anchor.diff:    void tryCatchStatement_end() {
       _TryContext<Variable, Type> context =
           _stack.removeLast() as _TryContext<Variable, Type>;
  -    _current = context._afterBodyAndCatches.unsplit();
  +    _current = context._afterBodyAndCatches!.unsplit();
     }
   
     @override
  
positive.code:       Variable? exceptionVariable, Variable? stackTraceVariable) {
      _TryContext<Variable, Type> context =
          _stack.last as _TryContext<Variable, Type>;
      _current = context._beforeCatch;
      if (exceptionVariable != null) {
        _current = _current.declare(exceptionVariable, true);
      }
  
negative.code:         'No assigned variables info should have been stored for $finallyBlock');
      _TryFinallyContext<Variable, Type> context =
          _stack.removeLast() as _TryFinallyContext<Variable, Type>;
      _current = context._afterBodyAndCatches!
          .attachFinally(typeOperations, context._beforeFinally, _current);
    }
  
  