mut x;
    |                   ^^^^^^ cannot borrow as mutable
+   |
+help: consider changing this to be mutable
+   |
+LL |     let mut x = 1;
+   |         +++
 
 error[E0596]: cannot borrow immutable static item `static_x` as mutable
   --> $DIR/borrowck-access-permissions.rs:14:19
@@ -16,11 +18,13 @@ LL |         let _y1 = &mut static_x;
 error[E0596]: cannot borrow `*box_x` as mutable, as `box_x` is not declared as mutable
   --> $DIR/borrowck-access-permissions.rs:22:19
    |
-LL |         let box_x = Box::new(1);
-   |             ----- help: consider changing this to be mutable: `mut box_x`
-...
 LL |         let _y1 = &mut *box_x;
    |                   ^^^^^^^^^^^ cannot borrow as mutable
+   |
+help: consider changing this to be mutable
+   |
+LL |         let mut box_x = Box::new(1);
+   |             +++
 
 error[E0596]: cannot borrow `*ref_x` as mutable, as it is behind a `&` reference
   --> $DIR/borrowck-access-permissions.rs:30:19