[SR-2008] Implement SE-0110: Distinguish between single-tuple and multiple-argument function types

[lattner]

Previous ID	SR-2008
Radar	rdar://problem/27383557
Original Reporter	@lattner
Type	Task
Status	Resolved
Resolution	Done

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Task, StarterBug
Assignee	@slavapestov
Priority	Medium

md5: 83ce6240317526d0237e3fdd515173d3

relates to:

• SR-2135 Multiple Tuple Parameters to a Closure cannot be Decomposed in the Parameter List

Issue Description:

SE-0110 has been accepted, we just need an implementation!
https://github.com/apple/swift-evolution/blob/master/proposals/0110-distingish-single-tuple-arg.md

[dduan]

Part I (disallow multi-argument to tuple coercion) implemented: #3895

[swift-ci]

Comment by Paul Meng (JIRA)

An attempt to implement the full SE-0110: #4102

[jtbandes]

PaulMeng (JIRA User), is this done?

[swift-ci]

Comment by Paul (JIRA)

Yes. It's merged.

[swift-ci]

Comment by Paul Meng (JIRA)

Uh, sorry. Logged-in with the wrong account. It's merged.

[DougGregor]

This is done, but didn't make it into Swift 3

[swift-ci]

Comment by Alex Martini (JIRA)

The implementation was reverted:

f42158b

[swift-ci]

Comment by Paul Meng (JIRA)

Let me look into it and propose a fix.

[swift-ci]

Comment by Greg Lutz (JIRA)

I was hoping that the implementation of SE-0110 would end up fixing SR-1795, but I'm not so sure it will. The point is, if single-tuple and multiple-argument functions are distinguishable, they'd damn well better mangle to different names! So they can, for example, co-exist in the same module.

[benrimmington]

apple/swift#3895 was reverted by apple/swift#3922 (aka apple/swift@f42158b).

apple/swift#4102 has not been reverted yet.

[DougGregor]

The SE-0110 implementation on master is a bit of a mess right now. SE-0110 is partially implemented, but doesn't restrict all of the cases it should restrict, and doesn't provide backward compatibility in the Swift 3 compatibility mode.

[swift-ci]

Comment by Fabian Ehrentraud (JIRA)

Will this fix SR-2135 too?

[slavapestov]

I implemented this on master in this PR: #6133

[swift-ci]

Comment by Raphael (JIRA)

It is not clear to me from the SE if

[benrimmington]

@reitzig (JIRA User): I think it would be an error in -swift-version 4 mode:

• swift/test/Constraints/tuple_arguments.swift

• Should we require parentheses in closure expression parameter lists?

• Tuple Destructuring in Parameter Lists