New in version 3.18.

It is not allowed to create an ALIAS target with the same name as an another target.

In CMake 3.17 and below, an ALIAS target can overwrite silently an existing target with the same name.

The OLD behavior for this policy is to allow target overwrite.

The NEW behavior of this policy is to prevent target overwriting.

This policy was introduced in CMake version 3.17. Use the cmake_policy() command to set it to OLD or NEW explicitly. Unlike many policies, CMake version 3.18.20200814-g83d940f does not warn when this policy is not set and simply uses OLD behavior.


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