anchor.diff:          typeClass?
           satisfiedTypes?
           typeConstraints?
  -        interfaceBody
  +        (classBody | typeSpecifier)
       ;
   
   interfaceBody
       : '{'! declaration* '}'!
  -    ;
  -
  -aliasDeclaration
  -    :
  -        'alias'!
  -        typeName
  -        typeParameters?
  -        typeConstraints?
  -        aliasBody
  -    ;
  -
  -aliasBody
  -    : '='! type ';'!
       ;
   
   classDeclaration
  
positive.code:     | 'interface' 
      | 'class' 
      | 'object'
      | 'alias'
      ;
  
  //by making these things keywords, we reduce the amount of
  
negative.code: specifier
      : '=' expression
      -> ^(INIT_EXPR expression)
      ;
  
  typeSpecifier
      : '='! type ';'!
      ;
  
  nonstringLiteral
  