Fix explicit_type_interface when used in statements

CHANGELOG.md

@@ -85,6 +85,10 @@
 
 #### Bug Fixes
 
+* Fix `explicit_type_interface` when used in statements.  
+  [Daniel Metzing](https://github.com/dirtydanee)
+  [#2154](https://github.com/realm/SwiftLint/issues/2154)
+
 * Fix an issue with `control_statement` where commas in clauses prevented the
   rule from applying.  
   [Allen Wu](https://github.com/allewun)

Source/SwiftLintFramework/Rules/Idiomatic/ExplicitTypeInterfaceRule.swift

@@ -1,11 +1,30 @@
 import Foundation
 import SourceKittenFramework
 
-public struct ExplicitTypeInterfaceRule: ASTRule, OptInRule, ConfigurationProviderRule {
+private typealias DeclarationKindWithMetadata = (declarationKind: SwiftDeclarationKind,
+                                                 dictionary: [String: SourceKitRepresentable],
+                                                 parentDictionary: [String: SourceKitRepresentable])
+
+public struct ExplicitTypeInterfaceRule: OptInRule, ConfigurationProviderRule {
+
     public var configuration = ExplicitTypeInterfaceConfiguration()
 
     public init() {}
 
+    fileprivate static let captureGroupPattern =
+    "\\{"       + // The { character
+    "\\s*"      + // Zero or more whitespace character(s)
+    "\\["       + // The [ characterassociatedEnum
+    "("         + // Start if the first capturing group
+    "\\s*"      + // Zero or more whitespace character(s)
+    "\\w+"      + // At least one word character
+    "\\s+"      + // At least one whitespace character
+    "\\w+"      + // At least one world character
+    ",*"        + // Zero or more , character
+    ")"         + // End of the first capturing group
+    "+"         + // At least occurance of the first capturing group
+    "\\]"         // The ] character
+
     public static let description = RuleDescription(
         identifier: "explicit_type_interface",
         name: "Explicit Type Interface",
@@ -27,39 +46,130 @@ public struct ExplicitTypeInterfaceRule: ASTRule, OptInRule, ConfigurationProvid
         ]
     )
 
-    public func validate(file: File, kind: SwiftDeclarationKind,
-                         dictionary: [String: SourceKitRepresentable]) -> [StyleViolation] {
+    public func validate(file: File) -> [StyleViolation] {
 
-        guard configuration.allowedKinds.contains(kind),
-            !containsType(dictionary: dictionary),
-            (!configuration.allowRedundancy || !assigneeIsInitCall(file: file, dictionary: dictionary)),
-            let offset = dictionary.offset else {
-                return []
+        let captureGroupByteRanges = file.captureGroupByteRanges
+        let elements = file.dictionaries(of: configuration.allowedKinds)
+
+        return elements.compactMap { element -> StyleViolation? in
+            guard !element.dictionary.containsType,
+                  let offset = element.dictionary.offset,
+                  (!configuration.allowRedundancy || !element.dictionary.isInitCall(file: file)),
+                  !element.parentDictionary.contains([.forEach, .guard]),
+                  !element.parentDictionary.caseStatementPatternRanges.contains(offset),
+                  !element.parentDictionary.caseExpressionRanges.contains(offset),
+                  !captureGroupByteRanges.contains(offset) else {
+                    return nil
+            }
+
+            return StyleViolation(ruleDescription: type(of: self).description,
+                                  severity: configuration.severityConfiguration.severity,
+                                  location: Location(file: file, byteOffset: offset))
         }
+    }
+}
 
-        return [
-            StyleViolation(ruleDescription: type(of: self).description,
-                           severity: configuration.severityConfiguration.severity,
-                           location: Location(file: file, byteOffset: offset))
-        ]
+private extension File {
+
+    var captureGroupByteRanges: [NSRange] {
+        return match(pattern: ExplicitTypeInterfaceRule.captureGroupPattern,
+                     excludingSyntaxKinds: SyntaxKind.commentKinds)
+            .compactMap { contents.bridge().NSRangeToByteRange(start: $0.location, length: $0.length) }
+    }
+
+    func dictionaries(of declarationKinds: Set<SwiftDeclarationKind>) -> [DeclarationKindWithMetadata] {
+        var declarations = [DeclarationKindWithMetadata]()
+        func search(in dictionary: [String: SourceKitRepresentable], parent: [String: SourceKitRepresentable]) {
+            if let kind = dictionary.kind,
+                let declarationKind = SwiftDeclarationKind(rawValue: kind),
+                declarationKinds.contains(declarationKind) {
+                declarations.append((declarationKind,
+                                    dictionary,
+                                    parent))
+            }
+
+            dictionary.substructure.forEach { search(in: $0, parent: dictionary) }
+        }
+
+        search(in: structure.dictionary, parent: [:])
+        return declarations
+    }
+}
+
+private extension Dictionary where Key == String, Value == SourceKitRepresentable {
+    var containsType: Bool {
+        return typeName != nil
     }
 
