llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-tools-extra Author: Jonas Toth (JonasToth) <details> <summary>Changes</summary> This PR improves the docs for this check to include an example of hidden narrowing conversions from the integer promotion rules in arithmetic. --- Full diff: https://github.com/llvm/llvm-project/pull/118209.diff 1 Files Affected: - (modified) clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/narrowing-conversions.rst (+15) ``````````diff diff --git a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/narrowing-conversions.rst b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/narrowing-conversions.rst index 04260e75aa558f..f4d1976ad4c688 100644 --- a/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/narrowing-conversions.rst +++ b/clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/narrowing-conversions.rst @@ -27,6 +27,21 @@ This check will flag: - All applications of binary operators with a narrowing conversions. For example: ``int i; i+= 0.1;``. +Note that arithmetic with integer types may perform implicit conversions if the used integer types are smaller than ``int``. +These rules are documented under `"Integral Promotion" on this cppreference.com <https://en.cppreference.com/w/cpp/language/implicit_conversion>`_ +page. The following example demonstrates this behavior and can be explored with `cppinsights.io <https://cppinsights.io/s/68553908>`_. + +.. code-block:: c++ + + // The following function definition demonstrates usage of arithmetic with integer types smaller than `int` + // and how the narrowing conversion happens implicitly. + void computation(short argument1, short argument2) { + // Arithmetic written by humans: + short result = argument1 + argument2; + // Arithmetic actually performed by C++: + short result = static_cast<short>(static_cast<int>(argument1) + static_cast<int>(argument2)); + } + Options ------- `````````` </details> https://github.com/llvm/llvm-project/pull/118209 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
