The Julia Programming Language
This report presents the forensic synthetic code analysis of JuliaLang/julia, a Julia project with 49,028 GitHub stars. SynthScan v2.0 examined 245,428 lines of code across 657 source files, recording 575 pattern matches distributed across 11 syntactic categories. The overall adjusted score of 2.8 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 575 distinct pattern matches across 11 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 | test/gcext/gcext.c | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | test/embedding/asan-embedding.c | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | test/trim/LibSimple/capplication.c | 1 | #include <stdio.h> | COMMENT |
| LOW | test/clangsa/StaticOrDeclaredTest.c | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | test/clangsa/StaticOrDeclaredTest.c | 21 | // FIXYAML-NOT: ReplacementText | COMMENT |
| LOW | test/clangsa/FirstDeclAnnotationsTest.c | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | test/clangsa/FirstDeclAnnotationsTest.c | 121 | void fda_ovr_bad(void) override; | COMMENT |
| LOW | test/clangsa/FirstDeclAnnotationsTest.h | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | cli/loader_exe.c | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | cli/loader_lib.c | 201 | #endif | COMMENT |
| LOW | cli/jl_exports.h | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | cli/list_strip_symbols.h | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | cli/loader.h | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | cli/loader.h | 21 | #endif | COMMENT |
| LOW | cli/loader.h | 41 | # define JL_DLLIMPORT __declspec(dllimport) __attribute__ ((visibility("default"))) | COMMENT |
| LOW | cli/dl-cache.h | 21 | #define FLAG_ANY -1 | COMMENT |
| LOW | cli/dl-cache.h | 41 | #define FLAG_MIPS64_LIBN64_NAN2008 0x0e00 | COMMENT |
| LOW | cli/dl-cache.h | 101 | COMMENT | |
| LOW | cli/loader_library_probe.c | 1 | #include "../src/support/platform.h" | COMMENT |
| LOW | cli/trampolines/common.h | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | cli/trampolines/common.h | 21 | #if defined(_WIN32) || defined(_WIN64) | COMMENT |
| LOW | cli/trampolines/common.h | 41 | #define SEH_START2() .seh_endprologue | COMMENT |
| LOW | cli/trampolines/common.h | 61 | // aarch64 on mac requires some special assembler syntax for both calculating memory | COMMENT |
| LOW | contrib/tsan/build.sh | 1 | #!/bin/bash | COMMENT |
| LOW | contrib/mac/framework/Julia.h | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | contrib/asan/build.sh | 1 | #!/bin/bash | COMMENT |
| LOW | deps/valgrind/valgrind.h | 121 | #undef PLAT_arm64_linux | COMMENT |
| LOW | deps/valgrind/valgrind.h | 141 | # define PLAT_amd64_linux 1 | COMMENT |
| LOW | deps/valgrind/valgrind.h | 6581 | #undef PLAT_ppc64le_linux | COMMENT |
| LOW | doc/src/manual/methods.md | 781 | # R = typeof(op(a[1], b[1])) | COMMENT |
| LOW | src/runtime_intrinsics.c | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | src/runtime_intrinsics.c | 261 | (defined(__clang__) && __clang_major__ > 14)) && \ | COMMENT |
| LOW | src/runtime_intrinsics.c | 281 | #define FLOAT16_RET_FROM_UINT16(x) return_in_xmm(x) | COMMENT |
| LOW | src/runtime_intrinsics.c | 361 | return float_to_bfloat(param); | COMMENT |
| LOW | src/runtime_intrinsics.c | 741 | COMMENT | |
| LOW | src/runtime_intrinsics.c | 1581 | #define and_op(a,b) a & b | COMMENT |
| LOW | src/ircode.c | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | src/ircode.c | 21 | #define TAG_DATATYPE 4 | COMMENT |
| LOW | src/ircode.c | 41 | #define TAG_SINGLETON 24 | COMMENT |
| LOW | src/ircode.c | 61 | #define TAG_LONG_EDGE 44 | COMMENT |
| LOW | src/signal-handling.c | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | src/signal-handling.c | 81 | // or in the GC safe region and must NOT allocate anything through the GC | COMMENT |
| LOW | src/signal-handling.c | 461 | #endif | COMMENT |
| LOW | src/signal-handling.c | 481 | case SIGFPE: return "Floating point exception"; | COMMENT |
| LOW | src/signal-handling.c | 501 | #ifdef SIGTERM | COMMENT |
| LOW | src/signal-handling.c | 521 | #endif | COMMENT |
| LOW | src/gc-interface.h | 21 | struct _jl_genericmemory_t; | COMMENT |
| LOW | src/gc-interface.h | 41 | int64_t freed; | COMMENT |
| LOW | src/gc-interface.h | 101 | } jl_gc_num_t; | COMMENT |
| LOW | src/gc-interface.h | 141 | JL_DLLEXPORT void jl_gc_set_max_memory(uint64_t max_mem); | COMMENT |
| LOW | src/gc-interface.h | 161 | COMMENT | |
| LOW | src/gc-interface.h | 181 | // (doesn't include the number of allocated bytes since then). | COMMENT |
| LOW | src/gc-interface.h | 201 | // Allocates small objects and increments Julia allocation counters. Size of the object | COMMENT |
| LOW | src/gc-interface.h | 221 | JL_DLLEXPORT void *jl_gc_counted_malloc(size_t sz); | COMMENT |
| LOW | src/gc-interface.h | 241 | // Permanently allocates a memory slot of the size specified by the first parameter. This | COMMENT |
| LOW | src/gc-interface.h | 261 | // must be either permanently allocated or have other roots. | COMMENT |
| LOW | src/gc-interface.h | 281 | JL_DLLEXPORT void jl_gc_wb_cold(const void *parent, const void *ptr) JL_NOTSAFEPOINT; | COMMENT |
| LOW | src/gc-interface.h | 301 | // can be used to annotate that a write barrier would be required were it not for this property | COMMENT |
| LOW | src/abi_arm.cpp | 1 | // This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| LOW | src/abi_arm.cpp | 181 | COMMENT | |
| 440 more matches not shown… | ||||