-    private func containsType(dictionary: [String: SourceKitRepresentable]) -> Bool {
-        return dictionary.typeName != nil
+    var caseStatementPatternRanges: [NSRange] {
+        return ranges(with: StatementKind.case.rawValue, for: "source.lang.swift.structure.elem.pattern")
     }
 
-    private func assigneeIsInitCall(file: File, dictionary: [String: SourceKitRepresentable]) -> Bool {
+    var caseExpressionRanges: [NSRange] {
+        return ranges(with: "source.lang.swift.expr.tuple", for: "source.lang.swift.structure.elem.expr")
+    }
+
+    func isInitCall(file: File) -> Bool {
         guard
-            let nameOffset = dictionary.nameOffset,
-            let nameLength = dictionary.nameLength,
-            let afterNameRange = file.contents.bridge().byteRangeToNSRange(start: nameOffset + nameLength, length: 0)
-        else {
-            return false
+            let nameOffset = nameOffset,
+            let nameLength = nameLength,
+            case let contents = file.contents.bridge(),
+            let afterNameRange = contents.byteRangeToNSRange(start: nameOffset + nameLength, length: 0)
+            else {
+                return false
         }
 
-        let contentAfterName = file.contents.bridge().substring(from: afterNameRange.location)
+        let contentAfterName = contents.substring(from: afterNameRange.location)
         let initCallRegex = regex("^\\s*=\\s*\\p{Lu}[^\\(\\s<]*(?:<[^\\>]*>)?\\(")
 
         return initCallRegex.firstMatch(in: contentAfterName, options: [], range: contentAfterName.fullNSRange) != nil
     }
+
+    func contains(_ statements: Set<StatementKind>) -> Bool {
+        return StatementKind(optionalRawValue: kind).isKind(of: statements)
+    }
+
+    func ranges(with parentKind: String, for elementKind: String) -> [NSRange] {
+        guard parentKind == kind else {
+            return []
+        }
+
+        return elements.filter { elementKind == $0.kind }
+                       .compactMap { NSRange(location: $0.offset, length: $0.length) }
+    }
+}
+
+private extension Optional where Wrapped == StatementKind {
+    func isKind(of statements: Set<StatementKind>) -> Bool {
+        guard let stmt = self else {
+            return false
+        }
+        return statements.contains(stmt)
+    }
+}
+
+private extension StatementKind {
+    init?(optionalRawValue: String?) {
+        guard let rawValue = optionalRawValue,
+              let stmt = StatementKind(rawValue: rawValue) else {
+            return nil
+        }
+        self = stmt
+    }
+}
+
+private extension NSRange {
+    init?(location: Int?, length: Int?) {
+        guard let location = location, let length = length else {
+            return nil
+        }
+
+        self = NSRange(location: location, length: length)
+    }
+}
+
+private extension Collection where Element == NSRange {
+    func contains(_ index: Int) -> Bool {
+        return first(where: { $0.contains(index) }) != nil
+    }
 }

Tests/LinuxMain.swift

@@ -354,7 +354,11 @@ extension ExplicitTypeInterfaceRuleTests {
         ("testExplicitTypeInterface", testExplicitTypeInterface),
         ("testExcludeLocalVars", testExcludeLocalVars),
         ("testExcludeClassVars", testExcludeClassVars),
-        ("testAllowRedundancy", testAllowRedundancy)
+        ("testAllowRedundancy", testAllowRedundancy),
+        ("testEmbededInStatements", testEmbededInStatements),
+        ("testCaptureGroup", testCaptureGroup),
+        ("testFastEnumerationDeclaration", testFastEnumerationDeclaration),
+        ("testSwitchCaseDeclarations", testSwitchCaseDeclarations)
     ]
 }
 

