Merge pull request #1152 from gurgalex/make_borrow_example_fail_for_2018

Fix borrow so it fails in 2018 edition Fixes #1141

src/scope/borrow.md

@@ -34,10 +34,12 @@ fn main() {
         let _ref_to_i32: &i32 = &boxed_i32;
 
         // Error!
-        // Can't destroy `boxed_i32` while the inner value is borrowed.
+        // Can't destroy `boxed_i32` while the inner value is borrowed later in scope.
         eat_box_i32(boxed_i32);
         // FIXME ^ Comment out this line
 
+        // Attempt to borrow `_ref_to_i32` after inner value is destroyed
+        borrow_i32(_ref_to_i32);
         // `_ref_to_i32` goes out of scope and is no longer borrowed.
     }