NLL: Updates to diagnostic output in test/ui.

pnkfelix · pnkfelix · commit 2d4df5b53e92 · 2018-06-19T19:38:37.000+02:00
diff --git a/src/test/ui/augmented-assignments.nll.stderr b/src/test/ui/augmented-assignments.nll.stderr
@@ -17,6 +17,9 @@ LL | |     x;  //~ value moved here
 error[E0596]: cannot borrow immutable item `y` as mutable
   --> $DIR/augmented-assignments.rs:30:5
    |
+LL |     let y = Int(2);
+   |         - help: consider changing this to be mutable: `mut y`
+LL |     //~^ consider changing this to `mut y`
 LL |     y   //~ error: cannot borrow immutable local variable `y` as mutable
    |     ^ cannot borrow as mutable
 
diff --git a/src/test/ui/borrowck/issue-45983.nll.stderr b/src/test/ui/borrowck/issue-45983.nll.stderr
@@ -14,13 +14,13 @@ error[E0594]: cannot assign to immutable item `x`
   --> $DIR/issue-45983.rs:17:18
    |
 LL |     give_any(|y| x = Some(y));
-   |                  ^^^^^^^^^^^ cannot mutate
-   |
-   = note: the value which is causing this path not to be mutable is...: `x`
+   |                  ^^^^^^^^^^^ cannot assign
 
 error[E0596]: cannot borrow immutable item `x` as mutable
   --> $DIR/issue-45983.rs:17:14
    |
+LL |     let x = None;
+   |         - help: consider changing this to be mutable: `mut x`
 LL |     give_any(|y| x = Some(y));
    |              ^^^^^^^^^^^^^^^ cannot borrow as mutable
 
diff --git a/src/test/ui/borrowck/mut-borrow-of-mut-ref.nll.stderr b/src/test/ui/borrowck/mut-borrow-of-mut-ref.nll.stderr
@@ -1,6 +1,8 @@
 error[E0596]: cannot borrow immutable item `b` as mutable
   --> $DIR/mut-borrow-of-mut-ref.rs:18:7
    |
+LL | fn f(b: &mut i32) {
+   |      - help: consider changing this to be mutable: `mut b`
 LL |     g(&mut b) //~ ERROR cannot borrow
    |       ^^^^^^ cannot borrow as mutable
 
diff --git a/src/test/ui/codemap_tests/huge_multispan_highlight.nll.stderr b/src/test/ui/codemap_tests/huge_multispan_highlight.nll.stderr
@@ -1,6 +1,9 @@
 error[E0596]: cannot borrow immutable item `x` as mutable
   --> $DIR/huge_multispan_highlight.rs:100:13
    |
+LL |     let x = "foo";
+   |         - help: consider changing this to be mutable: `mut x`
+...
 LL |     let y = &mut x; //~ ERROR cannot borrow
    |             ^^^^^^ cannot borrow as mutable
 
diff --git a/src/test/ui/did_you_mean/issue-31424.nll.stderr b/src/test/ui/did_you_mean/issue-31424.nll.stderr
@@ -7,6 +7,8 @@ LL |         (&mut self).bar(); //~ ERROR cannot borrow
 error[E0596]: cannot borrow immutable item `self` as mutable
   --> $DIR/issue-31424.rs:23:9
    |
+LL |     fn bar(self: &mut Self) {
+   |            ---- help: consider changing this to be mutable: `mut self`
 LL |         (&mut self).bar(); //~ ERROR cannot borrow
    |         ^^^^^^^^^^^ cannot borrow as mutable
 
diff --git a/src/test/ui/did_you_mean/issue-34126.nll.stderr b/src/test/ui/did_you_mean/issue-34126.nll.stderr
@@ -2,7 +2,10 @@ error[E0596]: cannot borrow immutable item `self` as mutable
   --> $DIR/issue-34126.rs:16:18
    |
 LL |         self.run(&mut self); //~ ERROR cannot borrow
-   |                  ^^^^^^^^^ cannot borrow as mutable
+   |                  ^^^^^^^^^
+   |                  |
+   |                  cannot borrow as mutable
+   |                  try removing `&mut` here
 
