Generally, follow the Chromium style guide for C++ which itself is built on the Google C++ style guide.
Overall try to use the same style and convention as code around your change.
Code must be formatted. Use clang-format with the provided .clang-format file. The tools/format script runs the formatter.
Code should not have linting errors. The tools/lint script runs the linter. So does git cl upload.
Do not use C++ exceptions
Do not use C++ RTTI. Instead, use tint::Castable::As<T>() from src/castable.h
Generally, avoid assert. Instead, issue a diagnostic and fail gracefully, possibly by returning an error sentinel value. Code that should not be reachable should call TINT_UNREACHABLE macro and other internal error conditions should call the TINT_ICE macro. See src/debug.h
Use type as part of a name only when the name refers to a type in WGSL or another shader language processed by Tint. If the concept you are trying to name is about distinguishing between alternatives, use kind instead.
Tint requires C++17.
Tint uses the Chromium build system and will stay synchronized with that system. Compiler configurations beyond that baseline is on a best-effort basis. We strive to support recent GCC and MSVC compilers.
We might relax the above rules rules for test code, since test code shouldn't ship to users.
However, test code should still be readable and maintainable.
For test code, the tradeoff between readability and maintainability and other factors is weighted even more strongly toward readability and maintainability.