Suspicious calculation of sourceEnd in JDTTreeBuilderHelper#createTypeAccessNoClasspath

[msteinbeck]

In JDTTreeBuilderHelper#createTypeAccessNoClasspath the following code is used to calculate sourceEnd:

int sourceEnd = (int) (positions[qualifiedNameReference.indexOfFirstFieldBinding - 1] >>> 32) - 2;

I'm wondering why you don't use:

int sourceEnd = qualifiedNameReference.sourceEnd();

instead? I have a case in which qualifiedNameReference.indexOfFirstFieldBinding is 0 and, therefore, an ArrayIndexOutOfBoundsException is thrown.