Ignore MARK in multiline comment

Fixes realm#1749 and realm#3841

Source/SwiftLintFramework/Rules/Lint/MarkRule.swift

@@ -9,15 +9,16 @@ public struct MarkRule: CorrectableRule, ConfigurationProviderRule {
     public static let description = RuleDescription(
         identifier: "mark",
         name: "Mark",
-        description: "MARK comment should be in valid format. e.g. '// MARK: ...' or '// MARK: - ...'",
+        description: "MARK comment should be in valid format. e.g. '// MARK: ...' or '// MARK: - ...'; MARK in multiline comments will be ignored.",
         kind: .lint,
         nonTriggeringExamples: [
             Example("// MARK: good\n"),
             Example("// MARK: - good\n"),
             Example("// MARK: -\n"),
             Example("// BOOKMARK"),
             Example("//BOOKMARK"),
-            Example("// BOOKMARKS")
+            Example("// BOOKMARKS"),
+            issue1749Example
         ],
         triggeringExamples: [
             Example("↓//MARK: bad"),
@@ -64,7 +65,8 @@ public struct MarkRule: CorrectableRule, ConfigurationProviderRule {
             Example("↓// MARKK -"): Example("// MARK: -"),
             Example("↓/// MARK:"): Example("// MARK:"),
             Example("↓/// MARK comment"): Example("// MARK: comment"),
-            issue1029Example: issue1029Correction
+            issue1029Example: issue1029Correction,
+            issue1749Example: issue1749Correction
         ]
     )
 
@@ -183,11 +185,20 @@ public struct MarkRule: CorrectableRule, ConfigurationProviderRule {
     }
 
     private func violationRanges(in file: SwiftLintFile, matching pattern: String) -> [NSRange] {
-        return file.rangesAndTokens(matching: pattern).filter { _, syntaxTokens in
-            guard let syntaxKind = syntaxTokens.first?.kind else {
+        return file.rangesAndTokens(matching: pattern).filter { matchRange, syntaxTokens in
+            guard let syntaxToken = syntaxTokens.first, let syntaxKind = syntaxToken.kind else {
                 return false
             }
-            return syntaxTokens.isNotEmpty && SyntaxKind.commentKinds.contains(syntaxKind)
+            guard SyntaxKind.commentKinds.contains(syntaxKind) else {
+                return false
+            }
+            let tokenLocation = Location(file: file, byteOffset: ByteCount(syntaxToken.offset.value))
+            let matchLocation = Location(file: file, characterOffset: matchRange.location)
+            // Skip those MARKs that are part of a multiline comment
+            guard let tokenLine = tokenLocation.line, let matchLine = matchLocation.line, matchLine == tokenLine else {
+                return false
+            }
+            return true
         }.compactMap { range, syntaxTokens in
             let byteRange = ByteRange(location: syntaxTokens[0].offset, length: 0)
             let identifierRange = file.stringView.byteRangeToNSRange(byteRange)
@@ -212,6 +223,21 @@ private let issue1029Correction = Example("""
     extension MarkTest {}
     """)
 
+// https://github.com/realm/SwiftLint/issues/1749
+// https://github.com/realm/SwiftLint/issues/3841
+private let issue1749Example = Example("""
+    /*
+    func test1() {
+    }
+    //MARK: mark
+    func test2() {
+    }
+    */
+    """)
+
+// This example should not trigger changes
+private let issue1749Correction = issue1749Example
+
 // These need to be at the bottom of the file to work around https://bugs.swift.org/browse/SR-10486
 
 private let nonSpace = "[^ ]"