LinearSeq extension problem solved

[vincentdehaan]

When extending a LinearSeq, calling iterator resulted in an
infinite loop causing a StackOverflowError.

Fixes scala/bug#11262

[vincentdehaan]

I just signed the CLA.

[NthPortal]

While this does fix the problem here, the underlying issue I believe is that toSeq is broken for LinearSeq (it should just return this or coll or something). I think it would be better to fix toSeq instead.

[vincentdehaan]

The problem was indeed that toSeq was broken for LinearSeq. This was caused by an infinite loop of which both toSeq and iterator (and a handful of other methods, as shown by the stack trace) are part. This seemed to be the most elegant way to fix it, and toSeq has been fixed as well.

[julienrf]

Indeed, toSeq should return this, what’s the current behaviour?

[NthPortal]

@julienrf immutable.Seq.from(this), inherited from IterableOnceOps

[julienrf]

Actually, this is normal, only the immutable.Seq can implement toSeq by returning this. The default behaviour is to build a List from the receiver’s iterator. However, the current implementation of iterator in LinearSeq calls toSeq, hence the infinite loop. So, this PR contains the correct fix.