Fix trailingCommas logic for init declarations

Author: nicklockwood

Sources/ParsingHelpers.swift

@@ -3236,7 +3236,7 @@ extension Formatter {
         /// `foo()`, `@foo()`, or `#foo()`
         /// Exclude keywords to avoid confusing `return (...)`, `as? (...)`, `{ _ in (...) }`, etc.
         let isFunctionIdentifier = { (token: Token) in
-            token.isIdentifier || token.isAttribute || (token.isKeyword && token.string.hasPrefix("#"))
+            token.isIdentifier || token.isAttribute || (token.isKeyword && token.string.hasPrefix("#") || token.string == "init")
         }
 
         if isFunctionIdentifier(tokens[previousToken]) {

Tests/Rules/TrailingClosuresTests.swift

@@ -41,14 +41,14 @@ class TrailingClosuresTests: XCTestCase {
         testFormatting(for: input, rule: .trailingClosures)
     }
 
-    func testClosureArgumentInExpressionNotMadeTrailing() {
+    func testClosureArgumentInIfStatementNotMadeTrailing() {
         let input = """
         if let foo = foo(foo: 5, { /* some code */ }) {}
         """
         testFormatting(for: input, rule: .trailingClosures)
     }
 
-    func testClosureArgumentInCompoundExpressionNotMadeTrailing() {
+    func testClosureArgumentInCompoundIfStatementNotMadeTrailing() {
         let input = """
         if let foo = foo(foo: 5, { /* some code */ }), let bar = bar(bar: 2, { /* some code */ }) {}
         """
@@ -75,6 +75,23 @@ class TrailingClosuresTests: XCTestCase {
         testFormatting(for: input, output, rule: .trailingClosures)
     }
 
+    func testAnonymousInitClosureArgumentMadeTrailing() {
+        let input = """
+        Foo.init({ foo = bar })
+        """
+        let output = """
+        Foo.init { foo = bar }
+        """
+        testFormatting(for: input, output, rule: .trailingClosures, exclude: [.redundantInit])
+    }
+
+    func testNamedInitClosureArgumentNotMadeTrailing() {
+        let input = """
+        Foo.init(bar: { foo = bar })
+        """
+        testFormatting(for: input, rule: .trailingClosures, exclude: [.redundantInit])
+    }
+
     func testNoRemoveParensAroundClosureFollowedByOpeningBrace() {
         let input = """
         foo({ bar }) { baz }

Tests/Rules/TrailingCommasTests.swift

@@ -1798,6 +1798,46 @@ class TrailingCommasTests: XCTestCase {
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
+    func testMultiElementListsRemovesCommaFromSingleElementInit() {
+        let input = """
+        public init(
+            a: Int,
+        ) {
+            print(a)
+        }
+        """
+        let output = """
+        public init(
+            a: Int
+        ) {
+            print(a)
+        }
+        """
+        let options = FormatOptions(trailingCommas: .multiElementLists, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testMultiElementListsAddCommaToInit() {
+        let input = """
+        public init(
+            a: Int,
+            b: Int
+        ) {
+            print(a, b)
+        }
+        """
+        let output = """
+        public init(
+            a: Int,
+            b: Int,
+        ) {
+            print(a, b)
+        }
+        """
+        let options = FormatOptions(trailingCommas: .multiElementLists, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
     func testTrailingCommasNotRemovedFromInitParametersWithAlwaysOption() {
         let input = """
         public init(
@@ -1810,6 +1850,25 @@ class TrailingCommasTests: XCTestCase {
         testFormatting(for: input, rule: .trailingCommas, options: options, exclude: [.unusedArguments])
     }
 
+    func testTrailingCommasAddedToInitParametersWithAlwaysOption() {
+        let input = """
+        public init(
+            parameter: Parameter
+        ) {
+            // test
+        }
+        """
+        let output = """
+        public init(
+            parameter: Parameter,
+        ) {
+            // test
+        }
+        """
+        let options = FormatOptions(trailingCommas: .always, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options, exclude: [.unusedArguments])
+    }
+
     func testTrailingCommaNotRemovedFromTupleTypeSwift6_1() {
         let input = """
         let foo: (