error: expected one of: `u16`, `u32`, `i16`, `i32`
 --> $DIR/invalid_type_wch.rs:3:30
  |
3 | const INVALID_TYPE: &[f32] = wch!(f32, "oops");
  |                              ^^^^^^^^^^^^^^^^^
  |
  = note: this error originates in the macro `wch` (in Nightly builds, run with -Z macro-backtrace for more info)