# CMP0057

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. It may be set by `cmake_policy()` or `cmake_minimum_required()`. If it is not set, CMake warns, and uses `OLD` behavior.

Note

The `OLD` behavior of a policy is `deprecated by definition` and may be removed in a future version of CMake.