Check for forgotten use statements

Hello, 

I am debugging a code that mysteriously fails on me. The code uses a lot of use statements to make things modular. How can I check whether I forgot to put such a USE stament in one of the calling routines? The compiler will resolve these calls during linking with the result that the interface is probably no good with strange things happening. The Warn interfaces (or all) option does not seem to tell me anything (also not sure what it does exactly). Is there a way to be sure that no USE statements are missing? Thank you. Danny.