error: expected `{`, found `}`
  --> $DIR/while-if-let-without-body.rs:11:1
   |
LL |       while if let Some(thing) = container.get(i) {
   |  _____-----_-
   | |     |
   | |     while parsing the body of this `while` expression
LL | |
LL | |
LL | |         println!("{:?}", thing);
LL | |         i += 1;
LL | |     }
   | |_____- this `while` condition successfully parsed
LL |   }
   |   ^ expected `{`

error: aborting due to 1 previous error