anchor.diff:  propertyNameAndValueList
    : propertyAssignment ( ',' propertyAssignment )*
    ;
  -    
  +
   /// PropertyAssignment :
   ///     PropertyName : AssignmentExpression
   ///     get PropertyName ( ) { FunctionBody }
  
positive.code: fragment RegularExpressionClass
    : '[' RegularExpressionClassChar* ']'
    ;
   
  /// RegularExpressionClassChar ::
  ///     RegularExpressionNonTerminator but not ] or \
  ///     RegularExpressionBackslashSequence
  
negative.code: /// AssignmentOperator : one of
  ///     *=	/=	%=	+=	-=	<<=	>>=	>>>=	&=	^=	|=
  assignmentOperator
   : '*='
   | '/='
   | '%='
   | '+='
   | '-='
   | '<<='
   | '>>='
   | '>>>='
   | '&='
   | '^='
   | '|='
   ;
  
  literal
   : ( NullLiteral
     | BooleanLiteral
     | StringLiteral
     | RegularExpressionLiteral
  