Title: Unchanged embedded scope
Goal: Rename variable `X' in the argument list of `f/1' to `Z'.
Parameters: [{file,"var3.erl"},{position,19},{varname,"Z"}].
Documentation: The occurrences of the variable `X' in the fun expression are not renamed, because the fun expression introduce a new scope and it is possible to introduce new variable in the pattern list with an existing name. 
