[SR-13656] Quick Help does not work for closure parameters

[pwightman]

Previous ID	SR-13656
Radar	rdar://problem/69979000
Original Reporter	@pwightman
Type	Bug
Status	Closed
Resolution	Invalid

Attachment: Download

Additional Detail from JIRA

Votes	0
Component/s	Source Tooling
Labels	Bug
Assignee	None
Priority	Medium

md5: 4a13d4044e7b729d5ac80603e66587ad

Issue Description:

Quick Help in Xcode does not show type information for closure params, but does for usages of the param within the closure body.

Affected Xcode versions: This has been the case since Swift was released AFAIK, I never remember it working, but definitely Xcode 10, 11 & 12.

Example:

let _: (Int) -> Void = { num in // <- option-clicking 'num' here does not show type info
    print(num) // <- option-clicking here does show type info
}

Option-clicking closure params is something I want to do very often, as a means of exploring types of unfamiliar APIs, or to know which order the params come in, e.g. "does [1, 2, 3].enumerated() return (index, num) or (num, index)?"

Workarounds include: using the parameter in the function body and option-clicking, or manually looking up the documentation for the function.

Screenshots:

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[typesanitizer]

@swift-ci create

[akyrtzi]

Thanks for reporting this but this is an Xcode-side issue, not Swift tooling one. It would not be fixed with a change in the Swift repository, so a Swift Jira issue is not applicable.

I'd recommend to file a bug report at https://feedbackassistant.apple.com so you can follow when an Xcode release has this fixed.