 error[E0502]: cannot borrow `self` as mutable because it is also borrowed as immutable
   --> $DIR/issue-34126.rs:16:18
diff --git a/src/test/ui/did_you_mean/issue-34337.nll.stderr b/src/test/ui/did_you_mean/issue-34337.nll.stderr
@@ -2,7 +2,10 @@ error[E0596]: cannot borrow immutable item `key` as mutable
   --> $DIR/issue-34337.rs:16:9
    |
 LL |     get(&mut key); //~ ERROR cannot borrow
-   |         ^^^^^^^^ cannot borrow as mutable
+   |         ^^^^^^^^
+   |         |
+   |         cannot borrow as mutable
+   |         try removing `&mut` here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/did_you_mean/issue-35937.nll.stderr b/src/test/ui/did_you_mean/issue-35937.nll.stderr
@@ -1,10 +1,10 @@
 error[E0596]: cannot borrow immutable item `f.v` as mutable
   --> $DIR/issue-35937.rs:17:5
    |
+LL |     let f = Foo { v: Vec::new() };
+   |         - help: consider changing this to be mutable: `mut f`
 LL |     f.v.push("cat".to_string()); //~ ERROR cannot borrow
    |     ^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `f`
 
 error[E0384]: cannot assign twice to immutable variable `s.x`
   --> $DIR/issue-35937.rs:26:5
diff --git a/src/test/ui/did_you_mean/issue-37139.nll.stderr b/src/test/ui/did_you_mean/issue-37139.nll.stderr
@@ -2,7 +2,10 @@ error[E0596]: cannot borrow immutable item `x` as mutable
   --> $DIR/issue-37139.rs:22:18
    |
 LL |             test(&mut x); //~ ERROR cannot borrow immutable
-   |                  ^^^^^^ cannot borrow as mutable
+   |                  ^^^^^^
+   |                  |
+   |                  cannot borrow as mutable
+   |                  try removing `&mut` here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/did_you_mean/issue-38147-1.nll.stderr b/src/test/ui/did_you_mean/issue-38147-1.nll.stderr
@@ -1,10 +1,10 @@
 error[E0596]: cannot borrow immutable item `*self.s` as mutable
   --> $DIR/issue-38147-1.rs:27:9
    |
+LL |     fn f(&self) {
+   |          ----- help: consider changing this to be a mutable reference: `&mut Foo<'_>`
 LL |         self.s.push('x'); //~ ERROR cannot borrow data mutably
-   |         ^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*self`
+   |         ^^^^^^ `self` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/did_you_mean/issue-38147-4.nll.stderr b/src/test/ui/did_you_mean/issue-38147-4.nll.stderr
@@ -1,10 +1,10 @@
 error[E0596]: cannot borrow immutable item `*f.s` as mutable
   --> $DIR/issue-38147-4.rs:16:5
    |
+LL | fn f(x: usize, f: &Foo) {
+   |                   ---- help: consider changing this to be a mutable reference: `&mut Foo<'_>`
 LL |     f.s.push('x'); //~ ERROR cannot borrow data mutably
-   |     ^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*f`
+   |     ^^^ `f` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/did_you_mean/issue-39544.nll.stderr b/src/test/ui/did_you_mean/issue-39544.nll.stderr
@@ -1,96 +1,100 @@
 error[E0596]: cannot borrow immutable item `z.x` as mutable
   --> $DIR/issue-39544.rs:21:13
    |
+LL |     let z = Z { x: X::Y };
+   |         - help: consider changing this to be mutable: `mut z`
 LL |     let _ = &mut z.x; //~ ERROR cannot borrow
    |             ^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `z`
 
