A quick note, in the feature subcluster of the compiler

feature assigner: FEATURE_NAME -- If this feature can be assigned to, the assigner feature name.

is declared in ANONYMOUS_FEATURE while it seems to me a little too generic. Also EFFECTIVE_ROUTINE is "too wide" as it is kown children are E_FUNCTION, E_PROCEDURE, ONCE_ROUTINE, and E_FUNCTION can't be an assign an attribute

Shouldn't it be declared into E_PROCEDURE?

A class processed by pretty loses its assigns:

class FOO
feature
  value: INTEGER
  set_value(a_value:INTEGER) assign value
  do
    value:=a_value
  end
end

is changed by pretty into

class FOO
feature
  value: INTEGER
  set_value(a_value:INTEGER)
  do
    value:=a_value
  end
end

Quite obviously it will break other people code.