Repository Analysis

rust-lang/rustfmt

Format Rust code

8.3 Low AI signal View on GitHub

Analysis Overview

This report presents the forensic synthetic code analysis of rust-lang/rustfmt, a Rust project with 6,922 GitHub stars. SynthScan v2.0 examined 104,782 lines of code across 2023 source files, recording 549 pattern matches distributed across 6 syntactic categories. The overall adjusted score of 8.3 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).

8.3
Adjusted Score
8.3
Raw Score
100%
Time Factor
2026-08-01
Last Push
6.9K
Stars
Rust
Language
104.8K
Lines of Code
2.0K
Files
549
Pattern Hits
2026-08-02
Scan Date
0.01
HC Hit Rate

What These Metrics Mean

Adjusted Score
Primary synthetic code indicator. Raw score normalised per 1,000 lines of code and multiplied by the temporal discount factor. This is the definitive comparative metric — use it to rank repositories by AI authorship density.
Raw Score
The unmodified sum of all severity-weighted, context-multiplied pattern match scores before temporal discounting. Reflects the absolute signal strength independent of when the repository was last active.
Time Factor
The temporal discount multiplier (0–100%) applied to the raw score. Repositories last updated before ChatGPT's launch (Nov 2022) receive a 5% factor. Full signal is only assigned to repositories active in the post-adoption era (Jan 2024+).
Pattern Hits
Total count of individual pattern matches across all files and categories. A high hit count with a low score may indicate a very large codebase with isolated AI snippets; a low count with a high score indicates dense, concentrated AI signatures.
HC Hit Rate
High+Critical pattern hits per file, averaged across the repository. This orthogonal signal catches repositories where a few files are densely packed with high-severity AI tells — a strong indicator even when the normalised score appears moderate due to codebase size.
Lines of Code / Files
Total lines and files analysed. The scanner examines 94 file extensions. These denominators are used to normalise the score, enabling fair comparison between repositories of vastly different sizes.

Score History

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.

No multi-scan history yet — run the scanner again to build trend data.

Severity Breakdown

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.

CRITICAL 0HIGH 12MEDIUM 11LOW 526

Directory Score Breakdown

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.

Pattern Findings

The scanner identified 549 distinct pattern matches across 6 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.

