Well-typed program rejected by the type-checker

[vbgl]

The following program is well-typed, yet, it is rejected by the pre-typing phase (since version 2022.04).

fn id(reg u64 x) -> reg u64 { return x; }

inline
fn test() -> reg u64 {
  reg u64 r;
  r = id(42);
  return r;
}