swiftlang/swift

[SR-4824] Add tests to check Collection constraints are being enforced

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#47,401 opened on May 7, 2017

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Description
Previous ID SR-4824
Radar rdar://problem/32134714
Original Reporter @airspeedswift
Type Bug
Votes 0
Component/s Standard Library
Labels Bug, StarterBug
Assignee djwbrown (JIRA)
Priority Medium

md5: 6b6aabc9be01be2d9974ed98c3c057f8

Issue Description:

https://github.com/apple/swift/pull/9379 removed tests confirming collection's associated types conformed to appropriate protocols e.g. MutableCollection.SubSequence: MutableCollection. Now the compiler is enforcing these, so they were just generating warnings.

They should be replaced by tests checking the compiler is enforcing these rules (by trying to create invalid collections and checking the error messages).

Contributor guide

Tech stack
swift
Domain
testing
Issue type
test
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 basicscollection protocols
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Look at the tests removed in PR #9379 to understand what they validated. Then, create new tests that attempt to define invalid collection types and check the compiler's error messages. Use existing test files as a guide for how to structure tests that expect compiler errors.