anchor.diff:  // Control structures.
   
   condition
  -    : expression | existsCondition | nonemptyCondition | isCondition
  +    : expression 
  +    | existsCondition 
  +    | nonemptyCondition 
  +    | isCondition 
  +    | satisfiesCondition
       ;
   
   existsCondition
  
positive.code:     ;
  
  caseCondition
      : expressions | isCaseCondition
      ;
  
  expressions
  
negative.code:     -> ^(IS_EXPR type memberName? specifier? expression?)
      ;
  
  satisfiesCondition
      : 'satisfies' type type
      ;
  
  controlStructure
      : ifElse | switchCaseElse | simpleWhile | doWhile | forFail | tryCatchFinally
      ;
  