Find the correct case colon.

Rules.md

@@ -9995,6 +9995,51 @@ UIView.animate(withDuration: 1.0) {
 }
 ```
 
+```swift
+switch myvar {
+case MyFunc(x: [1, 2, YourFunc(a: 23)], y: 2):
+    var three = 3
+    fallthrough
+default:
+    var three = 4
+}
+```
+
+```swift
+switch myvar {
+case .alpha:
+    var one = 1
+case .beta:
+    var three = 3
+    fallthrough
+default:
+    var four = 4
+}
+```
+
+```swift
+let aPoint = (1, -1)
+switch aPoint {
+case let (x, y) where x == y:
+    let A = "A"
+case let (x, y) where x == -y:
+    let B = "B"
+    fallthrough
+default:
+    let C = "C"
+}
+```
+
+```swift
+switch myvar {
+case MyFun(with: { $1 }):
+    let one = 1
+    fallthrough
+case "abc":
+    let two = 2
+}
+```
+
 </details>
 <details>
 <summary>Triggering Examples</summary>
@@ -10011,6 +10056,49 @@ UIView.animate(withDuration: 1.0, animations: {
 }
 ```
 
+```swift
+switch myvar {
+case MyFunc(x: [1, 2, YourFunc(a: 23)], y: 2):
+    ↓fallthrough
+default:
+    var three = 4
+}
+```
+
+```swift
+switch myvar {
+case .alpha:
+    var one = 1
+case .beta:
+    ↓fallthrough
+case .gamma:
+    var three = 3
+default:
+  var four = 4
+}
+```
+
+```swift
+let aPoint = (1, -1)
+switch aPoint {
+case let (x, y) where x == y:
+    let A = "A"
+case let (x, y) where x == -y:
+    ↓fallthrough
+default:
+    let B = "B"
+}
+```
+
+```swift
+switch myvar {
+case MyFun(with: { $1 }):
+    ↓fallthrough
+case "abc":
+    let two = 2
+}
+```
+
 </details>
 
 

Source/SwiftLintFramework/Rules/NoFallthroughOnlyRule.swift

@@ -39,6 +39,47 @@ public struct NoFallthroughOnlyRule: ASTRule, ConfigurationProviderRule {
                // comment
                var two = 2
             }
+            """,
+            """
+            switch myvar {
+            case MyFunc(x: [1, 2, YourFunc(a: 23)], y: 2):
+                var three = 3
+                fallthrough
+            default:
+                var three = 4
+            }
+            """,
+            """
+            switch myvar {
+            case .alpha:
+                var one = 1
+            case .beta:
+                var three = 3
+                fallthrough
+            default:
+                var four = 4
+            }
+            """,
+            """
+            let aPoint = (1, -1)
+            switch aPoint {
+            case let (x, y) where x == y:
+                let A = "A"
+            case let (x, y) where x == -y:
+                let B = "B"
+                fallthrough
+            default:
+                let C = "C"
+            }
+            """,
+            """
+            switch myvar {
+            case MyFun(with: { $1 }):
+                let one = 1
+                fallthrough
+            case "abc":
+                let two = 2
+            }
             """
         ],
         triggeringExamples: [
@@ -75,6 +116,45 @@ public struct NoFallthroughOnlyRule: ASTRule, ConfigurationProviderRule {
             case 2:
                 var a = 2
             }
+            """,
+            """
+            switch myvar {
+            case MyFunc(x: [1, 2, YourFunc(a: 23)], y: 2):
+                ↓fallthrough
+            default:
+                var three = 4
+            }
+            """,
+            """
+            switch myvar {
+            case .alpha:
+                var one = 1
+            case .beta:
+                ↓fallthrough
+            case .gamma:
+                var three = 3
+            default:
+              var four = 4
+            }
+            """,
+            """
+            let aPoint = (1, -1)
+            switch aPoint {
+            case let (x, y) where x == y:
+                let A = "A"
+            case let (x, y) where x == -y:
+                ↓fallthrough
+            default:
+                let B = "B"
+            }
+            """,
+            """
+            switch myvar {
+            case MyFun(with: { $1 }):
+                ↓fallthrough
+            case "abc":
+                let two = 2
+            }
             """
         ]
     )
@@ -88,7 +168,7 @@ public struct NoFallthroughOnlyRule: ASTRule, ConfigurationProviderRule {
             let offset = dictionary.offset,
             case let nsstring = file.contents.bridge(),
             let range = nsstring.byteRangeToNSRange(start: offset, length: length),
-            let colonLocation = file.match(pattern: ":", range: range).first?.0.location
+            let colonLocation = findCaseColon(text: nsstring, range: range)
         else {
             return []
         }
@@ -112,4 +192,37 @@ public struct NoFallthroughOnlyRule: ASTRule, ConfigurationProviderRule {
 
         return []
     }
+
+    // Find the first colon that exists outside of all enclosing delimiters
+    private func findCaseColon(text: NSString, range: NSRange) -> Int? {
+        var nParen = 0
+        var nBrace = 0
+        var nBrack = 0
+        for index in range.location..<(range.location + range.length) {
+            let char = text.substring(with: NSRange(location: index, length: 1))
+            if char == "(" {
+                nParen += 1
+            }
+            if char == ")" {
+                nParen -= 1
+            }
+            if char == "[" {
+                nBrack += 1
+            }
+            if char == "]" {
+                nBrack -= 1
+            }
+            if char == "{" {
+                nBrace += 1
+            }
+            if char == "}" {
+                nBrace -= 1
+            }
+
+            if nParen == 0 && nBrack == 0 && nBrace == 0 && char == ":" {
+                return index
+            }
+        }
+        return nil
+    }
 }