An enum OR-fold under `as` ((m.A|m.B) as u32) was never typed:
scruttype resolves IDENT/DOT only, and the post-order restamp then
re-derived the folded member literals as untyped_int. The unstamped
operand missed cgtypeassert's #27b enum-reinterpret gate and lowered
as a phantom tagged assert — unconditional exit 1 at runtime on the
wwstage leg. checkisas now types an N_BIN lhs and the N_BIN restamp
preserves an existing enum stamp. Graduates the #59.9 stattest pin.
Hojun-Cho
125f626697