Fake / Example Data241 hits · 459 pts
SeverityFileLineSnippetContext
LOWConfigurations.md438// Lorem ipsum dolor sit amet, consectetur adipiscing elit.COMMENT
LOWConfigurations.md438// Lorem ipsum dolor sit amet, consectetur adipiscing elit.COMMENT
LOWConfigurations.md443// Lorem ipsum dolor sit amet,COMMENT
LOWConfigurations.md443// Lorem ipsum dolor sit amet,COMMENT
LOWConfigurations.md3298// Lorem ipsum dolor sit amet, consectetur adipiscing elit,COMMENT
LOWConfigurations.md3298// Lorem ipsum dolor sit amet, consectetur adipiscing elit,COMMENT
LOWConfigurations.md3304// Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aCOMMENT
LOWConfigurations.md3304// Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aCOMMENT
LOWConfigurations.md3306// Information on the lorem ipsum can be found at the following url: https://en.wikipedia.org/wiki/Lorem_ipsum. Its textCOMMENT
LOWConfigurations.md3306// Information on the lorem ipsum can be found at the following url: https://en.wikipedia.org/wiki/Lorem_ipsum. Its textCOMMENT
LOWConfigurations.md3315// Lorem ipsum dolor sit amet, consectetur adipiscing elit,COMMENT
LOWConfigurations.md3315// Lorem ipsum dolor sit amet, consectetur adipiscing elit,COMMENT
LOWConfigurations.md3321// Lorem ipsum dolor sit amet, consectetur adipiscing elit,COMMENT
LOWConfigurations.md3321// Lorem ipsum dolor sit amet, consectetur adipiscing elit,COMMENT
LOWConfigurations.md3327// Information on the lorem ipsum can be found at the following url: https://en.wikipedia.org/wiki/Lorem_ipsum. Its textCOMMENT
LOWConfigurations.md3327// Information on the lorem ipsum can be found at the following url: https://en.wikipedia.org/wiki/Lorem_ipsum. Its textCOMMENT
LOWConfigurations.md1221 let lorem = "ipsum dolor sit amet consectetur adipiscing elit lorem ipsum dolor sit amet consectetur adipiscing";CODE
LOWConfigurations.md1221 let lorem = "ipsum dolor sit amet consectetur adipiscing elit lorem ipsum dolor sit amet consectetur adipiscing";CODE
LOWConfigurations.md1229 let lorem = "ipsum dolor sit amet consectetur adipiscing elit lorem ipsum dolor sit amet \CODE
LOWConfigurations.md1229 let lorem = "ipsum dolor sit amet consectetur adipiscing elit lorem ipsum dolor sit amet \CODE
LOWConfigurations.md2125// Lorem ipsum:COMMENT
LOWConfigurations.md2135// Lorem ipsum:COMMENT
LOWtests/target/comment4.rs11 /* Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec aCOMMENT
LOWtests/target/comment4.rs11 /* Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec aCOMMENT
LOWtests/target/comment4.rs16 * libero sed arcu vehicula ultricies a non tortor. Lorem ipsum dolor sitCOMMENT
LOWtests/target/struct_lits_visual_multiline.rs35 A { // Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sitCODE
LOWtests/target/struct_lits_visual_multiline.rs35 A { // Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sitCODE
LOWtests/target/comment5.rs5//@ Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec adiam lectus.COMMENT
LOWtests/target/comment5.rs5//@ Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec adiam lectus.COMMENT
LOWtests/target/comment5.rs12//@@@ Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec adiamCOMMENT
LOWtests/target/comment5.rs12//@@@ Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec adiamCOMMENT
LOWtests/target/comment.rs6 //! Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diamCOMMENT
LOWtests/target/comment.rs6 //! Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diamCOMMENT
LOWtests/target/comment.rs15 // Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec aCOMMENT
LOWtests/target/comment.rs15 // Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec aCOMMENT
LOWtests/target/comment.rs20 // libero sed arcu vehicula ultricies a non tortor. Lorem ipsum dolor sitCOMMENT
LOWtests/target/struct_tuple_visual.rs22 A(// Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sitCODE
LOWtests/target/struct_tuple_visual.rs22 A(// Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sitCODE
LOWtests/target/issue-4210-disabled.rs14/// | long val | Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et COMMENT
LOWtests/target/issue-4210-disabled.rs14/// | long val | Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et COMMENT
LOWtests/target/issue-4079.rs4 * Lorem ipsum dolor sit amet, consectetur adipiscing elit. In laciniaCOMMENT
LOWtests/target/issue-4079.rs4 * Lorem ipsum dolor sit amet, consectetur adipiscing elit. In laciniaCOMMENT
LOWtests/target/issue-4079.rs9/*! Lorem ipsum dolor sit amet, consectetur adipiscing elit. In laciniaCOMMENT
LOWtests/target/issue-4079.rs9/*! Lorem ipsum dolor sit amet, consectetur adipiscing elit. In laciniaCOMMENT