Tests/SwiftLintFrameworkTests/ExplicitTypeInterfaceRuleTests.swift

@@ -52,10 +52,132 @@ class ExplicitTypeInterfaceRuleTests: XCTestCase {
             "class Foo {\n  ↓static var myStaticVar = 0\n}\n",
             "class Foo {\n  ↓class var myClassVar = 0\n}\n"
         ]
+
         let description = ExplicitTypeInterfaceRule.description
             .with(triggeringExamples: triggeringExamples)
             .with(nonTriggeringExamples: nonTriggeringExamples)
 
         verifyRule(description, ruleConfiguration: ["allow_redundancy": true])
     }
+
+    func testEmbededInStatements() {
+        let nonTriggeringExamples = [
+            "func foo() {\n"                        +
+            "   var bar: String?\n"                 +
+            "   guard let strongBar = bar else {\n" +
+            "       return\n"                       +
+            "   }\n"                                +
+            "}",
+            "struct SomeError: Error {}\n"          +
+                "var error: Error?\n"               +
+                "switch error {\n"                  +
+                "case let error as SomeError:\n"    +
+                "   break\n"                        +
+                "default:\n"                        +
+                "   break\n"                        +
+            "}"
+        ]
+        let triggeringExamples = ExplicitTypeInterfaceRule.description.triggeringExamples
+        let description = ExplicitTypeInterfaceRule.description
+            .with(triggeringExamples: triggeringExamples)
+            .with(nonTriggeringExamples: nonTriggeringExamples)
+
+        verifyRule(description)
+    }
+
+    func testCaptureGroup() {
+        let nonTriggeringExamples = [
+            "var k: Int = 0\n"                                          +
+                "_ = { [weak k] in\n"                                   +
+                "       print(k)\n"                                     +
+            "   }",
+            "var k: Int = 0\n"                                          +
+                "_ = { [unowned k] in\n"                                +
+                "       print(k)\n"                                     +
+            "   }",
+            "class Foo {\n"                                             +
+                "   func bar() {\n"                                     +
+                "       var k: Int = 0\n"                               +
+                "       _ = { [weak self, weak k] in\n"                 +
+                "       guard let strongSelf = self else { return }\n"  +
+                "       }\n"                                            +
+                "   }\n"    +
+            "}"
+        ]
+        let triggeringExamples = ExplicitTypeInterfaceRule.description.triggeringExamples
+        let description = ExplicitTypeInterfaceRule.description
+            .with(triggeringExamples: triggeringExamples)
+            .with(nonTriggeringExamples: nonTriggeringExamples)
+
+        verifyRule(description)
+    }
+
+    func testFastEnumerationDeclaration() {
+        let nonTriggeringExaples = [
+            "func foo() {\n"                                        +
+            "   let elements: [Int] = [1, 2]\n"                     +
+            "   for element in elements {}\n"                       +
+            "}",
+            "func foo() {\n"                                        +
+            "   let elements: [Int] = [1, 2]\n"                     +
+            "   for (index, element) in elements.enumerated() {}\n" +
+            "}\n"
+        ]
+
+        let triggeringExamples = ExplicitTypeInterfaceRule.description.triggeringExamples
+        let description = ExplicitTypeInterfaceRule.description
+            .with(triggeringExamples: triggeringExamples)
+            .with(nonTriggeringExamples: nonTriggeringExaples)
+        verifyRule(description)
+    }
+
+    func testSwitchCaseDeclarations() {
+
+        guard SwiftVersion.current >= .fourDotOne else {
+            return
+        }
+
+        let nonTriggeringExamples: [String] = [
+            "enum Foo {\n"                                      +
+            "   case failure(Any)\n"                            +
+            "   case success(Any)\n"                            +
+            "}\n"                                               +
+            "func bar() {\n"                                      +
+            "   let foo: Foo = Foo.success(1)\n"                +
+            "   switch foo {\n"                                 +
+            "   case .failure(let error): let bar: Int = 1\n"   +
+            "   case .success(let result): let bar: Int = 2\n"  +
+            "   }\n"                                            +
+            "}",
+            "func foo() {\n"                                    +
+            "   switch foo {\n"                                 +
+            "   case var (x, y): break\n"                       +
+            "   }\n"                                            +
+            "}"
+        ]
+
+        let triggeringExamples = [
+            "enum Foo {\n"                                      +
+            "   case failure(Any)\n"                            +
+            "   case success(Any, Any)\n"                       +
+            "}\n"                                               +
+            "func bar {\n"                                      +
+            "   let foo: Foo = Foo.success(1)\n"                +
+            "   switch foo {\n"                                 +
+            "   case .failure(let foo): ↓let fooBar = 1\n"      +
+            "   case let .success(foo, bar): ↓let fooBar = 1\n" +
+            "   }\n"                                            +
+            "}",
+            "func foo() {\n"                                   +
+            "   switch foo {\n"                                +
+            "   case var (x, y): ↓let fooBar = 1\n"            +
+            "   }\n"                                           +
+            "}"
+        ]
+
+        let description = ExplicitTypeInterfaceRule.description
+            .with(triggeringExamples: triggeringExamples)
+            .with(nonTriggeringExamples: nonTriggeringExamples)
+        verifyRule(description)
+    }
 }