The N_TFN arm stamped only size and return, so every fn tinfo carried
a nil param chain and typeeq judged any two same-return fn types
equal: tagged-union dedup collapsed (*fn(A) T | *fn(B) T) to a bare
8-byte pointer and match read the pointer word as a tag, falling
through every arm for a real second-variant value. Build the tparam
chain like cstage's N_TFN resolve (bare ... sets the FFI variadic
flag; a Hare T... param wraps to []T with a per-param variadic bit
that typeeq now compares, mirroring cstage type_eq). Graduates the
four r76_typeeq_fn pins; the DATABYTEID_DIVERGED ledger is empty.
Hojun-Cho
0b1cc5ef7c