Ignore unused_closure_parameter on inline closures

Fixes realm#1161

CHANGELOG.md

@@ -44,6 +44,10 @@
 * Fix `redundant_void_return` matches if return type starts with Void~.  
   [Hayashi Tatsuya](https://github.com/sora0077)
 
+* Ignore `unused_closure_parameter` rule on closures that are called inline.  
+  [Marcelo Fabri](https://github.com/marcelofabri)
+  [#1161](https://github.com/realm/SwiftLint/issues/1161)
+
 ## 0.16.1: Commutative Fabric Sheets
 
 ##### Breaking

Source/SwiftLintFramework/Rules/UnusedClosureParameterRule.swift

@@ -33,7 +33,11 @@ public struct UnusedClosureParameterRule: ASTRule, ConfigurationProviderRule, Co
             "}",
             "genericsFunc { (a: Type, b) in\n" +
                 "a + b\n" +
-            "}\n"
+            "}\n",
+            "var label: UILabel = { (lbl: UILabel) -> UILabel in\n" +
+            "   lbl.backgroundColor = .red\n" +
+            "   return lbl\n" +
+            "}(UILabel())\n"
         ],
         triggeringExamples: [
             "[1, 2].map { ↓number in\n return 3\n}\n",
@@ -81,6 +85,7 @@ public struct UnusedClosureParameterRule: ASTRule, ConfigurationProviderRule, Co
     private func violationRanges(in file: File, dictionary: [String: SourceKitRepresentable],
                                  kind: SwiftExpressionKind) -> [(range: NSRange, name: String)] {
         guard kind == .call,
+            !isClosure(dictionary: dictionary),
             let offset = dictionary.offset,
             let length = dictionary.length,
             let nameOffset = dictionary.nameOffset,
@@ -133,6 +138,14 @@ public struct UnusedClosureParameterRule: ASTRule, ConfigurationProviderRule, Co
         }
     }
 
+    private func isClosure(dictionary: [String: SourceKitRepresentable]) -> Bool {
+        return dictionary.name.flatMap { name -> Bool in
+            let length = name.bridge().length
+            let range = NSRange(location: 0, length: length)
+            return regex("\\A\\s*\\{").firstMatch(in: name, options: [], range: range) != nil
+        } ?? false
+    }
+
     private func violationRanges(in file: File,
                                  dictionary: [String: SourceKitRepresentable]) -> [NSRange] {
         return dictionary.substructure.flatMap { subDict -> [NSRange] in