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class aaa = 
  object
    method test = 0 
  end;;
  
let test1 obj =
  let i = obj#test in i+1;;
  
let test2 obj = 
  let i = obj#test 
  and k = obj#test2 in i+k;;
  
let obj = new aaa in
let a = test1 obj 
(*OK*)
and b = test2 obj in a+b;;
(*Compile error. This expression has type aaa but is here used with type
  < test : int; test2 : int; .. >
The first object type has no method test2*)

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type aaa = 
  class 
    new() = { }
    member x.test = 0
  end
  
let test1 obj =
  let i = obj.test
  i+1
  
let test2 obj = 
  let i = obj.test
  let k = obj.test2
  i+k
  
let obj = new aaa()
let a = test1 obj 
let b = test2 obj
a+b