swiftlang/swift

[SR-7151] Generalize CaseIterable Synthesis for Availability

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#49,699 opened on Mar 9, 2018

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Description
Previous ID SR-7151
Radar rdar://problem/43569215
Original Reporter @CodaFi
Type Improvement
Status In Progress
Resolution
Votes 2
Component/s Compiler
Labels Improvement, StarterBug
Assignee None
Priority Medium

md5: 508eab090d1f0026b4428b290a2d40be

relates to:

  • SR-9094 Unavailable enum case with synthesized raw value causes error

Issue Description:

As of this issue, the current implementation of SE-0194 does not synthesize a conformance if any cases contain an availability attribute. This restriction may be lifted at any time by an implementation that maintains the source-order invariant.

enum Rhapsody: CaseIterable {
  @available(*, unavailable)
  case inBlue 
  case hungarian, bohemian
  @available(*, deprecated)
  case onATheme
}
Rhapsody.allCases // [hungarian, bohemian, onATheme]

Contributor guide

Research direction
Study the existing CaseIterable synthesis implementation in the Swift compiler. Modify the synthesis logic to include cases with @available attributes except those marked as unavailable, while maintaining the source order invariant.
Tech stack
swift
Domain
compilers
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Swift
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70