Adds opt-in discouraged_object_literal rule

Implements realm#1987.

CHANGELOG.md

@@ -20,6 +20,11 @@
   [Daniel Metzing](https://github.com/dirtydanee)
   [#1924](https://github.com/realm/SwiftLint/issues/1924)
 
+* Add `discouraged_object_literal` opt-in rule which encourages initializers
+  over object literals.  
+  [Ornithologist Coder](https://github.com/ornithocoder)
+  [#1987](https://github.com/realm/SwiftLint/issues/1987)
+
 ##### Bug Fixes
 
 * Fix false positives in `control_statement` rule when methods with keyword

Rules.md

@@ -19,6 +19,7 @@
 * [Cyclomatic Complexity](#cyclomatic-complexity)
 * [Discarded Notification Center Observer](#discarded-notification-center-observer)
 * [Discouraged Direct Initialization](#discouraged-direct-initialization)
+* [Discouraged Object Literal](#discouraged-object-literal)
 * [Dynamic Inline](#dynamic-inline)
 * [Empty Count](#empty-count)
 * [Empty Enum Arguments](#empty-enum-arguments)
@@ -2066,6 +2067,59 @@ let foo = bar(bundle: ↓Bundle.init(), device: ↓UIDevice.init())
 
 
 
+## Discouraged Object Literal
+
+Identifier | Enabled by default | Supports autocorrection | Kind 
+--- | --- | --- | ---
+`discouraged_object_literal` | Disabled | No | idiomatic
+
+Prefer initializers over object literals.
+
+### Examples
+
+<details>
+<summary>Non Triggering Examples</summary>
+
+```swift
+let image = UIImage(named: aVariable)
+```
+
+```swift
+let image = UIImage(named: "interpolated \(variable)")
+```
+
+```swift
+let color = UIColor(red: value, green: value, blue: value, alpha: 1)
+```
+
+```swift
+let image = NSImage(named: aVariable)
+```
+
+```swift
+let image = NSImage(named: "interpolated \(variable)")
+```
+
+```swift
+let color = NSColor(red: value, green: value, blue: value, alpha: 1)
+```
+
+</details>
+<details>
+<summary>Triggering Examples</summary>
+
+```swift
+let image = ↓#imageLiteral(resourceName: "image.jpg")
+```
+
+```swift
+let color = ↓#colorLiteral(red: 0.9607843161, green: 0.7058823705, blue: 0.200000003, alpha: 1)
+```
+
+</details>
+
+
+
 ## Dynamic Inline
 
 Identifier | Enabled by default | Supports autocorrection | Kind 

Source/SwiftLintFramework/Models/MasterRuleList.swift

@@ -27,6 +27,7 @@ public let masterRuleList = RuleList(rules: [
     CyclomaticComplexityRule.self,
     DiscardedNotificationCenterObserverRule.self,
     DiscouragedDirectInitRule.self,
+    DiscouragedObjectLiteralRule.self,
     DynamicInlineRule.self,
     EmptyCountRule.self,
     EmptyEnumArgumentsRule.self,

Source/SwiftLintFramework/Rules/DiscouragedObjectLiteralRule.swift

@@ -0,0 +1,45 @@
+//
+//  DiscouragedObjectLiteralRule.swift
+//  SwiftLint
+//
+//  Created by Ornithologist Coder on 1/3/18.
+//  Copyright © 2018 Realm. All rights reserved.
+//
+
+import Foundation
+import SourceKittenFramework
+
+public struct DiscouragedObjectLiteralRule: ASTRule, OptInRule, ConfigurationProviderRule {
+    public var configuration = SeverityConfiguration(.warning)
+
+    public init() {}
+
+    public static let description = RuleDescription(
+        identifier: "discouraged_object_literal",
+        name: "Discouraged Object Literal",
+        description: "Prefer initializers over object literals.",
+        kind: .idiomatic,
+        nonTriggeringExamples: [
+            "let image = UIImage(named: aVariable)",
+            "let image = UIImage(named: \"interpolated \\(variable)\")",
+            "let color = UIColor(red: value, green: value, blue: value, alpha: 1)",
+            "let image = NSImage(named: aVariable)",
+            "let image = NSImage(named: \"interpolated \\(variable)\")",
+            "let color = NSColor(red: value, green: value, blue: value, alpha: 1)"
+        ],
+        triggeringExamples: [
+            "let image = ↓#imageLiteral(resourceName: \"image.jpg\")",
+            "let color = ↓#colorLiteral(red: 0.9607843161, green: 0.7058823705, blue: 0.200000003, alpha: 1)"
+        ]
+    )
+
+    public func validate(file: File,
+                         kind: SwiftExpressionKind,
+                         dictionary: [String: SourceKitRepresentable]) -> [StyleViolation] {
+        guard let offset = dictionary.offset, kind == .objectLiteral else { return [] }
+
+        return [StyleViolation(ruleDescription: type(of: self).description,
+                               severity: configuration.severity,
+                               location: Location(file: file, byteOffset: offset))]
+    }
+}

