Another exception was thrown: instance of ‘diagnosticsproperty‘

When you see the error message “another exception was thrown: instance of ‘diagnosticsproperty<void>’,” it means that an exception was thrown within your code and was not properly handled.

This error usually occurs when you have a statement or function call that is expected to return a value, but it doesn’t. The returned value is then treated as a void, which leads to the exception being thrown.

Let’s consider an example:

      
        void main() {
          int result = divide(10, 0);
          print(result);
        }
        
        int divide(int a, int b) {
          return a / b;
        }  // This code will throw the mentioned exception.
      
    

In this example, the divide function is called with arguments 10 and 0, which will raise an exception since you cannot divide by zero. The return type of the divide function is int, so the caller expects an integer value to be returned. However, since an exception is thrown before the result is returned, the returned value is void, which causes the exception “instance of ‘diagnosticsproperty<void>'” to be thrown.

To fix this issue, you need to handle the exception appropriately. One way to handle it is by using try-catch blocks:

      
        void main() {
          try {
            int result = divide(10, 0);
            print(result);
          } catch (e) {
            print("An exception occurred: $e");
          }
        }
        
        int divide(int a, int b) {
          try {
            return a / b;
          } catch (e) {
            throw Exception("Cannot divide by zero.");
          }
        }
      
    

In this updated code, the divide function is enclosed within a try block, which attempts to perform the division. If an exception occurs, it is caught and a custom Exception is thrown with an appropriate error message. The main function also contains a try-catch block to handle any exceptions that may occur.