Merge multiple mutable borrows of immutable binding errors

Fix #53466.

6 files changed, 77 insertions, 38 deletions

diff --git a/src/test/ui/borrowck/many-mutable-borrows.rs b/src/test/ui/borrowck/many-mutable-borrows.rs
new file mode 100644
index 00000000000..3e6ea9d25d9
--- /dev/null
+++ b/src/test/ui/borrowck/many-mutable-borrows.rs
@@ -0,0 +1,18 @@
+fn main() {
+    let v = Vec::new(); //~ ERROR cannot borrow `v` as mutable, as it is not declared as mutable
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+    v.push(0);
+}
diff --git a/src/test/ui/borrowck/many-mutable-borrows.stderr b/src/test/ui/borrowck/many-mutable-borrows.stderr
new file mode 100644
index 00000000000..25755d94323
--- /dev/null
+++ b/src/test/ui/borrowck/many-mutable-borrows.stderr
@@ -0,0 +1,32 @@
+error[E0596]: cannot borrow `v` as mutable, as it is not declared as mutable
+  --> $DIR/many-mutable-borrows.rs:2:9
+   |
+LL |     let v = Vec::new();
+   |         ^
+   |         |
+   |         not mutable
+   |         help: consider changing this to be mutable: `mut v`
+LL |     v.push(0);
+   |     --------- cannot borrow as mutable
+LL |     v.push(0);
+   |     --------- cannot borrow as mutable
+LL |     v.push(0);
+   |     --------- cannot borrow as mutable
+LL |     v.push(0);
+   |     --------- cannot borrow as mutable
+LL |     v.push(0);
+   |     --------- cannot borrow as mutable
+LL |     v.push(0);
+   |     --------- cannot borrow as mutable
+LL |     v.push(0);
+   |     --------- cannot borrow as mutable
+LL |     v.push(0);
+   |     --------- cannot borrow as mutable
+LL |     v.push(0);
+   |     --------- cannot borrow as mutable
+   |
+   = note: ...and 5 other attempted mutable borrows
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0596`.
diff --git a/src/test/ui/borrowck/mut-borrow-of-mut-ref.rs b/src/test/ui/borrowck/mut-borrow-of-mut-ref.rs
index 7cdb16b282d..477a2aa48d5 100644
--- a/src/test/ui/borrowck/mut-borrow-of-mut-ref.rs
+++ b/src/test/ui/borrowck/mut-borrow-of-mut-ref.rs
@@ -2,15 +2,14 @@
 #![crate_type = "rlib"]
 
 pub fn f(b: &mut i32) {
-    //~^ NOTE the binding is already a mutable borrow
+    //~^ ERROR cannot borrow
+    //~| NOTE not mutable
     //~| NOTE the binding is already a mutable borrow
     h(&mut b);
-    //~^ ERROR cannot borrow
-    //~| NOTE cannot borrow as mutable
+    //~^ NOTE cannot borrow as mutable
     //~| HELP try removing `&mut` here
     g(&mut &mut b);
-    //~^ ERROR cannot borrow
-    //~| NOTE cannot borrow as mutable
+    //~^ NOTE cannot borrow as mutable
     //~| HELP try removing `&mut` here
 }
 
diff --git a/src/test/ui/borrowck/mut-borrow-of-mut-ref.stderr b/src/test/ui/borrowck/mut-borrow-of-mut-ref.stderr
index 7782047574c..c6f75b1c0d0 100644
--- a/src/test/ui/borrowck/mut-borrow-of-mut-ref.stderr
+++ b/src/test/ui/borrowck/mut-borrow-of-mut-ref.stderr
@@ -1,8 +1,14 @@
 error[E0596]: cannot borrow `b` as mutable, as it is not declared as mutable
-  --> $DIR/mut-borrow-of-mut-ref.rs:7:7
+  --> $DIR/mut-borrow-of-mut-ref.rs:4:10
    |
+LL | pub fn f(b: &mut i32) {
+   |          ^ not mutable
+...
 LL |     h(&mut b);
-   |       ^^^^^^ cannot borrow as mutable
+   |       ------ cannot borrow as mutable
+...
+LL |     g(&mut &mut b);
+   |            ------ cannot borrow as mutable
    |
 note: the binding is already a mutable borrow
   --> $DIR/mut-borrow-of-mut-ref.rs:4:13
@@ -14,18 +20,6 @@ help: try removing `&mut` here
 LL -     h(&mut b);
 LL +     h(b);
    |
-
-error[E0596]: cannot borrow `b` as mutable, as it is not declared as mutable
-  --> $DIR/mut-borrow-of-mut-ref.rs:11:12
-   |
-LL |     g(&mut &mut b);
-   |            ^^^^^^ cannot borrow as mutable
-   |
-note: the binding is already a mutable borrow
-  --> $DIR/mut-borrow-of-mut-ref.rs:4:13
-   |
-LL | pub fn f(b: &mut i32) {
-   |             ^^^^^^^^
 help: try removing `&mut` here
    |
 LL -     g(&mut &mut b);
@@ -33,13 +27,13 @@ LL +     g(&mut b);
    |
 
