Implicit conversion long - size_t - int.Null dereference can sometimes be detected statically, e.g. when the variable is not initialized. Possible null dereference after downcast, though this one can be annoying.
I suggest to configure warnings with a config file, as the configuration can be big depending on the project code style. Another possibility is optional pragmas for really evil local overrides - resharper style comments - not only analysis tools can benefit from them.
