walk-free B0: honest needs_legacy_walk=false on the 20 inert STM32 models#515
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Batch B0 of the walk-free STM32 campaign (docs/walk_free_plan.md). Assert needs_legacy_walk()==false on the 20 STM32 model types whose tick() is a structural no-op in every state (pure register banks / stubs / lazy-read models), so they no longer force the per-cycle legacy walk. Each override verified against the model's tick path: none of these types override tick()/tick_elapsed()/on_event()/sync_to()/uses_scheduler() — they use the trait defaults and emit nothing from the walk. Flash is marked too: its H5 erase/bank-swap ops drain via requires_cycle_accurate/drain_pending_op per instruction, never the walk, so tick() is the default no-op for all layouts. stub (syscfg) already carries the override. Structures marked: GpioPort, Lptim, Rcc, Pwr, Flash, Rng, Crc, Dac, Dbgmcu, Fmc, Quadspi, UsbOtg, Sdmmc, Comp, Tsc, Nvic, Iwdg, Wwdg, Rtc, Sai. New unit test (bus::tick::walk_free_campaign) pins the campaign's remaining walk-forcing surface on the runtime invaders bus (from_config + configure_cortex_m, flag stripped): the exact Class-B set awaiting scheduler migration plus the core DWT, and asserts derive_walk_deletable() stays false. Zero behaviour change: Class B still forces the walk, so the invaders bus does not flip walk-deletable.
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Jul 18, 2026
walk-free B0: honest needs_legacy_walk=false on the 20 inert STM32 models
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Batch B0 of the walk-free campaign (plan: docs/walk-free-plan branch, PR #514). Mechanical, additive-only sweep:
needs_legacy_walk() = falseon the 20 STM32 models whose tick is verified structurally inert (trait-default no-op, no scheduler hooks): GpioPort, Lptim, Rcc, Pwr, Rng, Crc, Dac, Dbgmcu, Fmc, Quadspi, UsbOtg, Sdmmc, Comp, Tsc, Iwdg, Wwdg, Rtc, Sai, Nvic, and Flash (verified: H5 ops drain per-instruction via requires_cycle_accurate, not the walk — tick is no-op for all layouts).Two plan corrections found and encoded:
All lanes green: workspace lib, jit+event-scheduler lib (1840 passed), invaders e2e 5/5 both lanes incl. the interval and derived-vs-explicit differentials, clippy -D warnings both lanes, fmt.