This maintains proposals for changes and user-visible enhancements to the Swift Programming Language.
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).
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.
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 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.
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | proposals/0336-distributed-actor-isolation.md | 301 | /// | COMMENT |
| LOW | proposals/0419-backtrace-api.md | 81 | /// | COMMENT |
| LOW | proposals/0419-backtrace-api.md | 101 | /// | COMMENT |
| LOW | proposals/0419-backtrace-api.md | 121 | /// | COMMENT |
| LOW | proposals/0419-backtrace-api.md | 181 | COMMENT | |
| LOW | proposals/0419-backtrace-api.md | 201 | /// | COMMENT |
| LOW | proposals/0419-backtrace-api.md | 241 | /// this off e.g. in Kubernetes so that pods restart promptly on crash. | COMMENT |
| LOW | proposals/0419-backtrace-api.md | 361 | /// True if this symbol represents a Swift runtime failure. | COMMENT |
| LOW | proposals/0453-vector.md | 261 | extension InlineArray where Element: ~Copyable { | COMMENT |
| LOW | proposals/0453-vector.md | 281 | /// an immutable borrow reference to the previously initialized element. The | COMMENT |
| LOW | proposals/0410-atomics.md | 201 | /// - An acquiring fence ties to any preceding atomic operation that | COMMENT |
| LOW | proposals/0410-atomics.md | 581 | ### Basic Atomic Operations | COMMENT |
| LOW | proposals/0410-atomics.md | 601 | ordering: AtomicStoreOrdering | COMMENT |
| LOW | proposals/0410-atomics.md | 621 | /// ``` | COMMENT |
| LOW | proposals/0410-atomics.md | 641 | ordering: AtomicUpdateOrdering | COMMENT |
| LOW | proposals/0410-atomics.md | 661 | /// will be used when the operation leaves the value intact. | COMMENT |
| LOW | proposals/0410-atomics.md | 681 | /// Perform an atomic weak compare and exchange operation on the current | COMMENT |
| LOW | proposals/0410-atomics.md | 701 | /// | COMMENT |
| LOW | proposals/0410-atomics.md | 721 | /// ``` | COMMENT |
| LOW | proposals/0410-atomics.md | 901 | /// the current value without updating it. | COMMENT |
| LOW | proposals/0405-string-validating-initializers.md | 61 | We want these new initializers to be performant. As such, their implementation should minimize the number of memory allo | COMMENT |
| LOW | proposals/0405-string-validating-initializers.md | 81 | /// let invalid = String(validating: invalidUTF16, as: UTF16.self) | COMMENT |
| LOW | proposals/0405-string-validating-initializers.md | 101 | /// The following example calls this initializer with the contents of two | COMMENT |
| LOW | proposals/0405-string-validating-initializers.md | 121 | validating codeUnits: some Sequence<Int8>, | COMMENT |
| LOW | proposals/0405-string-validating-initializers.md | 141 | /// validUTF8.withUnsafeBufferPointer { ptr in | COMMENT |
| LOW | proposals/0074-binary-search.md | 121 | /// Returns the range of elements equivalent to `element`, using | COMMENT |
| LOW | proposals/0074-binary-search.md | 141 | /// least partitioned by `element`. | COMMENT |
| LOW | proposals/0247-contiguous-strings.md | 41 | (For rationale on why StringProtocol was excluded, see “What about StringProtocol?” in Alternatives Considered) | COMMENT |
| LOW | proposals/0247-contiguous-strings.md | 61 | public mutating func makeContiguousUTF8() | COMMENT |
| LOW | proposals/0247-contiguous-strings.md | 81 | // Contiguous UTF-8 strings | COMMENT |
| LOW | proposals/0247-contiguous-strings.md | 101 | /// which will also speed up subsequent access. If this mutates the substring, | COMMENT |
| LOW | proposals/0247-contiguous-strings.md | 201 | /// Complexity: O(1) if `self` is contiguous UTF-8, otherwise O(n) | COMMENT |
| LOW | proposals/0259-approximately-equal.md | 81 | ```swift | COMMENT |
| LOW | proposals/0259-approximately-equal.md | 101 | /// Much of this advice is false, and most of the rest is technically | COMMENT |
| LOW | proposals/0259-approximately-equal.md | 121 | /// consult with a friendly numerical analyst. | COMMENT |
| LOW | proposals/0259-approximately-equal.md | 141 | guard self.isFinite && other.isFinite else { | COMMENT |
