swiftlang/swift

[SR-9789] Use "pretty" nullability in generated ObjC headers

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#52,214 opened on Jan 29, 2019

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Description
Previous ID SR-9789
Radar None
Original Reporter @belkadan
Type Improvement
Votes 0
Component/s Compiler
Labels Improvement, PrintAsObjC, StarterBug
Assignee @adellibovi
Priority Medium

md5: 0bc925759fd7590c0a91c67c7a5de68f

Issue Description:

Objective-C supports two "pretty" forms for nullability qualifiers: within the parentheses of a method's parameters or return type:

- (id _Nullable)computate:(int * _Nonnull)values;

- (nullable id)computate:(nonnull int *)values;

And in the property attributes list for a property:

@property id _Nullable owner;

@property (nullable) id owner;

PrintAsObjC should adopt these where valid; right now it only uses them in hardcoded cases for instancetype.

Contributor guide

Research direction
Look at the PrintAsObjC implementation in the Swift compiler, locate where nullability qualifiers are emitted, and update them to use the 'pretty' forms like `nullable` and `nonnull` inside parentheses or property attributes. Start by examining the existing hardcoded usage for `instancetype`.
Tech stack
swiftobjective c
Domain
compilers
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GitSwift
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
80