port-from-cpplisted

# Port from C++ ## A construct mapping and a boundary, nothing else This skill maps C++ to Rust and owns the C++ boundary. The parity contract, the five phases, and the anti-patterns are `/port-to-rust`, which runs first and stays running through the port. C is a separate skill — the mechanics overlap, the idioms do not — so a C codebase with a `.cpp` extension is still `/port-from-c` territory in everything but the build. ## The end state, and the C++ default `/port-to-rust` names three end states. In C++ terms: A, a standalone Rust binary or library replacing the C++ entirely; B, a Rust core with a permanent C++-callable surface, real when the deliverable is a library other C++ code links; and C, a bridge that carries the migration module by module and is deleted at cut-over. **C is the default for C++**, more than for any other language in this set: a large C++ codebase cannot be replaced in one step, and the seam — a Rust `staticlib` linked into the existing build — lets leaf modules move one at a time. The bridge is disposable scaffolding that must still be *sound*, and that tension is what this skill manages; the mechanics are in `BOUNDARY.md`. ## The traps that break parity silently The body carries these five because each one produces a port that passes a naive test suite and is wrong; the full table is `MAPPING.md`. | Trap | What actually differs | |---|---| | Undefined behaviour was doing something | Signed overflow, strict aliasing violations, reading uninit