| LOW | proposals/0259-approximately-equal.md | 161 | /// subtractions, use a tolerance of `.ulpOfOne * n * scale`, where | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 281 | extension RawSpan { | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 301 | /// `offset` must be completely within the span. | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 341 | ``` | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 381 | ) where T: BitwiseCopyable | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 401 | /// Returns a value constructed from the raw memory at the specified offset. | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 421 | /// `offset` is not required to be aligned for `T`. | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 481 | as type: T.Type | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 501 | /// There must be at least `count * MemoryLayout<T>.stride` bytes | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 521 | /// - repeatedValue: The value to store as raw bytes. | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 581 | /// | COMMENT |
| LOW | proposals/0525-rawspan-safe-loading-api.md | 681 | COMMENT | |
| LOW | proposals/0445-string-index-printing.md | 141 | COMMENT | |
| LOW | proposals/0308-postfix-if-config-expressions.md | 221 | ### Nested `#if` blocks | COMMENT |
| LOW | …s/0424-custom-isolation-checking-for-serialexecutor.md | 61 | // ... | COMMENT |
| LOW | proposals/0138-unsaferawbufferpointer.md | 681 | ``` | COMMENT |
| LOW | proposals/0138-unsaferawbufferpointer.md | 701 | /// Generally, native Swift types that do not contain strong or | COMMENT |
| LOW | proposals/0138-unsaferawbufferpointer.md | 721 | /// // View a slice of memory at someBytes. Nothing is copied. | COMMENT |
| LOW | proposals/0138-unsaferawbufferpointer.md | 781 | /// Deallocate this memory allocated for `bytes` number of bytes. | COMMENT |
| LOW | proposals/0138-unsaferawbufferpointer.md | 801 | public func load<T>(fromByteOffset offset: Int = 0, as type: T.Type) -> T { | COMMENT |
| LOW | proposals/0138-unsaferawbufferpointer.md | 841 | /// Copies `count` bytes from `source` into memory at `self`. | COMMENT |
| LOW | proposals/0138-unsaferawbufferpointer.md | 921 | /// but it's indices will be rebased to zero. Given: | COMMENT |
| LOW | proposals/0138-unsaferawbufferpointer.md | 1081 | /// | COMMENT |
| LOW | proposals/0138-unsaferawbufferpointer.md | 1101 | ) rethrows -> R { | COMMENT |
| 632 more matches not shown… | ||||
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| HIGH | proposals/0382-expression-macros.md | 592 | * Remove the implementations of `#column`, as well as the implication that things like `#line` can be implemented with | COMMENT |
| HIGH | proposals/0356-swift-snippets.md | 395 | Another option was to support something like “[literate programming](http://www.literateprogramming.com/)” where source | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | proposals/0203-rename-sequence-elements-equal.md | 47 | > Contrived Example: Two Lorem Ipsum generators are the same generator (referentially equal, substitutable for the purpo | CODE |
| LOW⚡ | proposals/0182-newline-escape-in-strings.md | 28 | Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna | CODE |
| LOW⚡ | proposals/0182-newline-escape-in-strings.md | 28 | Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna | CODE |
| LOW⚡ | proposals/0182-newline-escape-in-strings.md | 33 | Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod \ | CODE |
| LOW⚡ | proposals/0182-newline-escape-in-strings.md | 33 | Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod \ | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | proposals/0160-objc-inference.md | 451 | ### Step 1: Address compiler warnings | COMMENT |
| LOW | proposals/0160-objc-inference.md | 507 | ### Step 2: Address (opt-in) runtime warnings | COMMENT |
| LOW | proposals/0160-objc-inference.md | 535 | ### Step 3: Migrate to Swift 4 | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | proposals/0344-distributed-actor-runtime.md | 393 | │── // actorSystem.actorReady(self) ────────────────▶│ Store a mapping (ID -> some DistributedActor) | CODE |
| MEDIUM | proposals/0344-distributed-actor-runtime.md | 397 | ◌ deinit ─ // actorSystem.resignID(self.id) ────────▶│ Remove (ID -> some DistributedActor) mapping | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | proposals/0235-add-result.md | 248 | /// print("Error retrieving the value: \(error)") | COMMENT |