Enum tuple case composing/decomposing disparity

[xwu (Xiaodi Wu)]

@tera

Could we fix it one way or another and make the composing & decomposing behaviours aligned?

This is covered in:

SE-0155 Status Update

Hello Swift Community, In late August of last year, a revision of SE-0155 was approved by the core team and the responsibility for its implementation was discharged to me after I responded to a call for implementors. As many of you have noticed, we are now at Swift 4.2 and there is not an implementation of this proposal that has made it into master. I'm writing this to update you all on the current status of the implementation of SE-0155, and to issue reflections on its implementation now tha…

Specifically:

Ungating the pattern matching revision reveals that a rather large amount of code is relying upon the existing Swift 3 pattern matching behavior around tuple element labels and neither the proposal nor the acceptance rationale provide a clear answer for how we wish to resolve this (see the issue thread ). If the community still feels that a source breaking change of this magnitude in the name of consistency is warranted, a revision that clearly spells out the rules for pattern matching should be drafted.

Simply pointing out that there is a disparity doesn't justify changing it; if it was too source breaking for Swift 4, it's hard to see how it's justifiable for Swift 6, but if you have a strong argument that hasn't been considered then by all means...