Repository Analysis

swiftlang/swift-evolution

This maintains proposals for changes and user-visible enhancements to the Swift Programming Language.

3.3 Likely human-written View on GitHub

Analysis Overview

This report presents the forensic synthetic code analysis of swiftlang/swift-evolution, a Markdown project with 15,857 GitHub stars. SynthScan v2.0 examined 202,485 lines of code across 588 source files, recording 705 pattern matches distributed across 6 syntactic categories. The overall adjusted score of 3.3 places this repository in the Likely human-written 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).

3.3
Adjusted Score
3.3
Raw Score
100%
Time Factor
2026-07-10
Last Push
15.9K
Stars
Markdown
Language
202.5K
Lines of Code
588
Files
705
Pattern Hits
2026-07-14
Scan Date
0.00
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

This chart maps the temporal evolution of the adjusted synthetic code score across successive scan runs. An upward trajectory indicates ongoing incorporation of AI-generated code or expanding LLM-assisted scaffolding; a stable or declining trajectory may reflect active human refactoring, code removal, or the adoption of stricter authorship policies. The dashed secondary line (right axis) independently tracks total raw pattern hit count, which can diverge from the normalised score when codebase size changes significantly between scans.

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 2MEDIUM 3LOW 700

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 705 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.

Over-Commented Block692 hits · 643 pts
SeverityFileLineSnippetContext
LOWproposals/0336-distributed-actor-isolation.md301/// COMMENT
LOWproposals/0419-backtrace-api.md81 ///COMMENT
LOWproposals/0419-backtrace-api.md101 ///COMMENT
LOWproposals/0419-backtrace-api.md121 ///COMMENT
LOWproposals/0419-backtrace-api.md181COMMENT
LOWproposals/0419-backtrace-api.md201 ///COMMENT
LOWproposals/0419-backtrace-api.md241 /// this off e.g. in Kubernetes so that pods restart promptly on crash.COMMENT
LOWproposals/0419-backtrace-api.md361 /// True if this symbol represents a Swift runtime failure.COMMENT
LOWproposals/0453-vector.md261extension InlineArray where Element: ~Copyable {COMMENT
LOWproposals/0453-vector.md281 /// an immutable borrow reference to the previously initialized element. TheCOMMENT
LOWproposals/0410-atomics.md201/// - An acquiring fence ties to any preceding atomic operation thatCOMMENT
LOWproposals/0410-atomics.md581### Basic Atomic OperationsCOMMENT
LOWproposals/0410-atomics.md601 ordering: AtomicStoreOrderingCOMMENT
LOWproposals/0410-atomics.md621 /// ```COMMENT
LOWproposals/0410-atomics.md641 ordering: AtomicUpdateOrderingCOMMENT
LOWproposals/0410-atomics.md661 /// will be used when the operation leaves the value intact.COMMENT
LOWproposals/0410-atomics.md681 /// Perform an atomic weak compare and exchange operation on the currentCOMMENT
LOWproposals/0410-atomics.md701 ///COMMENT
LOWproposals/0410-atomics.md721 /// ```COMMENT
LOWproposals/0410-atomics.md901 /// the current value without updating it.COMMENT
LOWproposals/0405-string-validating-initializers.md61We want these new initializers to be performant. As such, their implementation should minimize the number of memory alloCOMMENT
LOWproposals/0405-string-validating-initializers.md81 /// let invalid = String(validating: invalidUTF16, as: UTF16.self)COMMENT
LOWproposals/0405-string-validating-initializers.md101 /// The following example calls this initializer with the contents of twoCOMMENT
LOWproposals/0405-string-validating-initializers.md121 validating codeUnits: some Sequence<Int8>,COMMENT
LOWproposals/0405-string-validating-initializers.md141 /// validUTF8.withUnsafeBufferPointer { ptr inCOMMENT
LOWproposals/0074-binary-search.md121 /// Returns the range of elements equivalent to `element`, usingCOMMENT
LOWproposals/0074-binary-search.md141 /// least partitioned by `element`.COMMENT
LOWproposals/0247-contiguous-strings.md41(For rationale on why StringProtocol was excluded, see “What about StringProtocol?” in Alternatives Considered)COMMENT
LOWproposals/0247-contiguous-strings.md61 public mutating func makeContiguousUTF8()COMMENT
LOWproposals/0247-contiguous-strings.md81// Contiguous UTF-8 stringsCOMMENT
LOWproposals/0247-contiguous-strings.md101 /// which will also speed up subsequent access. If this mutates the substring,COMMENT
LOWproposals/0247-contiguous-strings.md201 /// Complexity: O(1) if `self` is contiguous UTF-8, otherwise O(n)COMMENT
