Auto merge of #52948 - davidtwco:issue-52633-later-loop-iteration, r=pnkfelix

NLL: Better Diagnostic When "Later" means "A Future Loop Iteration"

Part of #52663.

r? @pnkfelix

src/test/ui/borrowck/mut-borrow-outside-loop.nll.stderr

@@ -17,7 +17,7 @@ LL |         let inner_second = &mut inner_void; //~ ERROR cannot borrow
    |                            ^^^^^^^^^^^^^^^ second mutable borrow occurs here
 LL |         inner_second.use_mut();
 LL |         inner_first.use_mut();
-   |         ----------- borrow later used here
+   |         ----------- borrow used here in later iteration of loop
 
 error: aborting due to 2 previous errors
 

src/test/ui/issue-52126-assign-op-invariance.nll.stderr

@@ -5,7 +5,7 @@ LL |         let v: Vec<&str> = line.split_whitespace().collect();
    |                            ^^^^ borrowed value does not live long enough
 LL |         //~^ ERROR `line` does not live long enough
 LL |         println!("accumulator before add_assign {:?}", acc.map);
-   |                                                        ------- borrow later used here
+   |                                                        ------- borrow used here in later iteration of loop
 ...
 LL |     }
    |     - `line` dropped here while still borrowed

src/test/ui/rfc-2005-default-binding-mode/borrowck-issue-49631.nll.stderr

@@ -7,7 +7,7 @@ LL |         foo.mutate();
    |         ^^^^^^^^^^^^ mutable borrow occurs here
 LL |         //~^ ERROR cannot borrow `foo` as mutable
 LL |         println!("foo={:?}", *string);
-   |                              ------- borrow later used here
+   |                              ------- borrow used here in later iteration of loop
 
 error: aborting due to previous error
 

src/test/ui/span/regions-escape-loop-via-variable.nll.stderr

@@ -2,7 +2,7 @@ error[E0597]: `x` does not live long enough
   --> $DIR/regions-escape-loop-via-variable.rs:21:13
    |
 LL |         let x = 1 + *p;
-   |                     -- borrow later used here
+   |                     -- borrow used here in later iteration of loop
 LL |         p = &x;
    |             ^^ borrowed value does not live long enough
 LL |     }

src/test/ui/span/regions-escape-loop-via-vec.nll.stderr

@@ -7,7 +7,7 @@ LL |     while x < 10 { //~ ERROR cannot use `x` because it was mutably borrowed
    |           ^ use of borrowed `x`
 LL |         let mut z = x; //~ ERROR cannot use `x` because it was mutably borrowed
 LL |         _y.push(&mut z);
-   |         -- borrow later used here
+   |         -- borrow used here in later iteration of loop
 
 error[E0503]: cannot use `x` because it was mutably borrowed
   --> $DIR/regions-escape-loop-via-vec.rs:16:21
@@ -18,7 +18,7 @@ LL |     while x < 10 { //~ ERROR cannot use `x` because it was mutably borrowed
 LL |         let mut z = x; //~ ERROR cannot use `x` because it was mutably borrowed
    |                     ^ use of borrowed `x`
 LL |         _y.push(&mut z);
-   |         -- borrow later used here
+   |         -- borrow used here in later iteration of loop
 
 error[E0597]: `z` does not live long enough
   --> $DIR/regions-escape-loop-via-vec.rs:17:17
@@ -26,7 +26,7 @@ error[E0597]: `z` does not live long enough
 LL |         _y.push(&mut z);
    |         --      ^^^^^^ borrowed value does not live long enough
    |         |
-   |         borrow later used here
+   |         borrow used here in later iteration of loop
 ...
 LL |     }
    |     - `z` dropped here while still borrowed
@@ -38,7 +38,7 @@ LL |     let mut _y = vec![&mut x];
    |                       ------ borrow of `x` occurs here
 ...
 LL |         _y.push(&mut z);
-   |         -- borrow later used here
+   |         -- borrow used here in later iteration of loop
 LL |         //~^ ERROR `z` does not live long enough
 LL |         x += 1; //~ ERROR cannot assign
    |         ^^^^^^ use of borrowed `x`