defprotocol/defrecord/extend-type/extend-protocol/reify + the extend/proxy/
definterface stubs move to 30-macros (user-facing, not used by the compiler). They
emit Jolt's protocol/type special forms (protocol-dispatch/register-method/
make-reified/deftype).
The one subtlety: a protocol value is a :jolt/type-tagged struct, and the
interpreter can't tell an embedded opaque value from a tagged map literal being
constructed. So defprotocol builds it via a make-protocol fn call (exposed from
core) instead of an embedded literal — a fn result evaluates normally and even
compiles. reify emits a {kw (fn* ...)} map literal that make-reified evaluates
(build-eval-map yields a struct it can iterate, unlike a hash-map phm). defrecord
vecs its spliced field-let bindings (a lazy mapcat seq won't splice) and uses an
explicit fresh-sym for the map-> param (auto-gensym doesn't cross nested
syntax-quotes).
protocols-spec 21/21, conformance 228x3, fixpoint, clojure-test-suite 3930, full
suite green.