These three were the last eager transformers, blocked by jolt-r81: a self-
recursive lazy-seq in the overlay leaks its macro expansion under :compile? when
recursion goes through a top-level name or (fn name …) self-name. Rewriting the
recursion as letfn-bound (the form partition-by/mapcat/dedupe already use, which
compiles cleanly) sidesteps the bug. All three are now lazy in interpret,
compile, and self-host — completing Option A for every transformer.
interleave: canonical lazy cons-recursion (2-arity) + map/concat (n-arity).
reductions: letfn step accumulator. tree-seq: letfn walk + lazy mapcat.
Gate: conformance 246x3, lazy-infinite 40/40 (+interleave/reductions/tree-seq
infinite cases), fixpoint, self-host, specs+unit green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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