I want to add a source file (which is under GPL v2.0 (not in v2.0+)) in a project which is under Apache 2.0 license.
As mentioned on GNU's website
Please note that this license is not compatible with GPL version 2 ...
this word is used for Apache 2.0 license.
I wonder, can I add a source file which is under different license and incompatible with project license? And what would? If I explicitly mention about that file and its license in a LICENSE file (usually this file is present in root directory of the project).