anchor.diff:  specifier
       : '=' expression
       -> ^(INIT_EXPR expression)
  -    ;
  -
  -structured
  -    : (memberName | typeName) namedArguments
       ;
   
   nonstringLiteral
  
positive.code:     ;
  
  memberParameters
      : typeParameters? formalParameters+ extraFormalParameters typeConstraints?
      ;
  
  //TODO: should we allow the shortcut style of method
  
negative.code:     ;
  
  typeClass
      : 'is' (memberName | type)
      ;
  
  typeConstraint
  