anchor.diff:    | breakStatement
     | returnStatement
     | throwStatement
  +  | emitStatement
     | simpleStatement ;
   
   expressionStatement
  
positive.code:   : '{' nameValueList? '}'
    | expressionList? ;
  
  assemblyBlock
    : '{' assemblyItem* '}' ;
  
  
negative.code:     ( 'returns' functionTypeParameterList )? ;
  
  storageLocation
    : 'memory' | 'storage' | 'calldata';
  
  stateMutability
    : PureKeyword | ConstantKeyword | ViewKeyword | PayableKeyword ;
  