LOWtests/target/struct_lits_visual.rs35 A { // Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sitCODE
LOWtests/target/struct_lits_visual.rs35 A { // Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sitCODE
LOWtests/target/struct_lits.rs42 // Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sitCOMMENT
LOWtests/target/struct_lits.rs42 // Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sitCOMMENT
LOWtests/target/struct_lits_multiline.rs52 // Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sitCOMMENT
LOWtests/target/struct_lits_multiline.rs52 // Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sitCOMMENT
LOWtests/target/issue-4210.rs14/// | long val | Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et COMMENT
LOWtests/target/issue-4210.rs14/// | long val | Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et COMMENT
LOWtests/target/issue-4791/issue_4928.rs21/// Lorem ipsum dolor sit amet.COMMENT
LOWtests/target/issue-4791/issue_4928.rs21/// Lorem ipsum dolor sit amet.COMMENT
LOWtests/target/issue-4791/issue_4928.rs26 /// Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididuntCOMMENT
LOWtests/target/issue-4791/issue_4928.rs26 /// Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididuntCOMMENT
LOWtests/target/itemized-blocks/urls.rs19//! - Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Vestibulum semCOMMENT
LOWtests/target/itemized-blocks/urls.rs19//! - Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Vestibulum semCOMMENT
LOWtests/target/issue-4036/two.rs7 "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor \CODE
LOWtests/target/issue-4036/two.rs7 "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor \CODE
181 more matches not shown…
Over-Commented Block284 hits · 282 pts
SeverityFileLineSnippetContext
LOWtriagebot.toml81remove_labels = ["S-waiting-on-author"]COMMENT
LOWConfigurations.md1001- **Stable**: No (tracking issue: [#3348](https://github.com/rust-lang/rustfmt/issues/3348))COMMENT
LOWConfigurations.md1021fn add_one(x: i32) -> i32 {COMMENT
LOWConfigurations.md1801// Leading pipes are removed from this:COMMENT
LOWConfigurations.md1821 _ => {}COMMENT
LOWConfigurations.md3301// exercitation ullamco laboris nisi ut aliquip ex eaCOMMENT
LOWconfig_proc_macro/src/lib.rs21 #[cfg(feature = "debug-with-rustfmt")]COMMENT
LOWconfig_proc_macro/src/lib.rs41pub fn nightly_only_test(_args: TokenStream, input: TokenStream) -> TokenStream {COMMENT
LOWconfig_proc_macro/src/attrs.rs1//! This module provides utilities for handling attributes on variantsCOMMENT
LOWtests/target/comment_crlf_newline.rs1// rustfmt-normalize_comments: trueCOMMENT
LOWtests/target/issue-2346.rs1// rustfmt-normalize_comments: trueCOMMENT
LOWtests/target/issue-2197.rs1// rustfmt-max_width: 79COMMENT
LOWtests/target/markdown-comment.rs1// Preserve two trailing whitespaces in doc comment,COMMENT
LOWtests/target/soft-wrapping.rs1// rustfmt-wrap_comments: trueCOMMENT
LOWtests/target/issue-3787.rs1// rustfmt-wrap_comments: trueCOMMENT
LOWtests/target/unsafe_attributes.rs1// https://github.com/rust-lang/rust/issues/123757COMMENT
LOWtests/target/unsafe_attributes.rs21#![unsafe(simple::path::tt[a b c])]COMMENT
LOWtests/target/issue-2111.rs21 // ModelRequests,COMMENT
LOWtests/target/doc-comment-with-example.rs1// rustfmt-format_code_in_doc_comments: trueCOMMENT
LOWtests/target/issue-3751.rs1// rustfmt-format_code_in_doc_comments: trueCOMMENT
LOWtests/target/issue_4573.rs1// rustmft-version:TwoCOMMENT
LOWtests/target/mulit-file.rs1// Tests that where a single file is referred to in multiple places, we don'tCOMMENT
LOWtests/target/issue-4041.rs1// rustfmt-wrap_comments: trueCOMMENT
LOWtests/target/multiple.rs1// rustfmt-normalize_comments: trueCOMMENT
LOWtests/target/comment5.rs1// rustfmt-normalize_comments: trueCOMMENT
LOWtests/target/issue-2523.rs1// rustfmt-normalize_comments: trueCOMMENT
LOW…doc_attributes_should_not_imply_format_doc_comments.rs1// rustfmt-normalize_doc_attributes: trueCOMMENT
LOWtests/target/comment.rs1// rustfmt-normalize_comments: trueCOMMENT
LOWtests/target/comment.rs21 // amet, consectetur adipiscing elit. Aenean ut gravida lorem. Ut turpisCOMMENT
LOWtests/target/issue_5907.rs1// rustfmt-format_code_in_doc_comments: trueCOMMENT
LOWtests/target/issue-5136-3.rs1// rustfmt-file_lines: []COMMENT
LOWtests/target/issue-691.rs1// rustfmt-normalize_comments: trueCOMMENT
LOWtests/target/issue-3105.rs1// rustfmt-wrap_comments: trueCOMMENT
LOWtests/target/let_else_v2.rs21COMMENT
LOWtests/target/issue-3182.rs1// rustfmt-max_width: 79COMMENT
LOWtests/target/let_else.rs101COMMENT
LOWtests/target/let_else.rs121COMMENT
LOWtests/target/let_else.rs181 // Because the initializer expr is multi-lined the else is placed on it's own line.COMMENT
