error[E0505]: cannot move out of `a` because it is borrowed
  --> $DIR/borrow-for-loop-head.rs:4:18
   |
LL |     for i in &a {
   |               - borrow of `a` occurs here
LL |         for j in a {
   |                  ^ move out of `a` occurs here

error[E0382]: use of moved value: `a`
  --> $DIR/borrow-for-loop-head.rs:4:18
   |
LL |         for j in a {
   |                  ^ value moved here in previous iteration of loop
   |
   = note: move occurs because `a` has type `std::vec::Vec<i32>`, which does not implement the `Copy` trait
help: consider borrowing this to avoid moving it into the for loop
   |
LL |         for j in &a {
   |                  ^^

error: aborting due to 2 previous errors

Some errors occurred: E0382, E0505.
For more information about an error, try `rustc --explain E0382`.