Make TaskBuilder methods return Self again so we can use the builder pattern.

[metajack]

Specifically sched_mode() now returns () instead of the builder. This broke servo code using the following pattern:

task::task().sched_mode(Foo).spawn {
    ....
}

EDIT(bblum): All methods seem to return (). They should all return Self except for the spawn methods.

[metajack]

nominating for backwards compatible

[graydon]

accepted for backwards-compatible milestone

[nikomatsakis]

Blocked on #5967

[nikomatsakis]

(Allowing rvalues to be mutably borrowed)

[sanxiyn]

This is unblocked?

[bblum]

Looks like it is.

[pnkfelix]

visited for bug triage, email 2013-08-19.

It sounds from the comments like someone should take a shot at doing this, since #5967 is now fixed.

I'm looking into it. Niko says it may still not work well; "you'll find you can't chain more than one or two calls..."

[nikomatsakis]

To clarify, this is due to issue #3511, which I hope to address soon.

[pnkfelix]

(I have abandoned PR #8708; others are free to resurrect it if they like.)

[lilac]

Is this unblocked by recent progress in #3511 ?

[pnkfelix]

@lilac I remain unclear as to whether the actual goal here is to implement the multable-builder pattern or the immutable one; see the dialogue on PR #8708

@alexcrichton @metajack can you shed some light on this question? (Not that I dont trust bblum's statements, but I figure I'd rather get a thumbs-up from someone within the current core team.)

[alexcrichton]

I would guess that this is unblocked, but there's only one way to find out!

[pnkfelix]

@alexcrichton sorry, by "shed some light on this question", I meant this question:

• is the actual goal here is to implement the mutable-builder pattern or the immutable one?

[alexcrichton]

I don't particularly have an opinion one way or another, I wasn't around for the time that this looked like it existed. I'm not sure how commonly this is used and whether we still want to switch.

[alexcrichton]

Sorry that doesn't really shed any more light than before :(