Update error format for E0373

src/librustc_borrowck/borrowck/mod.rs

@@ -942,9 +942,12 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                           but it borrows {}, \
                           which is owned by the current function",
                          cmt_path_or_string)
-            .span_note(capture_span,
+            .span_label(capture_span,
                        &format!("{} is borrowed here",
                                 cmt_path_or_string))
+            .span_label(err.span,
+                       &format!("may outlive borrowed value {}",
+                                cmt_path_or_string))
             .span_suggestion(err.span,
                              &format!("to force the closure to take ownership of {} \
                                        (and any other referenced variables), \

src/test/compile-fail/borrowck/borrowck-escaping-closure-error-1.rs

@@ -22,4 +22,6 @@ fn main() {
     let mut books = vec![1,2,3];
     spawn(|| books.push(4));
     //~^ ERROR E0373
+    //~| NOTE `books` is borrowed here
+    //~| NOTE may outlive borrowed value `books`
 }

src/test/compile-fail/borrowck/borrowck-escaping-closure-error-2.rs

@@ -20,6 +20,8 @@ fn foo<'a>(x: &'a i32) -> Box<FnMut()+'a> {
     let mut books = vec![1,2,3];
     Box::new(|| books.push(4))
     //~^ ERROR E0373
+    //~| NOTE `books` is borrowed here
+    //~| NOTE may outlive borrowed value `books`
 }
 
 fn main() { }

src/test/compile-fail/issue-4335.rs

@@ -14,7 +14,10 @@ fn f<'r, T>(v: &'r T) -> Box<FnMut() -> T + 'r> {
     // FIXME (#22405): Replace `Box::new` with `box` here when/if possible.
     id(Box::new(|| *v))
         //~^ ERROR E0373
-        //~| ERROR cannot move out of borrowed content
+        //~| NOTE `v` is borrowed here
+        //~| NOTE may outlive borrowed value `v`
+        //~| ERROR E0507
+        //~| NOTE cannot move out of borrowed content
 }
 
 fn main() {

src/test/compile-fail/region-borrow-params-issue-29793-small.rs

@@ -16,6 +16,10 @@
 
 fn escaping_borrow_of_closure_params_1() {
     let g = |x: usize, y:usize| {
+        //~^ NOTE reference must be valid for the scope of call-site for function
+        //~| NOTE ...but borrowed value is only valid for the scope of function body
+        //~| NOTE reference must be valid for the scope of call-site for function
+        //~| NOTE ...but borrowed value is only valid for the scope of function body
         let f = |t: bool| if t { x } else { y }; // (separate errors for `x` vs `y`)
         //~^ ERROR `x` does not live long enough
         //~| ERROR `y` does not live long enough
@@ -31,6 +35,10 @@ fn escaping_borrow_of_closure_params_1() {
 
 fn escaping_borrow_of_closure_params_2() {
     let g = |x: usize, y:usize| {
+        //~^ NOTE reference must be valid for the scope of call-site for function
+        //~| NOTE ...but borrowed value is only valid for the scope of function body
+        //~| NOTE reference must be valid for the scope of call-site for function
+        //~| NOTE ...but borrowed value is only valid for the scope of function body
         let f = |t: bool| if t { x } else { y }; // (separate errors for `x` vs `y`)
         //~^ ERROR `x` does not live long enough
         //~| ERROR `y` does not live long enough
@@ -64,7 +72,11 @@ fn escaping_borrow_of_fn_params_1() {
     fn g<'a>(x: usize, y:usize) -> Box<Fn(bool) -> usize + 'a> {
         let f = |t: bool| if t { x } else { y }; // (separate errors for `x` vs `y`)
         //~^ ERROR E0373
+        //~| NOTE `x` is borrowed here
+        //~| NOTE may outlive borrowed value `x`
         //~| ERROR E0373
+        //~| NOTE `y` is borrowed here
+        //~| NOTE may outlive borrowed value `y`
         return Box::new(f);
     };
 
@@ -75,7 +87,11 @@ fn escaping_borrow_of_fn_params_2() {
     fn g<'a>(x: usize, y:usize) -> Box<Fn(bool) -> usize + 'a> {
         let f = |t: bool| if t { x } else { y }; // (separate errors for `x` vs `y`)
         //~^ ERROR E0373
+        //~| NOTE `x` is borrowed here
+        //~| NOTE may outlive borrowed value `x`
         //~| ERROR E0373
+        //~| NOTE `y` is borrowed here
+        //~| NOTE may outlive borrowed value `y`
         Box::new(f)
     };
 
