What problem does it solve? Native Jac binaries manage heap memory with reference counting by default, and developers hit cryptic E13xx/E14xx diagnostics, refcount churn, leaks, or fail when building zero-RC binaries. This Skill provides the operational knowledge to interpret those diagnostics, apply ownership annotations, use Region arenas, and verify RC-free builds. ## Core Features & Use Cases - Emit-time GC modes: Choose between --gc cycles (RC plus cycle collector), --gc rc (RC only), and --gc none (no retain/release call sites) when compiling with jac nacompile. - Ownership and borrow checking: Apply opt-in own, &/&mut, and imm annotations, resolve E1301-E1309 diagnostics, and use def drop for deterministic destruction. - Region arenas: Allocate objects inside in <handle> { } blocks for bulk reclamation, move own Region handles across flow boundaries, and respect E1307 boundary rules. - Zero-RC enforced builds: Run --enforce-nogc with --assert-no-rc, fix E1401-E1406 hard errors, and measure coverage with JAC_RC_STATS. - Use Case: A native binary leaks memory under load. Load this Skill to bisect with JAC_NO_GC=1, inspect JAC_RC_STATS output, then annotate hot paths with own/& or move allocations into a Region arena. ## Quick Start Ask the assistant to explain and fix the E1401 error reported when compiling your Jac module with jac nacompile --gc none --enforce-nogc.
