# CMP0057

Warning

The `OLD` behavior of this policy was removed in CMake version 4.0. This policy must be set to `NEW` by a call to `cmake_minimum_required()` or `cmake_policy()`.

Added in version 3.3.

Support new `if()` IN_LIST operator.

CMake 3.3 adds support for the new IN_LIST operator.

The `OLD` behavior for this policy is to ignore the IN_LIST operator. The `NEW` behavior is to interpret the IN_LIST operator.

This policy was introduced in CMake version 3.3. Prior to removal in CMake version 4.0, it could be set by `cmake_policy()` or `cmake_minimum_required()`. If it was not set, CMake warned, and used `OLD` behavior.