A protocol method call compiles to (protocol-dispatch proto method this rest) — a
runtime registry walk (type-tag -> proto -> method) on every call, ~19x a direct
call. When the inference proves the receiver (arg 0) is a known record type, the
call now resolves to a DIRECT method call at compile time, skipping the registry.
- defprotocol registers each method's var-key 'ns/method' -> [proto method] (a
ctx-capturing register-protocol-methods! emitted into the do-block); infer-unit!
feeds it to the inference via a box (like record-shapes).
- the record-ctor return type carries :type (the record tag) so the inference
knows the receiver type; the :else invoke case annotates a protocol call whose
arg0 has a known :type with :devirt-{type,proto,method}.
- emit-invoke resolves the impl via find-protocol-method at emit time and emits a
direct call to the embedded impl fn value. Unknown/polymorphic receivers (no
proven :type) fall back to the dispatch path unchanged.
Measured: removes the dispatch overhead (14.7s -> 9.3s on a 10M-call loop); the
remaining cost is the method body itself (non-inlined, unproven reads) — inlining
the resolved method is the follow-up (jolt-t6r) toward direct-call speed.
Sound under the closed-world assumption direct-linking already makes (the impl is
resolved + embedded at compile time). Adds devirt-test (subprocess: dispatched ==
devirtualized across polymorphic dispatch, unknown-receiver fallback, and
heterogeneous collections). Stalin's compile-call/callee-environment is the model.
