test: RED owned-RawBuf drop-leak repro (refs #43)

raw_buf_owned_drop_balances_rc_stats + examples/raw_buf_drop_min.ail: a single owned 1-slot Int RawBuf, written once and read once. Prints 10 correctly but under AILANG_RC_STATS shows allocs=2 frees=1 live=1 — the slab leaks. Asserts stdout=="10" (green) and live==0 (RED until the owned-temp drop call is emitted). Root cause (verified, supersedes #42's disproven diagnosis). The leaked value is the anonymous owned temporary produced by RawBuf.set (own-ret, in-place: intercepts.rs emit_rawbuf_set_int does `ret ptr %b`, same slab as its input), then passed to RawBuf.get whose RawBuf param is `borrow`. After get borrows and returns an i64 the temp is dead, but no one drops it: codegen's only two scope-close drop emitters cover Term::Let binders (lib.rs:1785-1822) and Own fn-params (lib.rs:1426-1502); the general call lowerer emit_call (lib.rs:2552) splices args without inspecting per-arg own/borrow modes and emits no post-call drop for an owned arg landing in a borrow slot. Binder-independent, contra #42: the fully inline form with no `let` at all produces byte-identical leaking IR (no Term::Let exists, so the 1785 gate is never reached). The defect is the drop-CALL-site emission raw-buf.4 deferred to raw-buf.5; uniqueness.rs is not implicated.
2026-05-30 10:41:52 +02:00
parent 8ac8756682
commit 47efbdb5c0
2 changed files with 37 additions and 0 deletions
@@ -0,0 +1,9 @@
+(module raw_buf_drop_min
+  (fn main
+    (doc "Minimal RawBuf drop-leak reproducer (refs #42): a single owned 1-slot Int RawBuf, written once and read once, then dropped at the end of main. Prints 10. Under AILANG_RC_STATS the owned buffer's drop call must fire, so allocs are balanced by frees (live == 0). The leak is independent of binder names — the fully inline form (app RawBuf.get (app RawBuf.set (new RawBuf (con Int) 1) 0 10) 0) with no let-binding at all leaks identically.")
+    (type (fn-type (params) (ret (con Unit)) (effects IO)))
+    (params)
+    (body
+      (app print
+        (let buf (new RawBuf (con Int) 1)
+          (app RawBuf.get (app RawBuf.set buf 0 10) 0))))))