Brummel
1be6e49b4f
An owned heap ADT param threaded through a tail-recursive fn whose base-case arm neither forwards nor consumes it is never RC-dec'd, so it leaks one slab per recursion step. Series-free minimal repro (a plain `Box` ADT, no Series/RawBuf), so the pin guards the GENERAL memory-model invariant rather than the Series surface that first surfaced it (examples/series_sma.ail, live=8). The pin builds the fixture with --alloc=rc, runs it under AILANG_RC_STATS=1, and asserts live == 0 (allocs == frees). RED today: `allocs=6 frees=4 live=2`. The fixture passes the replacement ctor directly into the tail call (not let-bound) to isolate leg 1 — the owned-param drop omission — from the second, distinct leg the debugger found (a `let`-wrapped tail call also defeats the scrutinee-husk shallow-dec gate; that leg is what pushes box_ctrl to live=4 and series_sma to live=8, and gets its own pin once leg 1 is green). Cause (debugger, for the GREEN side): the fn-return Own-param dec in crates/ailang-codegen/src/lib.rs (~1444) is gated behind `!block_terminated`, so it fires only on the fall-through ret path; crates/ailang-codegen/src/match_lower.rs (~805) drops only pattern binders, never the fn's owned params. A tail-call-terminated match arm thus has no drop site for an owned param with consume_count==0 that is not forwarded into the tail call. refs #63