error: expected a pattern range bound, found an expression
  --> $DIR/pat-ranges-3.rs:4:16
   |
LL |     let 10 ..= 10 + 3 = 12;
   |                ^^^^^^ arbitrary expressions are not allowed in patterns

error: expected a pattern range bound, found an expression
  --> $DIR/pat-ranges-3.rs:7:9
   |
LL |     let 10 - 3 ..= 10 = 8;
   |         ^^^^^^ arbitrary expressions are not allowed in patterns

error: aborting due to 2 previous errors