Update trailingCommas rule to support more case from SE-0439, including if statements, guard statements, subscripts, capture lists, generic arguments

Rules.md

@@ -3087,47 +3087,40 @@ Option | Description
     foo,
     bar,
 -   baz
-  ]
-
-  let array = [
-    foo,
-    bar,
 +   baz,
   ]
 ```
 
 ```diff
-func foo(
--   bar _: Int
-) {}
-
-func foo(
-+   bar _: Int,
-) {}
+  func foo(
+      bar _: Int,
+-     baaz _: Int
++     baaz _: Int
+  ) {}
 ```
 
 ```diff
-let foo = (
-    bar: 0,
--   baz: 1
-)
-
-let foo = (
-    bar: 0,
-+   baz: 1,
-)
+  let foo = (
+      bar: 0,
+-     baz: 1
++     baz: 1,
+  )
 ```
 
 ```diff
-@Foo(
-    "bar",
--   "baz"
-)
+  if
+      let foo,
+-     let baaz
++     let baaz,
+  { ... }
+```
 
-@Foo(
-    "bar",
-+   "baz",
-)
+```diff
+  guard
+      let foo,
+-     let baaz
++     let baaz,
+  else { return }
 ```
 
 </details>

Sources/FormattingHelpers.swift

@@ -1374,7 +1374,7 @@ extension Formatter {
 
         while let conditionalBranchIndex = nextConditionalBranchIndex,
               conditionalBranchIndex == ifIndex || tokens[conditionalBranchIndex] == .keyword("else"),
-              let startOfBody = index(of: .startOfScope("{"), after: conditionalBranchIndex),
+              let startOfBody = startOfConditionalBranchBody(after: conditionalBranchIndex),
               let endOfBody = endOfScope(at: startOfBody)
         {
             branches.append((startOfBranch: startOfBody, endOfBranch: endOfBody))
@@ -1390,6 +1390,20 @@ extension Formatter {
         return branches
     }
 
+    /// Returns the `startOfScope("{")` token index for this conditional branch
+    func startOfConditionalBranchBody(after index: Int) -> Int? {
+        guard let startOfBody = self.index(of: .startOfScope("{"), after: index) else { return nil }
+
+        // If we find a closure, skip over it.
+        if isStartOfClosure(at: startOfBody),
+           let endOfClosure = endOfScope(at: startOfBody)
+        {
+            return startOfConditionalBranchBody(after: endOfClosure)
+        }
+
+        return startOfBody
+    }
+
     /// Finds all of the branch bodies in a switch statement.
     /// Returns the index of the `startOfScope` and `endOfScope` of each branch.
     func switchStatementBranches(at switchIndex: Int) -> [ConditionalBranch]? {

Sources/ParsingHelpers.swift

@@ -920,11 +920,30 @@ extension Formatter {
                 return true
             }
         case .delimiter(","):
-            guard let scope = scope ?? currentScope(at: i) else {
-                return false
+            // If this is the trailing comma in an if/guard/while condition list, then don't indent the following code (the condition body)
+            if isConditionalStatement(at: i),
+               let startOfBranchBody = startOfConditionalBranchBody(after: i),
+               let nextToken = index(of: .nonSpaceOrCommentOrLinebreak, after: i)
+            {
+                if nextToken == startOfBranchBody {
+                    return true
+                }
+
+                // Handle guard statement lists ending with `else {` instead of just `{`
+                if tokens[nextToken] == .keyword("else"),
+                   let followingToken = index(of: .nonSpaceOrCommentOrLinebreak, after: nextToken),
+                   followingToken == startOfBranchBody
+                {
+                    return true
+                }
             }
+
             // For arrays or argument lists, we already indent
-            return ["<", "[", "(", "case", "default"].contains(scope.string)
+            if let scope = scope ?? currentScope(at: i) {
+                return ["<", "[", "(", "case", "default"].contains(scope.string)
+            }
+
+            return false
         case .delimiter(":"):
             guard let scope = scope ?? currentScope(at: i) else {
                 return false

Sources/Rules/OpaqueGenericParameters.swift

@@ -225,6 +225,10 @@ public extension FormatRule {
                 [type.definitionSourceRange] + type.conformances.map(\.sourceRange)
             })
 
+            if genericsEligibleToRemove.isEmpty {
+                return
+            }
+
             // We perform modifications to the function signature in reverse order
             // so we don't invalidate any of the indices we've recorded. So first
             // we remove components of the where clause.

Sources/Rules/TrailingCommas.swift

@@ -15,85 +15,54 @@ public extension FormatRule {
         help: "Add or remove trailing commas where applicable.",
         options: ["commas"]
     ) { formatter in
-        formatter.forEach(.endOfScope("]")) { i, _ in
-            guard let prevTokenIndex = formatter.index(of: .nonSpaceOrComment, before: i),
-                  let scopeType = formatter.scopeType(at: i)
-            else {
-                return
-            }
-            switch scopeType {
-            case .array, .dictionary:
-                switch formatter.tokens[prevTokenIndex] {
-                case .linebreak:
-                    guard let prevTokenIndex = formatter.index(
-                        of: .nonSpaceOrCommentOrLinebreak, before: prevTokenIndex + 1
-                    ) else {
