CMP0115
-------

.. versionadded:: 3.20

Source file extensions must be explicit.

In CMake 3.19 and below, if a source file could not be found by the name
specified, it would append a list of known extensions to the name to see if
the file with the extension could be found. For example, this would allow the
user to run:

.. code-block:: cmake

  add_executable(exe main)

and put ``main.c`` in the executable without specifying the extension.

Starting in CMake 3.20, CMake prefers all source files to have their extensions
explicitly listed:

.. code-block:: cmake

  add_executable(exe main.c)

The ``OLD`` behavior for this policy is to implicitly append known extensions
to source files if they can't be found. The ``NEW`` behavior of this policy is
to not append known extensions and require them to be explicit.

.. |INTRODUCED_IN_CMAKE_VERSION| replace:: 3.20
.. |WARNS_OR_DOES_NOT_WARN| replace:: warns
.. include:: include/STANDARD_ADVICE.rst

.. include:: include/DEPRECATED.rst