In order to test if it still produces aliasing errors I used

diff --git i/awkward-cpp/CMakeLists.txt w/awkward-cpp/CMakeLists.txt
index 574d197f..b0ea478b 100644
--- i/awkward-cpp/CMakeLists.txt
+++ w/awkward-cpp/CMakeLists.txt
@@ -2,6 +2,10 @@
 
 cmake_minimum_required(VERSION 3.15...3.30)
 
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror=strict-aliasing")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror=strict-aliasing")
+
+
 if(NOT DEFINED SKBUILD)
   set(SKBUILD_PROJECT_NAME awkward_cpp)
   set(SKBUILD_PROJECT_VERSION 0.0.0)

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.41%. Comparing base (b749e49) to head (9acd511).
Report is 369 commits behind head on main.

@henryiii - FYI, the windows build fails for 3.13 on this PR. Is it something you are looking into? Thanks!

*** Building project with Visual Studio 17 2022...
MSBuild version 17.13.15+18b3035f6 for .NET Framework

  Checking File Globs
  1>Checking Build System
  Building Custom Rule D:/a/awkward/awkward/awkward-cpp/CMakeLists.txt
  ArrayBuilder.cpp
  BoolBuilder.cpp
  Builder.cpp
  Complex128Builder.cpp
  DatetimeBuilder.cpp
  Float64Builder.cpp
  Int64Builder.cpp
  ListBuilder.cpp
  OptionBuilder.cpp
  RecordBuilder.cpp
  StringBuilder.cpp
  TupleBuilder.cpp
  UnionBuilder.cpp
  UnknownBuilder.cpp
  ForthInputBuffer.cpp
  ForthMachine.cpp
  ForthOutputBuffer.cpp
  json.cpp
  util.cpp
  Generating Code...
     Creating library D:/a/awkward/awkward/awkward-cpp/build/cpython-313/Release/awkward.lib and object D:/a/awkward/awkward/awkward-cpp/build/cpython-313/Release/awkward.exp
  awkward.vcxproj -> D:\a\awkward\awkward\awkward-cpp\build\cpython-313\Release\awkward.dll
  Building Custom Rule D:/a/awkward/awkward/awkward-cpp/CMakeLists.txt
  _ext.cpp
  content.cpp
  forth.cpp
  io.cpp
LINK : fatal error LNK1104: cannot open file 'python313t.lib' [D:\a\awkward\awkward\awkward-cpp\build\cpython-313\_ext.vcxproj]

*** CMake build failed

@henryiii - FYI, the windows build fails for 3.13 on this PR. Is it something you are looking into? Thanks!

*** Building project with Visual Studio 17 2022...
MSBuild version 17.13.15+18b3035f6 for .NET Framework

  Checking File Globs
  1>Checking Build System
  Building Custom Rule D:/a/awkward/awkward/awkward-cpp/CMakeLists.txt
  ArrayBuilder.cpp
  BoolBuilder.cpp
  Builder.cpp
  Complex128Builder.cpp
  DatetimeBuilder.cpp
  Float64Builder.cpp
  Int64Builder.cpp
  ListBuilder.cpp
  OptionBuilder.cpp
  RecordBuilder.cpp
  StringBuilder.cpp
  TupleBuilder.cpp
  UnionBuilder.cpp
  UnknownBuilder.cpp
  ForthInputBuffer.cpp
  ForthMachine.cpp
  ForthOutputBuffer.cpp
  json.cpp
  util.cpp
  Generating Code...
     Creating library D:/a/awkward/awkward/awkward-cpp/build/cpython-313/Release/awkward.lib and object D:/a/awkward/awkward/awkward-cpp/build/cpython-313/Release/awkward.exp
  awkward.vcxproj -> D:\a\awkward\awkward\awkward-cpp\build\cpython-313\Release\awkward.dll
  Building Custom Rule D:/a/awkward/awkward/awkward-cpp/CMakeLists.txt
  _ext.cpp
  content.cpp
  forth.cpp
  io.cpp
LINK : fatal error LNK1104: cannot open file 'python313t.lib' [D:\a\awkward\awkward\awkward-cpp\build\cpython-313\_ext.vcxproj]

*** CMake build failed

I guess, these changes need to go first:
d8219a1#diff-faff1af3d8ff408964a57b2e475f69a6b7c7b71c9978cccc8f471798caac2c88R99-R106

@all-contributors please add @APN-Pucky for code

@ianna

I've put up a pull request to add @APN-Pucky! 🎉

Thanks @ianna !