91 lines
3.5 KiB
Swift
91 lines
3.5 KiB
Swift
import SwiftSyntax
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struct UnusedEnumeratedRule: SwiftSyntaxRule, ConfigurationProviderRule {
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var configuration = SeverityConfiguration(.warning)
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init() {}
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static let description = RuleDescription(
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identifier: "unused_enumerated",
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name: "Unused Enumerated",
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description: "When the index or the item is not used, `.enumerated()` can be removed.",
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kind: .idiomatic,
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nonTriggeringExamples: [
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Example("for (idx, foo) in bar.enumerated() { }\n"),
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Example("for (_, foo) in bar.enumerated().something() { }\n"),
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Example("for (_, foo) in bar.something() { }\n"),
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Example("for foo in bar.enumerated() { }\n"),
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Example("for foo in bar { }\n"),
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Example("for (idx, _) in bar.enumerated().something() { }\n"),
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Example("for (idx, _) in bar.something() { }\n"),
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Example("for idx in bar.indices { }\n"),
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Example("for (section, (event, _)) in data.enumerated() {}\n")
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],
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triggeringExamples: [
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Example("for (↓_, foo) in bar.enumerated() { }\n"),
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Example("for (↓_, foo) in abc.bar.enumerated() { }\n"),
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Example("for (↓_, foo) in abc.something().enumerated() { }\n"),
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Example("for (idx, ↓_) in bar.enumerated() { }\n")
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]
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)
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func makeVisitor(file: SwiftLintFile) -> ViolationsSyntaxVisitor {
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Visitor(viewMode: .sourceAccurate)
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}
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}
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private extension UnusedEnumeratedRule {
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final class Visitor: ViolationsSyntaxVisitor {
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override func visitPost(_ node: ForInStmtSyntax) {
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guard let tuplePattern = node.pattern.as(TuplePatternSyntax.self),
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tuplePattern.elements.count == 2,
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let functionCall = node.sequenceExpr.asFunctionCall,
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functionCall.isEnumerated,
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let firstElement = tuplePattern.elements.first,
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let secondElement = tuplePattern.elements.last,
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case let firstTokenIsUnderscore = firstElement.isUnderscore,
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case let lastTokenIsUnderscore = secondElement.isUnderscore,
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firstTokenIsUnderscore || lastTokenIsUnderscore else {
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return
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}
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let position: AbsolutePosition
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let reason: String
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if firstTokenIsUnderscore {
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position = firstElement.positionAfterSkippingLeadingTrivia
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reason = "When the index is not used, `.enumerated()` can be removed"
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} else {
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position = secondElement.positionAfterSkippingLeadingTrivia
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reason = "When the item is not used, `.indices` should be used instead of `.enumerated()`"
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}
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violations.append(ReasonedRuleViolation(position: position, reason: reason))
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}
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}
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}
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private extension FunctionCallExprSyntax {
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var isEnumerated: Bool {
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guard let memberAccess = calledExpression.as(MemberAccessExprSyntax.self),
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memberAccess.base != nil,
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memberAccess.name.withoutTrivia().text == "enumerated",
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hasNoArguments else {
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return false
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}
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return true
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}
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var hasNoArguments: Bool {
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trailingClosure == nil &&
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(additionalTrailingClosures?.isEmpty ?? true) &&
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argumentList.isEmpty
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}
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}
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private extension TuplePatternElementSyntax {
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var isUnderscore: Bool {
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pattern.is(WildcardPatternSyntax.self)
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}
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}
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