error: expected string or byte string literal as input: unexpected end of input, expected literal
 --> $DIR/missing_parameter.rs:3:21
  |
3 | const _: [u8; 32] = ink::blake2x256!();
  |                     ^^^^^^^^^^^^^^^^^^
  |
  = note: this error originates in the macro `ink::blake2x256` (in Nightly builds, run with -Z macro-backtrace for more info)