Run Swig always with -Werror; disable dispensable warnings.

Wrap/swig/warnings.i

+// unproblematic warnings, keep them permanently disabled:
 #pragma SWIG nowarn=314 // print conflicts with Python, renamed to _print
 #pragma SWIG nowarn=315 // nothing known about std::size_t
-#pragma SWIG nowarn=362 // operator=
-#pragma SWIG nowarn=389 // operator[]
-#pragma SWIG nowarn=473 // returning pointer in a director method (object ownership problem)
-#pragma SWIG nowarn=503 // operator<<
-#pragma SWIG nowarn=509 // overload ignored since reference=pointer
-#pragma SWIG nowarn=520 // shared_ptr not declared for entire hierarchy [stackoverflow 11380483]
+#pragma SWIG nowarn=362 // operator= ignored
+#pragma SWIG nowarn=389 // operator[] ignored, consider %extend
+#pragma SWIG nowarn=503 // operator= ignored, consider renaming to valid identifier
+
+// questionable warnings, TODO: reinvestigate
+#pragma SWIG nowarn=473 // questionable return pointer
+#pragma SWIG nowarn=509 // overloaded method shadowed, effectively ignored

cmake/BornAgain/SwigLib.cmake

@@ -27,7 +27,11 @@ function(SwigLib name lib TMP_DIR)
         endforeach()
         list(APPEND swig_dependencies ${AUTO_DIR}/doxygen${name}.i)
 
-        set(SWIG_FLAGS "-c++;-python;-o;${AUTO_DIR}/lib${lib}_wrap.cpp;-outdir;${TMP_DIR}"
+        # Run Swig.
+        #     Please keep -Werror, in order not to overlook critical warnings.
+        #     Dispensable warnings are disabled in Wrap/swig/warnigs.i.
+        #     Joachim, oct20.
+        set(SWIG_FLAGS "-c++;-python;-Werror;-o;${AUTO_DIR}/lib${lib}_wrap.cpp;-outdir;${TMP_DIR}"
                                ";-I${CMAKE_SOURCE_DIR};-I${CMAKE_BINARY_DIR}/inc")
 
         add_custom_command(