@@ -99,7 +115,11 @@ fn escaping_borrow_of_method_params_1() {
         fn g<'a>(&self, x: usize, y:usize) -> Box<Fn(bool) -> usize + 'a> {
             let f = |t: bool| if t { x } else { y }; // (separate errors for `x` vs `y`)
             //~^ ERROR E0373
+            //~| NOTE `x` is borrowed here
+            //~| NOTE may outlive borrowed value `x`
             //~| ERROR E0373
+            //~| NOTE `y` is borrowed here
+            //~| NOTE may outlive borrowed value `y`
             return Box::new(f);
         }
     }
@@ -113,7 +133,11 @@ fn escaping_borrow_of_method_params_2() {
         fn g<'a>(&self, x: usize, y:usize) -> Box<Fn(bool) -> usize + 'a> {
             let f = |t: bool| if t { x } else { y }; // (separate errors for `x` vs `y`)
             //~^ ERROR E0373
+            //~| NOTE `x` is borrowed here
+            //~| NOTE may outlive borrowed value `x`
             //~| ERROR E0373
+            //~| NOTE `y` is borrowed here
+            //~| NOTE may outlive borrowed value `y`
             Box::new(f)
         }
     }
@@ -141,7 +165,11 @@ fn escaping_borrow_of_trait_impl_params_1() {
         fn g<'a>(&self, x: usize, y:usize) -> Box<Fn(bool) -> usize + 'a> {
             let f = |t: bool| if t { x } else { y }; // (separate errors for `x` vs `y`)
             //~^ ERROR E0373
+            //~| NOTE `x` is borrowed here
+            //~| NOTE may outlive borrowed value `x`
             //~| ERROR E0373
+            //~| NOTE `y` is borrowed here
+            //~| NOTE may outlive borrowed value `y`
             return Box::new(f);
         }
     }
@@ -156,7 +184,11 @@ fn escaping_borrow_of_trait_impl_params_2() {
         fn g<'a>(&self, x: usize, y:usize) -> Box<Fn(bool) -> usize + 'a> {
             let f = |t: bool| if t { x } else { y }; // (separate errors for `x` vs `y`)
             //~^ ERROR E0373
+            //~| NOTE `x` is borrowed here
+            //~| NOTE may outlive borrowed value `x`
             //~| ERROR E0373
+            //~| NOTE `y` is borrowed here
+            //~| NOTE may outlive borrowed value `y`
             Box::new(f)
         }
     }
@@ -184,7 +216,11 @@ fn escaping_borrow_of_trait_default_params_1() {
         fn g<'a>(&self, x: usize, y:usize) -> Box<Fn(bool) -> usize + 'a> {
             let f = |t: bool| if t { x } else { y }; // (separate errors for `x` vs `y`)
             //~^ ERROR E0373
+            //~| NOTE `x` is borrowed here
+            //~| NOTE may outlive borrowed value `x`
             //~| ERROR E0373
+            //~| NOTE `y` is borrowed here
+            //~| NOTE may outlive borrowed value `y`
             return Box::new(f);
         }
     }
@@ -198,7 +234,11 @@ fn escaping_borrow_of_trait_default_params_2() {
         fn g<'a>(&self, x: usize, y:usize) -> Box<Fn(bool) -> usize + 'a> {
             let f = |t: bool| if t { x } else { y }; // (separate errors for `x` vs `y`)
             //~^ ERROR E0373
+            //~| NOTE `x` is borrowed here
+            //~| NOTE may outlive borrowed value `x`
             //~| ERROR E0373
+            //~| NOTE `y` is borrowed here
+            //~| NOTE may outlive borrowed value `y`
             Box::new(f)
         }
     }

src/test/compile-fail/regions-nested-fns-2.rs

@@ -13,8 +13,11 @@ fn ignore<F>(_f: F) where F: for<'z> FnOnce(&'z isize) -> &'z isize {}
 fn nested() {
     let y = 3;
     ignore(
-        |z| { //~ ERROR E0373
+        |z| {
+            //~^ ERROR E0373
+            //~| NOTE may outlive borrowed value `y`
             if false { &y } else { z }
+            //~^ NOTE `y` is borrowed here
         });
 }