SwiftLint.xcodeproj/project.pbxproj

@@ -75,6 +75,7 @@
 		623E36F01F3DB1B1002E5B71 /* QuickDiscouragedCallRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 623E36EF1F3DB1B1002E5B71 /* QuickDiscouragedCallRule.swift */; };
 		623E36F21F3DB988002E5B71 /* QuickDiscouragedCallRuleExamples.swift in Sources */ = {isa = PBXBuildFile; fileRef = 623E36F11F3DB988002E5B71 /* QuickDiscouragedCallRuleExamples.swift */; };
 		6250D32A1ED4DFEB00735129 /* MultilineParametersRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6238AE411ED4D734006C3601 /* MultilineParametersRule.swift */; };
+		6258783B1FFC458100AC34F2 /* DiscouragedObjectLiteralRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6258783A1FFC458100AC34F2 /* DiscouragedObjectLiteralRule.swift */; };
 		62622F6B1F2F2E3500D5D099 /* DiscouragedDirectInitRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 62622F6A1F2F2E3500D5D099 /* DiscouragedDirectInitRule.swift */; };
 		626C16E21F948EBC00BB7475 /* QuickDiscouragedFocusedTestRuleExamples.swift in Sources */ = {isa = PBXBuildFile; fileRef = 626C16E01F948E1C00BB7475 /* QuickDiscouragedFocusedTestRuleExamples.swift */; };
 		626D02971F31CBCC0054788D /* XCTFailMessageRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 626D02961F31CBCC0054788D /* XCTFailMessageRule.swift */; };
@@ -417,6 +418,7 @@
 		6238AE411ED4D734006C3601 /* MultilineParametersRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MultilineParametersRule.swift; sourceTree = "<group>"; };
 		623E36EF1F3DB1B1002E5B71 /* QuickDiscouragedCallRule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = QuickDiscouragedCallRule.swift; sourceTree = "<group>"; };
 		623E36F11F3DB988002E5B71 /* QuickDiscouragedCallRuleExamples.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = QuickDiscouragedCallRuleExamples.swift; sourceTree = "<group>"; };
+		6258783A1FFC458100AC34F2 /* DiscouragedObjectLiteralRule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DiscouragedObjectLiteralRule.swift; sourceTree = "<group>"; };
 		62622F6A1F2F2E3500D5D099 /* DiscouragedDirectInitRule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DiscouragedDirectInitRule.swift; sourceTree = "<group>"; };
 		626C16E01F948E1C00BB7475 /* QuickDiscouragedFocusedTestRuleExamples.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = QuickDiscouragedFocusedTestRuleExamples.swift; sourceTree = "<group>"; };
 		626D02961F31CBCC0054788D /* XCTFailMessageRule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCTFailMessageRule.swift; sourceTree = "<group>"; };
@@ -1017,6 +1019,7 @@
 				2E02005E1C54BF680024D09D /* CyclomaticComplexityRule.swift */,
 				D4DABFD21E29B4A5009617B6 /* DiscardedNotificationCenterObserverRule.swift */,
 				62622F6A1F2F2E3500D5D099 /* DiscouragedDirectInitRule.swift */,
+				6258783A1FFC458100AC34F2 /* DiscouragedObjectLiteralRule.swift */,
 				E315B83B1DFA4BC500621B44 /* DynamicInlineRule.swift */,
 				E847F0A81BFBBABD00EA9363 /* EmptyCountRule.swift */,
 				D4470D581EB6B4D1008A1B2E /* EmptyEnumArgumentsRule.swift */,
@@ -1473,6 +1476,7 @@
 				BFF028AE1CBCF8A500B38A9D /* TrailingWhitespaceConfiguration.swift in Sources */,
 				3B034B6E1E0BE549005D49A9 /* LineLengthConfiguration.swift in Sources */,
 				B25DCD0C1F7E9FA20028A199 /* MultilineArgumentsRule.swift in Sources */,
+				6258783B1FFC458100AC34F2 /* DiscouragedObjectLiteralRule.swift in Sources */,
 				D4C4A34C1DEA4FF000E0E04C /* AttributesConfiguration.swift in Sources */,
 				83D71E281B131ECE000395DE /* RuleDescription.swift in Sources */,
 				D4470D571EB69225008A1B2E /* ImplicitReturnRule.swift in Sources */,

Tests/LinuxMain.swift

@@ -371,6 +371,7 @@ extension RulesTests {
         ("testControlStatement", testControlStatement),
         ("testCyclomaticComplexity", testCyclomaticComplexity),
         ("testDiscardedNotificationCenterObserver", testDiscardedNotificationCenterObserver),
+        ("testDiscouragedObjectLiteralRule", testDiscouragedObjectLiteralRule),
         ("testDynamicInline", testDynamicInline),
         ("testEmptyCount", testEmptyCount),
         ("testEmptyEnumArguments", testEmptyEnumArguments),

Tests/SwiftLintFrameworkTests/RulesTests.swift

@@ -70,6 +70,10 @@ class RulesTests: XCTestCase {
         verifyRule(DiscardedNotificationCenterObserverRule.description)
     }
 
+    func testDiscouragedObjectLiteralRule() {
+        verifyRule(DiscouragedObjectLiteralRule.description)
+    }
+
     func testDynamicInline() {
         verifyRule(DynamicInlineRule.description)
     }