 error[E0596]: cannot borrow immutable item `self.x` as mutable
   --> $DIR/issue-39544.rs:26:17
    |
+LL |     fn foo<'z>(&'z self) {
+   |                -------- help: consider changing this to be a mutable reference: `&mut Z`
 LL |         let _ = &mut self.x; //~ ERROR cannot borrow
-   |                 ^^^^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*self`
+   |                 ^^^^^^^^^^^ `self` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error[E0596]: cannot borrow immutable item `self.x` as mutable
   --> $DIR/issue-39544.rs:30:17
    |
+LL |     fn foo1(&self, other: &Z) {
+   |             ----- help: consider changing this to be a mutable reference: `&mut Z`
 LL |         let _ = &mut self.x; //~ ERROR cannot borrow
-   |                 ^^^^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*self`
+   |                 ^^^^^^^^^^^ `self` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error[E0596]: cannot borrow immutable item `other.x` as mutable
   --> $DIR/issue-39544.rs:31:17
    |
+LL |     fn foo1(&self, other: &Z) {
+   |                           -- help: consider changing this to be a mutable reference: `&mut Z`
+LL |         let _ = &mut self.x; //~ ERROR cannot borrow
 LL |         let _ = &mut other.x; //~ ERROR cannot borrow
-   |                 ^^^^^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*other`
+   |                 ^^^^^^^^^^^^ `other` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error[E0596]: cannot borrow immutable item `self.x` as mutable
   --> $DIR/issue-39544.rs:35:17
    |
+LL |     fn foo2<'a>(&'a self, other: &Z) {
+   |                 -------- help: consider changing this to be a mutable reference: `&mut Z`
 LL |         let _ = &mut self.x; //~ ERROR cannot borrow
-   |                 ^^^^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*self`
+   |                 ^^^^^^^^^^^ `self` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error[E0596]: cannot borrow immutable item `other.x` as mutable
   --> $DIR/issue-39544.rs:36:17
    |
+LL |     fn foo2<'a>(&'a self, other: &Z) {
+   |                                  -- help: consider changing this to be a mutable reference: `&mut Z`
+LL |         let _ = &mut self.x; //~ ERROR cannot borrow
 LL |         let _ = &mut other.x; //~ ERROR cannot borrow
-   |                 ^^^^^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*other`
+   |                 ^^^^^^^^^^^^ `other` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error[E0596]: cannot borrow immutable item `self.x` as mutable
   --> $DIR/issue-39544.rs:40:17
    |
+LL |     fn foo3<'a>(self: &'a Self, other: &Z) {
+   |                       -------- help: consider changing this to be a mutable reference: `&mut Z`
 LL |         let _ = &mut self.x; //~ ERROR cannot borrow
-   |                 ^^^^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*self`
+   |                 ^^^^^^^^^^^ `self` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error[E0596]: cannot borrow immutable item `other.x` as mutable
   --> $DIR/issue-39544.rs:41:17
    |
+LL |     fn foo3<'a>(self: &'a Self, other: &Z) {
+   |                                        -- help: consider changing this to be a mutable reference: `&mut Z`
+LL |         let _ = &mut self.x; //~ ERROR cannot borrow
 LL |         let _ = &mut other.x; //~ ERROR cannot borrow
-   |                 ^^^^^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*other`
+   |                 ^^^^^^^^^^^^ `other` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error[E0596]: cannot borrow immutable item `other.x` as mutable
   --> $DIR/issue-39544.rs:45:17
    |
+LL |     fn foo4(other: &Z) {
+   |                    -- help: consider changing this to be a mutable reference: `&mut Z`
 LL |         let _ = &mut other.x; //~ ERROR cannot borrow
-   |                 ^^^^^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*other`
+   |                 ^^^^^^^^^^^^ `other` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error[E0596]: cannot borrow immutable item `z.x` as mutable
   --> $DIR/issue-39544.rs:51:13
    |
+LL | pub fn with_arg(z: Z, w: &Z) {
+   |                 - help: consider changing this to be mutable: `mut z`
 LL |     let _ = &mut z.x; //~ ERROR cannot borrow
    |             ^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `z`
 
