Strongly typed JSON library for Rust
This report presents the forensic synthetic code analysis of serde-rs/json, a Rust project with 5,611 GitHub stars. SynthScan v2.0 examined 24,021 lines of code across 77 source files, recording 191 pattern matches distributed across 2 syntactic categories. The overall adjusted score of 7.5 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 191 distinct pattern matches across 2 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 | Cargo.toml | 61 | # Make serde_json::Map use a representation which maintains insertion order. | COMMENT |
| LOW | Cargo.toml | 81 | arbitrary_precision = [] | COMMENT |
| LOW | src/number.rs | 161 | /// Represents the number as f64 if possible. Returns None otherwise. | COMMENT |
| LOW | src/number.rs | 221 | } | COMMENT |
| LOW | src/number.rs | 281 | COMMENT | |
| LOW | src/error.rs | 101 | pub fn is_data(&self) -> bool { | COMMENT |
| LOW | src/error.rs | 121 | /// use std::io::{self, ErrorKind, Read}; | COMMENT |
| LOW | src/error.rs | 141 | /// Err(error) => { | COMMENT |
| LOW | src/error.rs | 181 | /// | COMMENT |
| LOW | src/error.rs | 201 | /// } | COMMENT |
| LOW | src/lib.rs | 1 | //! # Serde JSON | COMMENT |
| LOW | src/lib.rs | 21 | //! There are three common ways that you might find yourself needing to work | COMMENT |
| LOW | src/lib.rs | 41 | //! representation. This data structure is [`serde_json::Value`][value]. | COMMENT |
| LOW | src/lib.rs | 61 | //! | COMMENT |
| LOW | src/lib.rs | 81 | //! println!("Please call {} at the number {}", v["name"], v["phones"][0]); | COMMENT |
| LOW | src/lib.rs | 101 | //! containing a JSON string and its JSON representation is `"John Doe"`. | COMMENT |
| LOW | src/lib.rs | 121 | //! use serde::{Deserialize, Serialize}; | COMMENT |
| LOW | src/lib.rs | 141 | //! }"#; | COMMENT |
| LOW | src/lib.rs | 161 | //! automatically interpret the input data as a `Person` and produce informative | COMMENT |
| LOW | src/lib.rs | 181 | //! | COMMENT |
| LOW | src/lib.rs | 201 | //! ``` | COMMENT |
| LOW | src/lib.rs | 221 | //! "name": full_name, | COMMENT |
| LOW | src/lib.rs | 241 | //! | COMMENT |
| LOW | src/lib.rs | 261 | //! | COMMENT |
| LOW | src/lib.rs | 281 | //! without the rest of the Rust standard library. Disable the default "std" | COMMENT |
| LOW | src/raw.rs | 21 | /// | COMMENT |
| LOW | src/raw.rs | 41 | /// #[derive(Deserialize)] | COMMENT |
| LOW | src/raw.rs | 61 | /// let input: Input = serde_json::from_str(input)?; | COMMENT |
| LOW | src/raw.rs | 81 | /// The typical usage of `RawValue` will be in the borrowed form: | COMMENT |
| LOW | src/raw.rs | 101 | /// | COMMENT |
| LOW | src/raw.rs | 181 | /// except that we avoid an allocation and memcpy if both of the following | COMMENT |
| LOW | src/raw.rs | 201 | /// | COMMENT |
| LOW | src/raw.rs | 221 | /// // SAFETY: `json` was produced by serde_json's own serializer, so it is | COMMENT |
| LOW | src/raw.rs | 241 | /// ``` | COMMENT |
| LOW | src/raw.rs | 281 | /// Convert a `T` into a boxed `RawValue`. | COMMENT |
| LOW | src/raw.rs | 301 | /// b: u32, | COMMENT |
| LOW | src/raw.rs | 321 | /// This conversion can fail if `T`'s implementation of `Serialize` decides to | COMMENT |
| LOW | src/ser.rs | 1681 | /// correctly formatted but unspecified numerical value. | COMMENT |
| LOW | src/ser.rs | 1701 | /// | COMMENT |
| LOW | src/ser.rs | 2181 | { | COMMENT |
| LOW | src/de.rs | 41 | impl<'de, R> Deserializer<R> | COMMENT |
| LOW | src/de.rs | 161 | StreamDeserializer { | COMMENT |
| LOW | src/de.rs | 181 | /// *This method is only available if serde_json is built with the | COMMENT |
| LOW | src/de.rs | 201 | /// carefully_drop_nested_arrays(value); | COMMENT |
| LOW | src/de.rs | 1561 | /// whether the bytes represent a valid UTF-8 string. | COMMENT |
| LOW | src/de.rs | 1581 | /// | COMMENT |
| LOW | src/de.rs | 1601 | /// | COMMENT |
| LOW | src/de.rs | 1621 | /// use serde_bytes::ByteBuf; | COMMENT |
| LOW | src/de.rs | 2341 | /// | COMMENT |
| LOW | src/de.rs | 2401 | /// let de = serde_json::Deserializer::from_slice(data); | COMMENT |
| LOW | src/de.rs | 2521 | /// | COMMENT |
| LOW | src/de.rs | 2541 | /// # Example | COMMENT |
| LOW | src/de.rs | 2561 | /// let file = File::open(path)?; | COMMENT |
| LOW | src/de.rs | 2581 | /// ``` | COMMENT |
| LOW | src/de.rs | 2601 | /// fn main() { | COMMENT |
| LOW | src/de.rs | 2621 | /// type. | COMMENT |
| LOW | src/de.rs | 2641 | /// fingerprint: String, | COMMENT |
| LOW | src/de.rs | 2661 | /// structure expected by `T`, for example if `T` is a struct type but the input | COMMENT |
| LOW | src/de.rs | 2681 | /// #[derive(Deserialize, Debug)] | COMMENT |
| LOW | src/de.rs | 2701 | /// | COMMENT |
| 114 more matches not shown… | ||||
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | README.md | 30 | "name": "John Doe", | CODE |
| LOW | README.md | 94 | "name": "John Doe", | CODE |
| LOW | README.md | 120 | the output looks like `Please call "John Doe" at the number "+44 1234567"`. The | CODE |
| LOW | README.md | 122 | string and its JSON representation is `"John Doe"`. Printing as a plain string | CODE |
| LOW | README.md | 162 | "name": "John Doe", | CODE |
| LOW | README.md | 222 | "name": "John Doe", | CODE |
| LOW | README.md | 252 | let full_name = "John Doe"; | CODE |
| LOW | src/lib.rs | 8 | //! "name": "John Doe", | COMMENT |
| LOW | src/lib.rs | 69 | //! "name": "John Doe", | COMMENT |
| LOW | src/lib.rs | 99 | //! above, the output looks like `Please call "John Doe" at the number "+44 | COMMENT |
| LOW | src/lib.rs | 101 | //! containing a JSON string and its JSON representation is `"John Doe"`. | COMMENT |
| LOW | src/lib.rs | 135 | //! "name": "John Doe", | COMMENT |
| LOW | src/lib.rs | 188 | //! "name": "John Doe", | COMMENT |
| LOW | src/lib.rs | 216 | //! let full_name = "John Doe"; | COMMENT |
| LOW | src/value/mod.rs | 14 | //! "name": "John Doe", | COMMENT |
| LOW | src/value/mod.rs | 42 | //! let full_name = "John Doe"; | COMMENT |
| LOW | src/value/mod.rs | 68 | //! "name": "John Doe", | COMMENT |