Idea: Check if let is equivalent to super()

[dgollahon]

This is tricky and might cause crashes or false positives but this could either take the form of trying to locate and parse the source and seeing if the implementation is the same or (more useful) calling super() and introspecting on the results. The problem with the latter is that it might not be valid. We could rescue any errors and only compare on success but my guess is that it would make rspectre less stable to even try this. It might make an interesting separate subcommand or opt-in.