error[E0282]: type annotations needed for `Vec<_>`
 --> tests/fail_cases/empty_bec.rs:7:9
  |
7 |     let v = bec![];
  |         ^
  |
help: consider giving `v` an explicit type, where the placeholders `_` are specified
  |
7 |     let v: Vec<_> = bec![];
  |          ++++++++