I am converting an application written in Objective C to Swift. Unfortunately Xcode is only recognizing the error type of the variables called. I tried deleting many files such as Module Cache, as many people told me the error is regarding Xcode memory, but that does not work. Need help to solve this issue.
I've seen this too. I think it comes from the project not being properly indexed yet, as a result of source code that still has errors, or hasn't been compiled yet. If you can get your project to build (perhaps by temporarily leaving some files out of the target, or by commenting stuff out, or providing temporary implementations of custom types), then you should find autocomplete showing the correct information.
But submit a bug report too.