anchor.diff:      |   'goto' unaryExpression ';' // GCC extension
       ;
   
  -compilationUnit
  -    :   translationUnit? EOF
  -    ;
  -
  -translationUnit
  -    :   externalDeclaration
  -    |   translationUnit externalDeclaration
  -    ;
  -
  -externalDeclaration
  -    :   functionDefinition
  -    |   declaration
  -    |   ';' // stray ;
  -    ;
  -
  -functionDefinition
  -    :   declarationSpecifiers? declarator declarationList? compoundStatement
  -    ;
  -
  -declarationList
  -    :   declaration
  -    |   declarationList declaration
  -    ;
  +//compilationUnit
  +//    :   translationUnit? EOF
  +//    ;
  +//
  +//translationUnit
  +//    :   externalDeclaration
  +//    |   translationUnit externalDeclaration
  +//    ;
  +//
  +//externalDeclaration
  +//    :   functionDefinition
  +//    |   declaration
  +//    |   ';' // stray ;
  +//    ;
  +//
  +//functionDefinition
  +//    :   declarationSpecifiers? declarator declarationList? compoundStatement
  +//    ;
  +//
  +//declarationList
  +//    :   declaration
  +//    |   declarationList declaration
  +//    ;
   
   Break : 'break';
   Case : 'case';
  
positive.code: 
  blockItem
      :   statement
      |   declaration
      ;
  
  expressionStatement
  
negative.code: assignmentExpression
      :   conditionalExpression
      |   unaryExpression assignmentOperator assignmentExpression
      ;
  
  assignmentOperator
  