hs.4 surfaced a leak the heap-str-abi spec didn't account for:
heap-Str slabs handed back by int_to_str / float_to_str and
immediately printed via io/print_str leak at scope close under
--alloc=rc. RED tests at e2e.rs (commit 592d87b) pin it.
Brainstorm settled on naming the rule rather than working
around it: Term::Do.args[*] are walked in Borrow position by
uniqueness and linearity passes, symmetric to Term::Ctor.args[*]
being walked in Consume position. The kind itself carries the
ownership default — no per-op field on EffectOpSig.
The rule alone doesn't close the leak; two heap-Str-specific
shape fixes follow (int_to_str / float_to_str gain ret_mode: Own;
drop_symbol_for_binder's App arm gets a Str carve-out symmetric
to field_drop_call's existing one). DESIGN anchor + WhatsNew +
audit-close from hs.5 roll into this milestone.
Grounding-check PASS — all nine load-bearing assumptions
ratified against currently-green tests (with the two RED tests
ratifying the leak as the spec's premise).
Brummel
89eb9fdc41