error[E0373]: gen block may outlive the current function, but it borrows `x`, which is owned by the current function
  --> $DIR/gen_block_move.rs:7:5
   |
LL | /     gen {
LL | |         yield 42;
LL | |         if x == "foo" { return }
LL | |         x.clear();
   | |         - `x` is borrowed here
LL | |         for x in 3..6 { yield x }
LL | |     }
   | |_____^ may outlive borrowed value `x`
   |
note: gen block is returned here
  --> $DIR/gen_block_move.rs:7:5
   |
LL | /     gen {
LL | |         yield 42;
LL | |         if x == "foo" { return }
LL | |         x.clear();
LL | |         for x in 3..6 { yield x }
LL | |     }
   | |_____^
help: to force the gen block to take ownership of `x` (and any other referenced variables), use the `move` keyword
   |
LL |     gen move {
   |         ++++

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0373`.