Detect source unit name collisions between paths specified on the command line

docs/path-resolution.rst

@@ -392,6 +392,16 @@ Otherwise the file path remains absolute.
 This makes the conversion unambiguous and ensures that the relative path does not start with ``../``.
 The resulting file path becomes the source unit name.
 
+.. note::
+
+    The relative path produced by stripping must remain unique within the base path and include paths.
+    For example the compiler will issue an error for the following command if both
+    ``/project/contract.sol`` and ``/lib/contract.sol`` exist:
+
+    .. code-block:: bash
+
+        solc /project/contract.sol --base-path /project --include-path /lib
+
 .. note::
 
     Prior to version 0.8.8, CLI path stripping was not performed and the only normalization applied