Description Ran Ettinger 2005-09-12 09:08:46 EDT

Trying to apply the Extract Method refactoring on the following selection 
results in an unnecessary rejection.

Original program: 

  private int g(boolean b) {
    int n = 10;
    int i = 0;
    while (i < n) {
      if (b) {
        // Extract Method from here
        i++;
        n -= i;
	// to here
        break;
      }
      else i++;
    }
    return n;
  }

Applying Extract Method on the selected code (signalled by the comments)
results in a rejection with the message: "Ambiguous return value: selected 
block contains more than one assignment to local variable".

In fact, because of the "break" statement, only the modified local variable n 
should be returned. The local variable i will never be relevant on return from 
the extracted method. As a result, variable i can be localized in the new 
method.

I expected the refactored source to look like this:

  private int g(boolean b) {
    int n = 10;
    int i = 0;
    while (i < n) {
      if (b) {
        n = newMethod(i, n);
        break;
      }
      else i++;
    }
    return n;
  }

  private int newMethod(int i, int n) {
    i++;
    n -= i;
    return n;
  }