Zero-cost asynchronous programming in Rust
This report presents the forensic synthetic code analysis of rust-lang/futures-rs, a Rust project with 5,878 GitHub stars. SynthScan v2.0 examined 48,224 lines of code across 342 source files, recording 481 pattern matches distributed across 4 syntactic categories. The overall adjusted score of 9.2 places this repository in the Low AI signal band.
The scanner applied 160+ deterministic lexical heuristics, multi-line block detectors, abstract syntax tree depth profilers, and a cross-file Jaccard similarity matrix to construct a statistically normalised synthetic code estimate. All matches are individually weighted by severity coefficient and contextual multiplier before summation, and the resulting headline score is temporally discounted to account for the repository's development history relative to the commercial emergence of large language model coding tooling (November 2022 onward).
Longitudinal tracking requires multiple scan runs. Once this repository is re-scanned after new commits land, this chart will visualise how the synthetic code signal evolves over time — enabling you to detect whether AI authorship is growing, stabilising, or being actively corrected by human engineers.
Classifies detected patterns by their diagnostic confidence and structural impact. CRITICAL patterns (coefficient 10) represent definitive synthetic signatures — hallucinated imports, explicit LLM attribution metadata — virtually never produced by human authors. HIGH (5) indicates strong structural tells such as cross-file repetition or cross-linguistic idioms. MEDIUM (2) covers recognisable conversational padding and AI-specific vocabulary. LOW (1) captures subtle indicators like tautological comments and generic boilerplate that require density to carry independent signal.
This horizontal bar chart decomposes the repository's raw synthetic code score by top-level directory, allowing you to pinpoint precisely which modules or components carry the highest AI authorship density. Directories with disproportionately high scores relative to their size warrant targeted manual review: concentrated AI signatures often trace back to mass-generated configuration layers, auto-ported test suites, LLM-scaffolded boilerplate classes, or entire subsystems authored under heavy copilot assistance. Use this view to prioritise your human code-review effort.
The scanner identified 481 distinct pattern matches across 4 syntactic categories. Each entry below represents a discrete location in the source code where the engine recorded a statistically significant AI authorship indicator. Expand any category row to inspect the individual file paths, line numbers, code snippets, and the lexical context (CODE, COMMENT, or STRING) in which each match was detected.
Reading the findings table: The Severity column indicates the diagnostic confidence level (CRITICAL / HIGH / MEDIUM / LOW). The Context column identifies whether the match occurred inside executable code, an inline comment, or a string literal — comment-context matches receive a ×1.5 weight because LLMs systematically over-annotate. The ⚡ bolt icon marks clustered matches: three or more patterns within a 10-line window, each receiving an additional ×1.5 density multiplier as dense clusters constitute far stronger evidence of synthetic authorship than isolated hits.
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | futures-task/src/future_obj.rs | 121 | impl<T> Future for FutureObj<'_, T> { | COMMENT |
| LOW | futures-task/src/future_obj.rs | 141 | /// Convert an owned instance into a (conceptually owned) fat pointer. | COMMENT |
| LOW | futures-task/src/lib.rs | 21 | #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))] | COMMENT |
| LOW | futures-task/src/noop_waker.rs | 21 | /// # Examples | COMMENT |
| LOW | futures-task/src/spawn.rs | 1 | use crate::{FutureObj, LocalFutureObj}; | COMMENT |
| LOW | futures-task/src/spawn.rs | 21 | /// Likewise, an `Err` return means that `spawn` is likely, but | COMMENT |
| LOW | futures-task/src/arc_wake.rs | 1 | use alloc::sync::Arc; | COMMENT |
| LOW | futures-task/src/arc_wake.rs | 21 | /// Indicates that the associated task is ready to make progress and should | COMMENT |
| LOW | futures-task/src/arc_wake.rs | 41 | /// Executors generally maintain a queue of "ready" tasks; `wake_by_ref` should place | COMMENT |
| LOW | futures/tests/no-std/src/lib.rs | 1 | #![cfg(nightly)] | COMMENT |
| LOW | futures/src/lib.rs | 1 | //! Abstractions for asynchronous programming. | COMMENT |
| LOW | futures/src/lib.rs | 21 | //! streams and sinks, and then spawned as independent tasks that are run to | COMMENT |
| LOW | futures/src/lib.rs | 41 | //! let fut_values = async { | COMMENT |
| LOW | futures/src/lib.rs | 61 | //! let fut_values = rx | COMMENT |
| LOW | futures/src/lib.rs | 121 | pub use futures_core::ready; // Readiness propagation | COMMENT |
| LOW | futures/src/lib.rs | 141 | pub use futures_util::lock; | COMMENT |
| LOW | futures/src/lib.rs | 161 | //! | COMMENT |
