swiftlang/swift

[SR-1807] Sema should catch and warn about self capture in closures

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#44,416 opened on Jun 17, 2016

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Description
Previous ID SR-1807
Radar rdar://26865978
Original Reporter @CodaFi
Type New Feature
Votes 0
Component/s Compiler
Labels New Feature, StarterBug
Assignee None
Priority Medium

md5: 3ea294e377274fa3d27e3c3b76ff7bbd

Issue Description:

To maintain parity with Objective-C, we should use our ARC analysis pass in Sema to check for the presence of self capture in blocks without weak or @noescape. This should be a very simple warning modeled after the one in /clang/lib/Sema/SemaChecking.cpp void diagnoseRetainCycle().

Contributor guide

Research direction
Study the existing Clang diagnoseRetainCycle function and implement a similar warning in Swift's Sema ARC analysis pass for self capture in closures without weak or @noescape.
Tech stack
swift
Domain
tooling
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.
1-2 days
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
SwiftCompiler Design
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60