swiftlang/swift

`[.]Type` completion for `(any P).` shows it will produce an existential metatype

Open

#65,843 opened on May 10, 2023

View on GitHub
 (32 comments) (0 reactions) (0 assignees)Swift (10,719 forks)batch import
bugcode completionexistentialsgood first issuemetatypessource toolingswift 5.9typesunexpected behavior

Repository metrics

Stars
 (69,989 stars)
PR merge metrics
 (Avg merge 8d 17h) (510 merged PRs in 30d)

Description

Test case:

// RUN: %empty-directory(%t)
// RUN: %target-swift-ide-test -batch-code-completion -source-filename %s -filecheck %raw-FileCheck -completion-output-dir %t
protocol P {}

(any P).#^COMPLETE?check=META^# 
// META: Keyword/CurrNominal:  Type[#(any P).Type#]; name=Type

This test will fail, because the current completion is Type[#any P.Type#]; name=Type. Notice how it thinks the completion will produce an existential metatype any P.Type, whereas the actual result is the singleton metatype (any P).Type.

Note any syntax was proposed in SE-0335.

Environment

  • Swift 5.9-dev (c1d5118c21da49a9c2194734cbf9b6970bc63056)

Contributor guide

Research direction
Investigate the code completion logic for existential types, specifically how the type '(any P).Type' is computed and why it returns 'any P.Type' instead.
Tech stack
swift
Domain
developer experience
Issue type
Bug
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
Swift
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60