 error[E0596]: cannot borrow immutable item `w.x` as mutable
   --> $DIR/issue-39544.rs:52:13
    |
+LL | pub fn with_arg(z: Z, w: &Z) {
+   |                          -- help: consider changing this to be a mutable reference: `&mut Z`
+LL |     let _ = &mut z.x; //~ ERROR cannot borrow
 LL |     let _ = &mut w.x; //~ ERROR cannot borrow
-   |             ^^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `*w`
+   |             ^^^^^^^^ `w` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
-error[E0594]: cannot assign to immutable item `*x.0`
+error[E0594]: cannot assign to `*x.0` which is behind a `&` reference
   --> $DIR/issue-39544.rs:58:5
    |
 LL |     *x.0 = 1;
-   |     ^^^^^^^^ cannot mutate
+   |     ^^^^^^^^ cannot assign
 
 error: aborting due to 12 previous errors
 
diff --git a/src/test/ui/did_you_mean/issue-40823.nll.stderr b/src/test/ui/did_you_mean/issue-40823.nll.stderr
@@ -1,8 +1,10 @@
 error[E0596]: cannot borrow immutable item `*buf` as mutable
   --> $DIR/issue-40823.rs:13:5
    |
+LL |     let mut buf = &[1, 2, 3, 4];
+   |                   ------------- help: consider changing this to be a mutable reference: `&mut [1, 2, 3, 4]`
 LL |     buf.iter_mut(); //~ ERROR cannot borrow immutable borrowed content
-   |     ^^^ cannot borrow as mutable
+   |     ^^^ `buf` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/error-codes/E0389.nll.stderr b/src/test/ui/error-codes/E0389.nll.stderr
@@ -1,4 +1,4 @@
-error[E0594]: cannot assign to data in a `&` reference
+error[E0594]: cannot assign to `fancy_ref.num` which is behind a `&` reference
   --> $DIR/E0389.rs:18:5
    |
 LL |     let fancy_ref = &(&mut fancy);
diff --git a/src/test/ui/issue-36400.nll.stderr b/src/test/ui/issue-36400.nll.stderr
@@ -1,10 +1,10 @@
 error[E0596]: cannot borrow immutable item `*x` as mutable
   --> $DIR/issue-36400.rs:15:7
    |
+LL |     let x = Box::new(3);
+   |         - help: consider changing this to be mutable: `mut x`
 LL |     f(&mut *x); //~ ERROR cannot borrow immutable
    |       ^^^^^^^ cannot borrow as mutable
-   |
-   = note: the value which is causing this path not to be mutable is...: `x`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lifetime-errors/ex3-both-anon-regions-using-fn-items.nll.stderr b/src/test/ui/lifetime-errors/ex3-both-anon-regions-using-fn-items.nll.stderr
@@ -15,6 +15,8 @@ LL |   y.push(z); //~ ERROR lifetime mismatch
 error[E0596]: cannot borrow immutable item `y` as mutable
   --> $DIR/ex3-both-anon-regions-using-fn-items.rs:11:3
    |
+LL | fn foo(x:fn(&u8, &u8), y: Vec<&u8>, z: &u8) {
+   |                        - help: consider changing this to be mutable: `mut y`
 LL |   y.push(z); //~ ERROR lifetime mismatch
    |   ^ cannot borrow as mutable
 
diff --git a/src/test/ui/lifetime-errors/ex3-both-anon-regions-using-trait-objects.nll.stderr b/src/test/ui/lifetime-errors/ex3-both-anon-regions-using-trait-objects.nll.stderr
@@ -15,6 +15,8 @@ LL |   y.push(z); //~ ERROR lifetime mismatch
 error[E0596]: cannot borrow immutable item `y` as mutable
   --> $DIR/ex3-both-anon-regions-using-trait-objects.rs:11:3
    |
+LL | fn foo(x:Box<Fn(&u8, &u8)> , y: Vec<&u8>, z: &u8) {
+   |                              - help: consider changing this to be mutable: `mut y`
 LL |   y.push(z); //~ ERROR lifetime mismatch
    |   ^ cannot borrow as mutable
 
