Because of the comfortable and intuitive debugging, we need to have the possibility to set a breakpoint on every line of an executable code.

E.g. in the following example it's possible to add breakpoints for lines 47, 49, 51, 52 and 53. But there are no locations on lines 48 and 50.

47: long exp = 0;
48: while (
49: f > 1e100
50: ) {
51: f /= 1e100;
52: exp += 100;
53: }

This is just for illustration, the problem also occurs when there is en expression accross several lines, etc. This is a source of user confusion.