Confusin about rust deref and ref

everyone, I am a beginner of rust,and I have read the rust book and rust reference.I am confused about which condition that rust compiler automatic Deref or Ref when using a method call. for example:sometimes when call the method like value.methond1() where value is type of T and T implement the method1,then value will be auto Deref or Ref.can anyone give me a summary conclusion about rust auto Deref and Ref