diff --git a/src/test/ui/macros/span-covering-argument-1.nll.stderr b/src/test/ui/macros/span-covering-argument-1.nll.stderr
@@ -1,6 +1,8 @@
 error[E0596]: cannot borrow immutable item `foo` as mutable
   --> $DIR/span-covering-argument-1.rs:15:14
    |
+LL |             let $s = 0;
+   |                 -- help: consider changing this to be mutable: `mut foo`
 LL |             *&mut $s = 0;
    |              ^^^^^^^ cannot borrow as mutable
 ...
diff --git a/src/test/ui/nll/issue-47388.stderr b/src/test/ui/nll/issue-47388.stderr
@@ -1,4 +1,4 @@
-error[E0594]: cannot assign to data in a `&` reference
+error[E0594]: cannot assign to `fancy_ref.num` which is behind a `&` reference
   --> $DIR/issue-47388.rs:18:5
    |
 LL |     let fancy_ref = &(&mut fancy);
diff --git a/src/test/ui/rfc-2005-default-binding-mode/enum.nll.stderr b/src/test/ui/rfc-2005-default-binding-mode/enum.nll.stderr
@@ -1,26 +1,20 @@
-error[E0594]: cannot assign to data in a `&` reference
+error[E0594]: cannot assign to `*x` which is behind a `&` reference
   --> $DIR/enum.rs:19:5
    |
-LL |     let Wrap(x) = &Wrap(3);
-   |              - help: consider changing this to be a mutable reference: `&mut`
 LL |     *x += 1; //~ ERROR cannot assign to immutable
-   |     ^^^^^^^
+   |     ^^^^^^^ cannot assign
 
-error[E0594]: cannot assign to data in a `&` reference
+error[E0594]: cannot assign to `*x` which is behind a `&` reference
   --> $DIR/enum.rs:23:9
    |
-LL |     if let Some(x) = &Some(3) {
-   |                 - help: consider changing this to be a mutable reference: `&mut`
 LL |         *x += 1; //~ ERROR cannot assign to immutable
-   |         ^^^^^^^
+   |         ^^^^^^^ cannot assign
 
-error[E0594]: cannot assign to data in a `&` reference
+error[E0594]: cannot assign to `*x` which is behind a `&` reference
   --> $DIR/enum.rs:29:9
    |
-LL |     while let Some(x) = &Some(3) {
-   |                    - help: consider changing this to be a mutable reference: `&mut`
 LL |         *x += 1; //~ ERROR cannot assign to immutable
-   |         ^^^^^^^
+   |         ^^^^^^^ cannot assign
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/rfc-2005-default-binding-mode/explicit-mut.nll.stderr b/src/test/ui/rfc-2005-default-binding-mode/explicit-mut.nll.stderr
@@ -1,26 +1,20 @@
-error[E0594]: cannot assign to data in a `&` reference
+error[E0594]: cannot assign to `*n` which is behind a `&` reference
   --> $DIR/explicit-mut.rs:17:13
    |
-LL |         Some(n) => {
-   |              - help: consider changing this to be a mutable reference: `&mut`
 LL |             *n += 1; //~ ERROR cannot assign to immutable
-   |             ^^^^^^^
+   |             ^^^^^^^ cannot assign
 
-error[E0594]: cannot assign to data in a `&` reference
+error[E0594]: cannot assign to `*n` which is behind a `&` reference
   --> $DIR/explicit-mut.rs:25:13
    |
-LL |         Some(n) => {
-   |              - help: consider changing this to be a mutable reference: `&mut`
 LL |             *n += 1; //~ ERROR cannot assign to immutable
-   |             ^^^^^^^
+   |             ^^^^^^^ cannot assign
 