LOWproposals/0259-approximately-equal.md81```swiftCOMMENT
LOWproposals/0259-approximately-equal.md101 /// Much of this advice is false, and most of the rest is technicallyCOMMENT
LOWproposals/0259-approximately-equal.md121 /// consult with a friendly numerical analyst.COMMENT
LOWproposals/0259-approximately-equal.md141 guard self.isFinite && other.isFinite else {COMMENT
LOWproposals/0259-approximately-equal.md161 /// subtractions, use a tolerance of `.ulpOfOne * n * scale`, whereCOMMENT
LOWproposals/0525-rawspan-safe-loading-api.md281extension RawSpan {COMMENT
LOWproposals/0525-rawspan-safe-loading-api.md301 /// `offset` must be completely within the span.COMMENT
LOWproposals/0525-rawspan-safe-loading-api.md341```COMMENT
LOWproposals/0525-rawspan-safe-loading-api.md381 ) where T: BitwiseCopyableCOMMENT
LOWproposals/0525-rawspan-safe-loading-api.md401 /// Returns a value constructed from the raw memory at the specified offset.COMMENT
LOWproposals/0525-rawspan-safe-loading-api.md421 /// `offset` is not required to be aligned for `T`.COMMENT
LOWproposals/0525-rawspan-safe-loading-api.md481 as type: T.TypeCOMMENT
LOWproposals/0525-rawspan-safe-loading-api.md501 /// There must be at least `count * MemoryLayout<T>.stride` bytesCOMMENT
LOWproposals/0525-rawspan-safe-loading-api.md521 /// - repeatedValue: The value to store as raw bytes.COMMENT
LOWproposals/0525-rawspan-safe-loading-api.md581 ///COMMENT
LOWproposals/0525-rawspan-safe-loading-api.md681COMMENT
LOWproposals/0445-string-index-printing.md141COMMENT
LOWproposals/0308-postfix-if-config-expressions.md221### Nested `#if` blocksCOMMENT
LOW…s/0424-custom-isolation-checking-for-serialexecutor.md61 // ...COMMENT
LOWproposals/0138-unsaferawbufferpointer.md681```COMMENT
LOWproposals/0138-unsaferawbufferpointer.md701/// Generally, native Swift types that do not contain strong orCOMMENT
LOWproposals/0138-unsaferawbufferpointer.md721/// // View a slice of memory at someBytes. Nothing is copied.COMMENT
LOWproposals/0138-unsaferawbufferpointer.md781 /// Deallocate this memory allocated for `bytes` number of bytes.COMMENT
LOWproposals/0138-unsaferawbufferpointer.md801 public func load<T>(fromByteOffset offset: Int = 0, as type: T.Type) -> T {COMMENT
LOWproposals/0138-unsaferawbufferpointer.md841 /// Copies `count` bytes from `source` into memory at `self`.COMMENT
LOWproposals/0138-unsaferawbufferpointer.md921 /// but it's indices will be rebased to zero. Given:COMMENT
LOWproposals/0138-unsaferawbufferpointer.md1081 ///COMMENT
LOWproposals/0138-unsaferawbufferpointer.md1101 ) rethrows -> R {COMMENT
632 more matches not shown…
AI Response Leakage2 hits · 12 pts
SeverityFileLineSnippetContext
HIGHproposals/0382-expression-macros.md592 * Remove the implementations of `#column`, as well as the implication that things like `#line` can be implemented withCOMMENT
HIGHproposals/0356-swift-snippets.md395Another option was to support something like “[literate programming](http://www.literateprogramming.com/)” where source CODE
Fake / Example Data5 hits · 7 pts
SeverityFileLineSnippetContext
LOWproposals/0203-rename-sequence-elements-equal.md47> Contrived Example: Two Lorem Ipsum generators are the same generator (referentially equal, substitutable for the purpoCODE
LOWproposals/0182-newline-escape-in-strings.md28 Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna CODE
LOWproposals/0182-newline-escape-in-strings.md28 Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna CODE
LOWproposals/0182-newline-escape-in-strings.md33 Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod \CODE
LOWproposals/0182-newline-escape-in-strings.md33 Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod \CODE
Structural Annotation Overuse3 hits · 4 pts
SeverityFileLineSnippetContext
LOWproposals/0160-objc-inference.md451### Step 1: Address compiler warningsCOMMENT
LOWproposals/0160-objc-inference.md507### Step 2: Address (opt-in) runtime warningsCOMMENT
LOWproposals/0160-objc-inference.md535### Step 3: Migrate to Swift 4COMMENT
Decorative Section Separators2 hits · 4 pts
SeverityFileLineSnippetContext
MEDIUMproposals/0344-distributed-actor-runtime.md393 │── // actorSystem.actorReady(self) ────────────────▶│ Store a mapping (ID -> some DistributedActor)CODE
MEDIUMproposals/0344-distributed-actor-runtime.md397 ◌ deinit ─ // actorSystem.resignID(self.id) ────────▶│ Remove (ID -> some DistributedActor) mappingCODE
Excessive Try-Catch Wrapping1 hit · 3 pts
SeverityFileLineSnippetContext
MEDIUMproposals/0235-add-result.md248 /// print("Error retrieving the value: \(error)")COMMENT