The closed-world fixpoint (#226) flowed record types across fn boundaries; this
adds a numeric refinement so a hintless fn whose every call site passes a flonum
has its param unboxed to fl-ops, no ^double hint needed.
Lattice gains :double, a flonum refinement of :num: two doubles join to :double,
a double joined with anything else widens to :num — so a param is :double only
when every contributing value is a flonum, which is what makes the fl-op sound.
infer types a flonum literal and flonum arithmetic (+ - * / min max inc dec over
double/int-literal operands) as :double, and the fixpoint joins those across call
sites and return types like any other lattice value.
The bridge to the existing hint-directed pass is a synthetic [param :double]
nhint: wp-infer! stashes the :double params separately from the structural seeds,
and run-passes injects them as nhints before numeric/annotate, so the fl-op
emission and the exact->inexact entry coercion (a no-op on a proven flonum) apply
unchanged.
Sound subset only: :double, never :long — an untyped integer can be a bignum and
fx-ops would overflow/diverge from jolt's arbitrary precision. So an integer
caller leaves a param generic; an escaped fn (unknown callers) keeps :any.
run-numwp.ss gate: cross-fn :double propagation incl. through a flonum-returning
helper, the integer-caller and escape negatives, and the full run-passes path
emitting fl* + entry coercion. make test / shakesmoke green, selfhost holds, 0
new divergences.
