Chez rejects duplicate lambda formals, so any (fn [_ _] ...) failed to compile
— including every macro expander, whose &form/&env slots both expand to _. The
analyzer now renames each earlier duplicate param to a fresh name (Clojure binds
the last occurrence, so the earlier ones are shadowed and unreferenceable). SCI
load 162 -> 186/218.
Re-port the SCI compatibility stress test to joltc: host/chez/run-sci.ss loads
borkdude/sci's own source (vendor/sci, re-vendored) through the spine and
requires its forms to compile+eval. Floor-gated at 160/218 forms (the tail is
genuine host gaps — set! on vars, some macro/def shapes); raise as they close.
Wired into 'make test' (skips if the submodule isn't checked out).
jolt-cf1q.6