-error[E0594]: cannot assign to data in a `&` reference
+error[E0594]: cannot assign to `*n` which is behind a `&` reference
   --> $DIR/explicit-mut.rs:33:13
    |
-LL |         Some(n) => {
-   |              - help: consider changing this to be a mutable reference: `&mut`
 LL |             *n += 1; //~ ERROR cannot assign to immutable
-   |             ^^^^^^^
+   |             ^^^^^^^ cannot assign
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/span/borrowck-borrow-overloaded-auto-deref-mut.nll.stderr b/src/test/ui/span/borrowck-borrow-overloaded-auto-deref-mut.nll.stderr
diff --git a/src/test/ui/span/borrowck-borrow-overloaded-deref-mut.nll.stderr b/src/test/ui/span/borrowck-borrow-overloaded-deref-mut.nll.stderr
diff --git a/src/test/ui/span/borrowck-call-is-borrow-issue-12224.nll.stderr b/src/test/ui/span/borrowck-call-is-borrow-issue-12224.nll.stderr
diff --git a/src/test/ui/span/borrowck-call-method-from-mut-aliasable.nll.stderr b/src/test/ui/span/borrowck-call-method-from-mut-aliasable.nll.stderr
diff --git a/src/test/ui/span/borrowck-fn-in-const-b.nll.stderr b/src/test/ui/span/borrowck-fn-in-const-b.nll.stderr
diff --git a/src/test/ui/span/borrowck-object-mutability.nll.stderr b/src/test/ui/span/borrowck-object-mutability.nll.stderr
diff --git a/src/test/ui/span/mut-arg-hint.nll.stderr b/src/test/ui/span/mut-arg-hint.nll.stderr
diff --git a/src/test/ui/suggestions/closure-immutable-outer-variable.nll.stderr b/src/test/ui/suggestions/closure-immutable-outer-variable.nll.stderr
diff --git a/src/test/ui/suggestions/fn-closure-mutable-capture.nll.stderr b/src/test/ui/suggestions/fn-closure-mutable-capture.nll.stderr
diff --git a/src/test/ui/trivial-bounds-inconsistent-copy-reborrow.nll.stderr b/src/test/ui/trivial-bounds-inconsistent-copy-reborrow.nll.stderr

Original file line number	Diff line number	Diff line change
`@@ -17,6 +17,9 @@ LL \| \| x; //~ value moved here`
`17`	`17`	error[E0596]: cannot borrow immutable item `y` as mutable
`18`	`18`	`--> $DIR/augmented-assignments.rs:30:5`
`19`	`19`	`\|`
	`20`	`+LL \| let y = Int(2);`
	`21`	+ \| - help: consider changing this to be mutable: `mut y`
	`22`	+LL \| //~^ consider changing this to `mut y`
`20`	`23`	LL \| y //~ error: cannot borrow immutable local variable `y` as mutable
`21`	`24`	`\| ^ cannot borrow as mutable`
`22`	`25`
Original file line number	Diff line number	Diff line change
`@@ -1,6 +1,8 @@`
`1`	`1`	error[E0596]: cannot borrow immutable item `b` as mutable
`2`	`2`	`--> $DIR/mut-borrow-of-mut-ref.rs:18:7`
`3`	`3`	`\|`
	`4`	`+LL \| fn f(b: &mut i32) {`
	`5`	+ \| - help: consider changing this to be mutable: `mut b`
`4`	`6`	`LL \| g(&mut b) //~ ERROR cannot borrow`
`5`	`7`	`\| ^^^^^^ cannot borrow as mutable`
`6`	`8`
Original file line number	Diff line number	Diff line change
`@@ -1,6 +1,9 @@`
`1`	`1`	error[E0596]: cannot borrow immutable item `x` as mutable
`2`	`2`	`--> $DIR/huge_multispan_highlight.rs:100:13`
`3`	`3`	`\|`
	`4`	`+LL \| let x = "foo";`
	`5`	+ \| - help: consider changing this to be mutable: `mut x`
	`6`	`+...`
`4`	`7`	`LL \| let y = &mut x; //~ ERROR cannot borrow`
`5`	`8`	`\| ^^^^^^ cannot borrow as mutable`
`6`	`9`
Original file line number	Diff line number	Diff line change
`@@ -7,6 +7,8 @@ LL \| (&mut self).bar(); //~ ERROR cannot borrow`
`7`	`7`	error[E0596]: cannot borrow immutable item `self` as mutable
`8`	`8`	`--> $DIR/issue-31424.rs:23:9`
`9`	`9`	`\|`
	`10`	`+LL \| fn bar(self: &mut Self) {`
	`11`	+ \| ---- help: consider changing this to be mutable: `mut self`
`10`	`12`	`LL \| (&mut self).bar(); //~ ERROR cannot borrow`
`11`	`13`	`\| ^^^^^^^^^^^ cannot borrow as mutable`
`12`	`14`