| LOW | futures/src/lib.rs | 181 | //! little work between I/O operations. | COMMENT |
| LOW | futures/src/lib.rs | 221 | //! almost always want to import its entire contents, but unlike the | COMMENT |
| LOW | futures-channel/tests/oneshot.rs | 121 | } | COMMENT |
| LOW | futures-channel/tests/oneshot.rs | 141 | // | COMMENT |
| LOW | futures-channel/tests/oneshot.rs | 161 | // // need to implement a timeout for the test, as it would hang | COMMENT |
| LOW | futures-channel/tests/oneshot.rs | 181 | // // and wait for the spawned future to release its resources | COMMENT |
| LOW | futures-channel/tests/oneshot.rs | 201 | // use futures::future::Either; | COMMENT |
| LOW | futures-channel/tests/oneshot.rs | 221 | // } | COMMENT |
| LOW | futures-channel/tests/oneshot.rs | 241 | // rx.forget(); | COMMENT |
| LOW | futures-channel/tests/mpsc.rs | 141 | // let rx = mpsc::spawn(stream, &core, 1); | COMMENT |
| LOW | futures-channel/tests/mpsc.rs | 161 | // } | COMMENT |
| LOW | futures-channel/tests/mpsc.rs | 181 | // let stream = Dead{done: done_tx}; | COMMENT |
| LOW | futures-channel/src/oneshot.rs | 41 | /// For `Receiver`, if this is `true`, then it's guaranteed that `data` is | COMMENT |
| LOW | futures-channel/src/oneshot.rs | 61 | /// Both the `Receiver` and the `Sender` halves understand that if they | COMMENT |
| LOW | futures-channel/src/oneshot.rs | 81 | /// | COMMENT |
| LOW | futures-channel/src/oneshot.rs | 161 | } | COMMENT |
| LOW | futures-channel/src/oneshot.rs | 201 | // 2. The receiver is being dropped | COMMENT |
| LOW | futures-channel/src/oneshot.rs | 301 | // Indicate to the `Sender` that we're done, so any future calls to | COMMENT |
| LOW | futures-channel/src/oneshot.rs | 341 | pub fn send(self, t: T) -> Result<(), T> { | COMMENT |
| LOW | futures-channel/src/oneshot.rs | 361 | /// Creates a future that resolves when this `Sender`'s corresponding | COMMENT |
| LOW | futures-channel/src/lib.rs | 1 | //! Asynchronous channels. | COMMENT |
| LOW | futures-channel/src/lib.rs | 21 | ))] | COMMENT |
| LOW | futures-channel/src/mpsc/queue.rs | 21 | * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | COMMENT |
| LOW | futures-channel/src/mpsc/queue.rs | 101 | } | COMMENT |
| LOW | futures-channel/src/mpsc/queue.rs | 141 | /// This function is unsafe because only one thread can call it at a time. | COMMENT |
| LOW | futures-channel/src/mpsc/mod.rs | 1 | //! A multi-producer, single-consumer queue for sending values across | COMMENT |
| LOW | futures-channel/src/mpsc/mod.rs | 21 | //! | COMMENT |
| LOW | futures-channel/src/mpsc/mod.rs | 41 | // At the core, the channel uses an atomic FIFO queue for message passing. This | COMMENT |
| LOW | futures-channel/src/mpsc/mod.rs | 61 | // message that caused the sender to become parked is read out of the channel. | COMMENT |
| LOW | futures-channel/src/mpsc/mod.rs | 361 | self.is_parked = false; | COMMENT |
| LOW | futures-channel/src/mpsc/mod.rs | 721 | Err(TrySendError { err: SendError { kind: SendErrorKind::Disconnected }, val: msg }) | COMMENT |
| LOW | futures-channel/src/mpsc/mod.rs | 1021 | task.lock().unwrap().notify(); | COMMENT |
| LOW | futures-executor/src/thread_pool.rs | 21 | /// The thread pool multiplexes any number of tasks onto a fixed number of | COMMENT |
| LOW | futures-executor/src/thread_pool.rs | 81 | /// See documentation for the methods in | COMMENT |
| LOW | futures-executor/src/thread_pool.rs | 101 | pub fn spawn_obj_ok(&self, future: FutureObj<'static, ()>) { | COMMENT |
| LOW | futures-executor/src/thread_pool.rs | 221 | /// `my-pool-`, then threads in the pool will get names like `my-pool-1` etc. | COMMENT |
| LOW | futures-executor/src/lib.rs | 1 | //! Built-in executors and related tools. | COMMENT |
| LOW | futures-executor/src/lib.rs | 21 | //! directly. In the case of `!Send` futures, [`spawn_local_obj`] can be used | COMMENT |
| LOW | futures-executor/src/unpark_mutex.rs | 21 | // | COMMENT |
| LOW | futures-executor/src/enter.rs | 41 | /// use futures::executor::enter; | COMMENT |
| LOW | futures-executor/src/local_pool.rs | 21 | /// | COMMENT |
| LOW | futures-executor/src/local_pool.rs | 121 | /// Run all tasks in the pool to completion. | COMMENT |
| LOW | futures-executor/src/local_pool.rs | 141 | /// | COMMENT |
| 415 more matches not shown… | ||||
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | futures/tests/async_await_macros.rs | 343 | // This test may be a bit flaky. Feel free to adjust the margins as you see fit. | COMMENT |
| MEDIUM | futures-core/src/task/__internal/atomic_waker.rs | 42 | /// Here is a simple example providing a `Flag` that can be signalled manually | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | futures-channel/src/mpsc/mod.rs | 637 | /// # Return value | COMMENT |
| LOW | futures-channel/src/mpsc/mod.rs | 737 | /// # Return value | COMMENT |
| LOW | futures-core/src/stream.rs | 45 | /// # Return value | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | futures-util/src/io/line_writer.rs | 16 | /// Buffering is actually done using `BufWriter`. This class will leverage `BufWriter` | COMMENT |