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | test/gcext/ForeignObjSerialization/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/gcext/Foreign/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/gcext/DependsOnForeign/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/manifest/v2.0/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/manifest/v1.0/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/project/Workspaces/PrecompileExt/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/project/ProjectPath/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | …/project/Extensions/EnvWithHasExtensions/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/project/Extensions/EnvWithDeps/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | …oject/Extensions/HasDepWithExtensions.jl/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | …xtensions/CrossPackageExtToExtDependency/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/project/Extensions/CyclicExtensions/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/project/Extensions/Parent.jl/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | …roject/Extensions/EnvWithHasExtensionsv2/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/project/Extensions/HasExtensions.jl/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | …st/project/Extensions/ExtToExtDependency/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/project/deps/BadStdlibDeps/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/project/deps/BadStdlibDeps2/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/project/SyntaxVersioning/explicit/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | test/project/SubProject/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | contrib/prepare_release.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/delete-all-rpaths.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/fixup-rpath.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/install.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/new-stdlib.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/fixup-libgfortran.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/commit-name.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/download_cmake.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/fixup-libstdc++.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/tsan/build.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/mac/app/renotarize_dmg.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/mac/app/notarize_check.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | contrib/asan/build.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| MEDIUM | JuliaSyntax/docs/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | deps/jlutilities/juliac/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | deps/jlutilities/documenter/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | deps/jlutilities/revise/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | deps/jlutilities/objectfile/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | stdlib/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | stdlib/TOML/benchmark/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | stdlib/TOML/docs/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | Compiler/test/CompilerLoadingTest/Manifest.toml | 1 | # This file is machine-generated - editing it directly is not advised | COMMENT |
| MEDIUM | base/version_git.sh | 2 | # This file is a part of Julia. License is MIT: https://julialang.org/license | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | doc/src/devdocs/sanitizers.md | 73 | #### Step 1: Install toolchain | COMMENT |
| LOW | doc/src/devdocs/sanitizers.md | 93 | #### Step 2: Build Julia with ASAN | COMMENT |
| LOW | src/gf.c | 4526 | // NOTE: This function is a huge performance hot spot!! | COMMENT |
| LOW | src/typemap.c | 219 | // NOTE: This function is a huge performance hot spot!! | COMMENT |
| LOW | src/typemap.c | 240 | // NOTE: This function is a performance hot spot!! | COMMENT |
| LOW | src/julia_internal.h | 1910 | // NOTE: This function is a huge performance hot spot!! | COMMENT |
| LOW | src/datatype.c | 2680 | // Step 1: Create empty DataTypes for each type in the typegroup | COMMENT |
| LOW | src/datatype.c | 2715 | // Step 2: Resolve type parameters and set up wrapper UnionAlls | COMMENT |
| LOW | src/datatype.c | 2740 | // Step 3: Resolve supertypes (after wrapper UnionAlls are set up) | COMMENT |
| LOW | src/datatype.c | 2775 | // Step 4: Resolve field types | COMMENT |
| LOW | src/datatype.c | 2860 | // Step 6: Reinstantiate inner types | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | src/datatype.c | 2680 | // Step 1: Create empty DataTypes for each type in the typegroup | COMMENT |
| LOW | src/datatype.c | 2715 | // Step 2: Resolve type parameters and set up wrapper UnionAlls | COMMENT |
| LOW | src/datatype.c | 2740 | // Step 3: Resolve supertypes (after wrapper UnionAlls are set up) | COMMENT |
| LOW | src/datatype.c | 2775 | // Step 4: Resolve field types | COMMENT |
| LOW | src/datatype.c | 2860 | // Step 6: Reinstantiate inner types | COMMENT |
| LOW | src/method.c | 1392 | // This section handles method roots. Roots are GC-preserved items needed to | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | contrib/fixup-libgfortran.sh | 122 | # don't care about full paths, we just set the rpath to `$ORIGIN`. | COMMENT |
| MEDIUM | src/codegen.cpp | 6125 | // This shouldn't happen in well-formed input, but let's be robust, | COMMENT |
| MEDIUM | src/julia_internal.h | 1680 | //TODO: utilize https://github.com/openssl/openssl/blob/master/crypto/rand/rand_uniform.c#L13-L99 | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| HIGH | doc/src/base/scopedvalues.md | 246 | # it, unshare the values explicitly. In this example we use `merge` | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | src/gc-stock.c | 3317 | // compute some guardrails values | COMMENT |
| MEDIUM | src/gc-stock.c | 3337 | // then add the guardrails for transient issues | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | test/clangsa/lit.cfg.py | 2 | CODE | |
| LOW | test/clangsa/lit.cfg.py | 3 | CODE | |
| LOW | test/llvmpasses/lit.cfg.py | 2 | CODE | |
| LOW | test/llvmpasses/lit.cfg.py | 3 | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | contrib/tsan/build.sh | 5 | # Usage: | COMMENT |
| LOW | contrib/asan/build.sh | 5 | # Usage: | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | stdlib/CompilerSupportLibraries_jll/Project.toml | 4 | # NOTE: When updating this, also make sure to update the value | COMMENT |
| LOW | src/gc-stock.c | 2845 | // Don't forget to clear the remset | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | src/cgutils.cpp | 542 | // if (!inlined) { // TODO: implement this filter operation | COMMENT |