flatpipes is (partly) unsafe without Pod kind

[brson]

The flatpipes module has a mode that works with POD types, and it declares the bounds with Copy Send, but Copy Send is not the same as POD. In particular it allows unique pointers and region pointers. Unique pointers will no longer be Copy once type-based move is implemented. Not sure about regions.

[graydon]

I'm a bit unclear about what this means.

• Why is an owning pointer going to stop being Copy?
• What do you intend to capture by POD? Owning pointers and region pointers? Managed pointers? Cycles?

[brson]

I thought that the class of not-implictly-copyable things was going away with type-based move, but now I can't remember why. Certainly we have been saying that the 'copy' and 'move' keywords would go away, and without 'copy' you can't copy a unique pointer.

I don't understand the word 'capture' in the second question. I intend for POD to mean scalar types and aggregates of scalar types that don't require allocation. No pointers.

[catamorphism]

Not critical for 0.6; de-milestoning

[bstrie]

According to brson, this is still relevant. Nominating for Maturity 3, Feature Complete.

[pcwalton]

This is part of extra so probably not a backwards compatibility issue.

[graydon]

accepted for production-ready milestone

[brson]

If we don't get Pod then we should remove this mode of flatpipes.

[thestinger]

Visiting for triage, still an unsolved issue.

[brson]

Flatpipes no longer exists.