From a4fbb6622b77cd3f7db70ca1e1012b79c4a81720 Mon Sep 17 00:00:00 2001
From: Blake <>
Date: Thu, 13 Feb 2020 01:30:27 -0600
Subject: [PATCH] Adding Legacy ObjC Type Rule #2758

---
 CHANGELOG.md                                  |  8 +++
 .../Models/PrimaryRuleList.swift              |  1 +
 .../Rules/Idiomatic/LegacyObjcTypeRule.swift  | 63 +++++++++++++++++++
 Tests/LinuxMain.swift                         |  7 +++
 .../AutomaticRuleTests.generated.swift        |  6 ++
 5 files changed, 85 insertions(+)
 create mode 100644 Source/SwiftLintFramework/Rules/Idiomatic/LegacyObjcTypeRule.swift

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 49d2c7f76d..9b8a779136 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -46,6 +46,14 @@
   explicitly referenced by other code.  
   [JP Simard](https://github.com/jpsim)
 
+* Make `strong_iboutlet` rule correctable.  
+  [MaxHaertwig](https://github.com/maxhaertwig)
+
+* Add `legacy_objc_type` opt-in rule to warn against using
+  bridged Objective-C reference types instead of Swift value types.  
+  [Blake](https://github.com/72A12F4E)
+  [#2758](https://github.com/realm/SwiftLint/issues/2758)
+
 #### Bug Fixes
 
 * Fix typos in configuration options for `file_name` rule.  
diff --git a/Source/SwiftLintFramework/Models/PrimaryRuleList.swift b/Source/SwiftLintFramework/Models/PrimaryRuleList.swift
index 27ad435a07..0864a76da9 100644
--- a/Source/SwiftLintFramework/Models/PrimaryRuleList.swift
+++ b/Source/SwiftLintFramework/Models/PrimaryRuleList.swift
@@ -91,6 +91,7 @@ public let primaryRuleList = RuleList(rules: [
     LegacyHashingRule.self,
     LegacyMultipleRule.self,
     LegacyNSGeometryFunctionsRule.self,
+    LegacyObjcTypeRule.self,
     LegacyRandomRule.self,
     LetVarWhitespaceRule.self,
     LineLengthRule.self,
diff --git a/Source/SwiftLintFramework/Rules/Idiomatic/LegacyObjcTypeRule.swift b/Source/SwiftLintFramework/Rules/Idiomatic/LegacyObjcTypeRule.swift
new file mode 100644
index 0000000000..cd298914ed
--- /dev/null
+++ b/Source/SwiftLintFramework/Rules/Idiomatic/LegacyObjcTypeRule.swift
@@ -0,0 +1,63 @@
+import Foundation
+import SourceKittenFramework
+
+private let legacyObjcTypes = [
+    "NSAffineTransform",
+    "NSArray",
+    "NSCalendar",
+    "NSCharacterSet",
+    "NSData",
+    "NSDateComponents",
+    "NSDateInterval",
+    "NSDate",
+    "NSDecimalNumber",
+    "NSDictionary",
+    "NSIndexPath",
+    "NSIndexSet",
+    "NSLocale",
+    "NSMeasurement",
+    "NSNotification",
+    "NSNumber",
+    "NSPersonNameComponents",
+    "NSSet",
+    "NSString",
+    "NSTimeZone",
+    "NSURL",
+    "NSURLComponents",
+    "NSURLQueryItem",
+    "NSURLRequest",
+    "NSUUID"
+]
+
+public struct LegacyObjcTypeRule: OptInRule, ConfigurationProviderRule, AutomaticTestableRule {
+    public var configuration = SeverityConfiguration(.warning)
+
+    public init() {}
+
+    public static let description = RuleDescription(
+        identifier: "legacy_objc_type",
+        name: "Legacy Objective-C Reference Type",
+        description: "Prefer Swift value types to bridged Objective-C reference types",
+        kind: .idiomatic,
+        nonTriggeringExamples: [
+            Example("var array = Array<Int>()\n"),
+            Example("var calendar: Calendar? = nil")
+        ],
+        triggeringExamples: [
+            Example("var array = NSArray()"),
+            Example("var calendar: NSCalendar? = nil")
+        ]
+    )
+
+    private let pattern = legacyObjcTypes.joined(separator: "|")
+
+    public func validate(file: SwiftLintFile) -> [StyleViolation] {
+        return file.match(pattern: pattern)
+            .filter { !Set($0.1).isDisjoint(with: [.typeidentifier, .identifier]) }
+            .map {
+                StyleViolation(ruleDescription: Self.description,
+                               severity: configuration.severity,
+                               location: Location(file: file, characterOffset: $0.0.location))
+            }
+    }
+}
diff --git a/Tests/LinuxMain.swift b/Tests/LinuxMain.swift
index 6c111536f1..c4febefede 100644
--- a/Tests/LinuxMain.swift
+++ b/Tests/LinuxMain.swift
@@ -858,6 +858,12 @@ extension LegacyNSGeometryFunctionsRuleTests {
     ]
 }
 
+extension LegacyObjcTypeRuleTests {
+    static var allTests: [(String, (LegacyObjcTypeRuleTests) -> () throws -> Void)] = [
+        ("testWithDefaultConfiguration", testWithDefaultConfiguration)
+    ]
+}
+
 extension LegacyRandomRuleTests {
     static var allTests: [(String, (LegacyRandomRuleTests) -> () throws -> Void)] = [
         ("testWithDefaultConfiguration", testWithDefaultConfiguration)
@@ -1878,6 +1884,7 @@ XCTMain([
     testCase(LegacyHashingRuleTests.allTests),
     testCase(LegacyMultipleRuleTests.allTests),
     testCase(LegacyNSGeometryFunctionsRuleTests.allTests),
+    testCase(LegacyObjcTypeRuleTests.allTests),
     testCase(LegacyRandomRuleTests.allTests),
     testCase(LetVarWhitespaceRuleTests.allTests),
     testCase(LineEndingTests.allTests),
diff --git a/Tests/SwiftLintFrameworkTests/AutomaticRuleTests.generated.swift b/Tests/SwiftLintFrameworkTests/AutomaticRuleTests.generated.swift
index 937db6c1b1..3f44064e21 100644
--- a/Tests/SwiftLintFrameworkTests/AutomaticRuleTests.generated.swift
+++ b/Tests/SwiftLintFrameworkTests/AutomaticRuleTests.generated.swift
@@ -360,6 +360,12 @@ class LegacyNSGeometryFunctionsRuleTests: XCTestCase {
     }
 }
 
+class LegacyObjcTypeRuleTests: XCTestCase {
+    func testWithDefaultConfiguration() {
+        verifyRule(LegacyObjcTypeRule.description)
+    }
+}
+
 class LegacyRandomRuleTests: XCTestCase {
     func testWithDefaultConfiguration() {
         verifyRule(LegacyRandomRule.description)