In certain situations, a file generated by add_custom_command(OUTPUT) may be added as a source to a target defined in a different directory scope. That makes its GENERATED source property not visible to the target for CMake versions before 3.20. For 3.20 and later, policy CMP0118 can make the generated state of a source file global, but that policy is under the control of the user project, since its value at the end of the target's directory scope is what is used. Therefore we can force that global visibility using CMP0118. With CMake 3.18 or later, we can set source properties in arbitrary scopes, which allows us to force visibility in the scopes we need it. Use that for all CMake versions 3.18 and later to make the source file properties visible to the target. Making the generated state of a source file visible to the target isn't enough on its own. In the scope that the file is generated, there must be a target that depends on the file or else CMake won't set up the necessary dependencies to ensure that generation happens before the target tries to use it. Add targets in the generated file's own scope where we currently might not do that. Task-number: QTBUG-95200 Pick-to: 6.2 Change-Id: Ic1dfca1a193041de01d7f903b79473b9d47f1d1d Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>