Hello Everyone,

while casually looking at the rather complex code of the scala.collection.immutable.Vector implementation I found some odd lines of code and one that I believe to be a bug:

in line 1196 it looks like the newIndex is supposed to be shifted by >>25 but is actually shifted by 20.

I have tried to reproduce a bug in Scala code but failed to do so. From what I understand one has to append or prepend something to a position that is more than 1<<25 positions away from the last written position. But the appendFront and appendBack methods are rather complex and stateful to the extend that I can't figure out which other conditions need to be met.

While I am at it:
There also seem to be completely redundant Array allocations in there, which are probably optimized away by the compiler's (escape analysis?), but they are redundant none the less... right?:

L1159-L1160
L1174-L1175
L1190-L1193