 error[E0596]: cannot borrow `b` as mutable, as it is not declared as mutable
-  --> $DIR/mut-borrow-of-mut-ref.rs:18:12
+  --> $DIR/mut-borrow-of-mut-ref.rs:17:12
    |
 LL |     h(&mut &mut b);
    |            ^^^^^^ cannot borrow as mutable
    |
 note: the binding is already a mutable borrow
-  --> $DIR/mut-borrow-of-mut-ref.rs:17:13
+  --> $DIR/mut-borrow-of-mut-ref.rs:16:13
    |
 LL | pub fn g(b: &mut i32) {
    |             ^^^^^^^^
@@ -50,7 +44,7 @@ LL +     h(&mut b);
    |
 
 error[E0596]: cannot borrow `f` as mutable, as it is not declared as mutable
-  --> $DIR/mut-borrow-of-mut-ref.rs:35:5
+  --> $DIR/mut-borrow-of-mut-ref.rs:34:5
    |
 LL |     f.bar();
    |     ^^^^^^^ cannot borrow as mutable
@@ -60,6 +54,6 @@ help: consider making the binding mutable
 LL | pub fn baz(mut f: &mut String) {
    |            +++
 
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0596`.
diff --git a/src/test/ui/borrowck/mutability-errors.rs b/src/test/ui/borrowck/mutability-errors.rs
index 5be0df13761..82116425f06 100644
--- a/src/test/ui/borrowck/mutability-errors.rs
+++ b/src/test/ui/borrowck/mutability-errors.rs
@@ -50,9 +50,9 @@ fn ref_closure(mut x: (i32,)) {
     });
 }
 
-fn imm_local(x: (i32,)) {
-    &mut x; //~ ERROR
-    &mut x.0; //~ ERROR
+fn imm_local(x: (i32,)) { //~ ERROR
+    &mut x;
+    &mut x.0;
 }
 
 fn imm_capture(x: (i32,)) {
diff --git a/src/test/ui/borrowck/mutability-errors.stderr b/src/test/ui/borrowck/mutability-errors.stderr
index 7a00ace3bb2..5da8e60db75 100644
--- a/src/test/ui/borrowck/mutability-errors.stderr
+++ b/src/test/ui/borrowck/mutability-errors.stderr
@@ -245,21 +245,17 @@ LL |         &mut x.0;
    |         ^^^^^^^^ cannot borrow as mutable
 
 error[E0596]: cannot borrow `x` as mutable, as it is not declared as mutable
-  --> $DIR/mutability-errors.rs:54:5
+  --> $DIR/mutability-errors.rs:53:14
    |
 LL | fn imm_local(x: (i32,)) {
-   |              - help: consider changing this to be mutable: `mut x`
-LL |     &mut x;
-   |     ^^^^^^ cannot borrow as mutable
-
-error[E0596]: cannot borrow `x.0` as mutable, as `x` is not declared as mutable
-  --> $DIR/mutability-errors.rs:55:5
-   |
-LL | fn imm_local(x: (i32,)) {
-   |              - help: consider changing this to be mutable: `mut x`
+   |              ^
+   |              |
+   |              not mutable
+   |              help: consider changing this to be mutable: `mut x`
 LL |     &mut x;
+   |     ------ cannot borrow as mutable
 LL |     &mut x.0;
-   |     ^^^^^^^^ cannot borrow as mutable
+   |     -------- cannot borrow as mutable
 
 error[E0594]: cannot assign to `x`, as it is not declared as mutable
   --> $DIR/mutability-errors.rs:60:9
@@ -357,7 +353,7 @@ error[E0596]: cannot borrow `X.0` as mutable, as `X` is an immutable static item
 LL |     &mut X.0;
    |     ^^^^^^^^ cannot borrow as mutable
 
-error: aborting due to 38 previous errors
+error: aborting due to 37 previous errors
 
 Some errors have detailed explanations: E0594, E0596.
 For more information about an error, try `rustc --explain E0594`.