LOWtests/target/issue-4210-disabled.rs1// rustfmt-wrap_comments: falseCOMMENT
LOWtests/target/issue-5136-2.rs1 use std;COMMENT
LOWtests/target/issue-5030.rs1// rustfmt-imports_granularity: ItemCOMMENT
LOWtests/target/issue-5136-5.rs1// rustfmt-file_lines: []COMMENT
LOWtests/target/issue-3224.rs1// rustfmt-wrap_comments: trueCOMMENT
LOWtests/target/issue-5095.rs21COMMENT
LOWtests/target/issue-683.rs1// rustfmt-normalize_comments: trueCOMMENT
LOWtests/target/issue-2896.rs61 (item_a, (item_b, num_cooccurrences, row_sum_a, row_sum_b))COMMENT
LOWtests/target/issue_4057.rs1// rustfmt-format_code_in_doc_comments: trueCOMMENT
LOWtests/target/issue-2941.rs1// rustfmt-wrap_comments: trueCOMMENT
LOWtests/target/issue-2520.rs1// rustfmt-normalize_comments: trueCOMMENT
LOWtests/target/issue-5234.rs1// rustfmt-format_code_in_doc_comments: trueCOMMENT
LOWtests/target/issue-5234.rs21/// ```COMMENT
LOWtests/target/issue-5234.rs41 /// ```COMMENT
LOWtests/target/issue-3153.rs1// rustfmt-wrap_comments: trueCOMMENT
LOWtests/target/doc-of-generic-item.rs1// Non-doc pre-comment of FooCOMMENT
LOWtests/target/doc-of-generic-item.rs21 /// doc of 'aCOMMENT
LOWtests/target/markdown-comment-with-options.rs1// rustfmt-wrap_comments: trueCOMMENT
LOWtests/target/issue-2401.rs1// rustfmt-hard_tabs = trueCOMMENT
LOWtests/target/issue-5136-4.rs1// rustfmt-file_lines: []COMMENT
LOWtests/target/issue-447.rs1// rustfmt-normalize_comments: trueCOMMENT
LOWtests/target/normalize_multiline_doc_attribute.rs1// rustfmt-unstable: trueCOMMENT
224 more matches not shown…
Synthetic Comment Markers12 hits · 90 pts
SeverityFileLineSnippetContext
HIGHtests/target/itemized-blocks/no_wrap.rs54/// * `to` is the receiving (local) [`ActorId`], as requested by the remote theaterCOMMENT
HIGHtests/target/itemized-blocks/no_wrap.rs64/// * `to` is the receiving (local) [`ActorId`], as requested by the remote theaterCOMMENT
HIGHtests/target/itemized-blocks/no_wrap.rs78/// * `to` is the receiving (local) [`ActorId`], as requested by the remote theaterCOMMENT
HIGHtests/target/itemized-blocks/wrap.rs109/// as requested by the remote theaterCOMMENT
HIGHtests/target/itemized-blocks/wrap.rs127/// as requested by the remote theaterCOMMENT
HIGHtests/target/itemized-blocks/wrap.rs145/// as requested by the remote theaterCOMMENT
HIGHtests/source/itemized-blocks/no_wrap.rs54/// * `to` is the receiving (local) [`ActorId`], as requested by the remote theaterCOMMENT
HIGHtests/source/itemized-blocks/no_wrap.rs64/// * `to` is the receiving (local) [`ActorId`], as requested by the remote theaterCOMMENT
HIGHtests/source/itemized-blocks/no_wrap.rs78/// * `to` is the receiving (local) [`ActorId`], as requested by the remote theaterCOMMENT
HIGHtests/source/itemized-blocks/wrap.rs62/// * `to` is the receiving (local) [`ActorId`], as requested by the remote theaterCOMMENT
HIGHtests/source/itemized-blocks/wrap.rs72/// * `to` is the receiving (local) [`ActorId`], as requested by the remote theaterCOMMENT
HIGHtests/source/itemized-blocks/wrap.rs86/// * `to` is the receiving (local) [`ActorId`], as requested by the remote theaterCOMMENT
Decorative Section Separators8 hits · 24 pts
SeverityFileLineSnippetContext
MEDIUMtriagebot.toml4# ------------------------------------------------------------------------------COMMENT
MEDIUMtriagebot.toml6# ------------------------------------------------------------------------------COMMENT
MEDIUMtriagebot.toml23# ------------------------------------------------------------------------------COMMENT
MEDIUMtriagebot.toml25# ------------------------------------------------------------------------------COMMENT
MEDIUMtriagebot.toml63# ------------------------------------------------------------------------------COMMENT
MEDIUMtriagebot.toml65# ------------------------------------------------------------------------------COMMENT
MEDIUMtriagebot.toml100# ------------------------------------------------------------------------------COMMENT
MEDIUMtriagebot.toml102# ------------------------------------------------------------------------------COMMENT
AI Slop Vocabulary3 hits · 9 pts
SeverityFileLineSnippetContext
MEDIUM.github/workflows/integration.yml30 # Instead, leverage `continue-on-error`COMMENT
MEDIUMsrc/imports.rs1155 // Parse the path part of an import. This parser is not robust and is onlyCOMMENT
MEDIUMsrc/visitor.rs958 // N.B. This could be updated to utilize the version gates.COMMENT
Redundant / Tautological Comments1 hit · 2 pts
SeverityFileLineSnippetContext
LOW.github/workflows/test.yml101 # Check if all jobs that we depend on (in the needs array) were successful (or have been skipped).COMMENT