llvm-project/clang-tools-extra/docs/clang-tidy/checks/modernize-use-transparent-f...

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.. title:: clang-tidy - modernize-use-transparent-functors
modernize-use-transparent-functors
==================================
Prefer transparent functors to non-transparent ones. When using transparent
functors, the type does not need to be repeated. The code is easier to read,
maintain and less prone to errors. It is not possible to introduce unwanted
conversions.
.. code-block:: c++
// Non-transparent functor
std::map<int, std::string, std::greater<int>> s;
// Transparent functor.
std::map<int, std::string, std::greater<>> s;
// Non-transparent functor
using MyFunctor = std::less<MyType>;
It is not always a safe transformation though. The following case will be
untouched to preserve the semantics.
.. code-block:: c++
// Non-transparent functor
std::map<const char *, std::string, std::greater<std::string>> s;
Options
-------
.. option:: SafeMode
If the option is set to non-zero, the check will not diagnose cases where
using a transparent functor cannot be guaranteed to produce identical results
as the original code. The default value for this option is `0`.
This check requires using C++14 or higher to run.