IDL not generated correctly when there are tuple arguments

[gxxcastillo]

Bug Summary

Defining a function with a tuple as an argument results in the IDL not being generated correctly.

In this reproduction example, it doesn't generate the one function that has the tuple argument,
but in the case I ran into the other day there was a lot more missing than just the one function.

If having a tuple as an argument is not allowed, there should be an error message.

Reproduction Example + Steps

https://github.com/gxxcastillo/anchor-tuple-bug

1. > yarn install
2. anchor test

Expected Behavior

The tests in the reproduction repo should pass and the IDL should be generated correctly, OR, if the IDL is not supposed to be generated correctly, there should be a clear error message.