recovered type matching, which was broken in 8a765db7e0f8 (see also 8a765db7e0f8, 2db1d3d2ed54); NB: "match" operates on direct substitution without variable chasing, in contrast to "unify" (and Unify.matches!) which work on cascaded env;

more direct type equality;

reverted commit accident from 994fe0ba8335

less space-wasting serialization setup: highest cell of array has been unused so far

tuned outline;

tuned syntax -- separate tokens;