let f = f;

ReferenceError: can’t access lexical declaration ‘f’ before initialization

I understand that variable declaration proceeds in three steps.

1. Declaration
2. initialization
3. Assignment

So why does the above code produce a reference error?

1. Declaration (TDZ)
2. let f = f; Reach declaration statement
   let f = undefined; //initialization
   let f = f; //Why did a reference error occur?

I read the book but there is no answer