C++ Insights – See your source code with the eyes of a Compiler

C++ Insights is a Clang-based source-to-source transformer that makes compiler-generated behavior explicit in readable C++. It rewrites constructs such as range-based for-loops, lambdas, structured bindings, implicit casts, and auto/decltype deductions into the forms the compiler actually uses, exposing defaulted special member functions, operator calls, and casts (for example, turning a copy-initialization into an explicit constructor call and an upcast into a static_cast). The tool strives to emit compilable code so readers can inspect the "behind the scenes" transformations in familiar syntax, and an online demo is available at cppinsights.io. The project documents what it implements, shows concrete before/after examples, and notes that support evolves as new C++ standards are added.

The repository provides build and usage instructions for multiple environments: building inside or outside the Clang tree, platform-specific notes for Windows, Arch Linux, and macOS ARM, and CMake options (strip, static linking, coverage, libc++ selection, debug). It also documents runtime issues like system-include path handling and supplies scripts/getinclude.py to collect include flags, a gcc-toolchain option to point Clang at a custom libstdc++ installation, and a ready-to-use Docker setup maintained elsewhere. Accuracy depends on Clang’s AST, work on C++20 features is ongoing, and contributors are guided by contributing and testing files included in the repo.