error[E0030]: lower range bound must be less than or equal to upper
  --> $DIR/E0030-teach.rs:15:9
   |
15 |         1000 ... 5 => {}
   |         ^^^^ lower bound larger than upper bound
   |
   = note: When matching against a range, the compiler verifies that the range is non-empty. Range patterns include both end-points, so this is equivalent to requiring the start of the range to be less than or equal to the end of the range.

error: aborting due to previous error