-                        break
-                    }
-                    switch formatter.tokens[prevTokenIndex] {
-                    case .startOfScope("["), .delimiter(":"):
-                        break // do nothing
-                    case .delimiter(","):
-                        if !formatter.options.trailingCommas {
-                            formatter.removeToken(at: prevTokenIndex)
-                        }
-                    default:
-                        if formatter.options.trailingCommas {
-                            formatter.insert(.delimiter(","), at: prevTokenIndex + 1)
-                        }
-                    }
-                case .delimiter(","):
-                    formatter.removeToken(at: prevTokenIndex)
+        formatter.forEachToken { i, token in
+            switch token {
+            case .endOfScope("]"):
+                switch formatter.scopeType(at: i) {
+                case .array, .dictionary:
+                    formatter.addOrRemoveTrailingComma(before: i, trailingCommaSupported: true)
+                case .subscript, .captureList:
+                    formatter.addOrRemoveTrailingComma(before: i, trailingCommaSupported: formatter.options.swiftVersion >= "6.1")
                 default:
-                    break
+                    return
                 }
-            default:
-                return
-            }
-        }
 
-        guard formatter.options.swiftVersion >= "6.1" else { return }
+            case .endOfScope(")"), .endOfScope(">"):
+                formatter.addOrRemoveTrailingComma(before: i, trailingCommaSupported: formatter.options.swiftVersion >= "6.1")
 
-        formatter.forEach(.endOfScope(")")) { i, _ in
-            guard let startIndex = formatter.startOfScope(at: i),
-                  formatter.tokens[startIndex] == .startOfScope("(")
-            else {
-                return
-            }
+            case .keyword("if"):
+                guard let startOfConditions = formatter.index(of: .nonSpaceOrCommentOrLinebreak, after: i),
+                      let startOfBody = formatter.startOfConditionalBranchBody(after: startOfConditions)
+                else { return }
 
-            guard let prevToStartTokenIndex = formatter.index(of: .nonSpaceOrComment, before: startIndex) else {
-                return
-            }
+                formatter.addOrRemoveTrailingComma(before: startOfBody, trailingCommaSupported: formatter.options.swiftVersion >= "6.1")
 
-            guard formatter.tokens[prevToStartTokenIndex] != .delimiter(":") else {
-                return
-            }
+            case .keyword("guard"):
+                guard let startOfConditions = formatter.index(of: .nonSpaceOrCommentOrLinebreak, after: i),
+                      let startOfBody = formatter.startOfConditionalBranchBody(after: startOfConditions),
+                      let elseKeyword = formatter.index(of: .nonSpaceOrCommentOrLinebreak, before: startOfBody),
+                      formatter.tokens[elseKeyword] == .keyword("else")
+                else { return }
 
-            guard let prevToEndTokenIndex = formatter.index(of: .nonSpaceOrComment, before: i) else {
-                return
-            }
+                formatter.addOrRemoveTrailingComma(before: elseKeyword, trailingCommaSupported: formatter.options.swiftVersion >= "6.1")
 
-            switch formatter.tokens[prevToEndTokenIndex] {
-            case .linebreak:
-                guard let lastArgIndex = formatter.index(
-                    of: .nonSpaceOrCommentOrLinebreak, before: prevToEndTokenIndex + 1
-                ) else {
-                    break
+            case .keyword("while"):
+                guard let startOfConditions = formatter.index(of: .nonSpaceOrCommentOrLinebreak, after: i),
+                      let startOfBody = formatter.startOfConditionalBranchBody(after: startOfConditions)
+                else { return }
+
+                // Ensure this isn't a `repeat { ... } while ...` condition where any `{` token after the while keyword would be unrelated
+                if let previousToken = formatter.index(of: .nonSpaceOrCommentOrLinebreak, before: i),
+                   formatter.tokens[previousToken] == .endOfScope("}"),
+                   let startOfScope = formatter.startOfScope(at: previousToken),
+                   let tokenBeforeStartOfScope = formatter.index(of: .nonSpaceOrCommentOrLinebreak, before: startOfScope),
+                   formatter.tokens[tokenBeforeStartOfScope] == .keyword("repeat")
+                {
+                    return
                 }
-                switch formatter.tokens[lastArgIndex] {
-                case .delimiter(","):
-                    if !formatter.options.trailingCommas {
-                        formatter.removeToken(at: lastArgIndex)
-                    }
-                case .startOfScope("("):
-                    break
-                default:
-                    if formatter.options.trailingCommas {
-                        formatter.insert(.delimiter(","), at: lastArgIndex + 1)
-                    }
-                }
-            case .delimiter(","):
-                formatter.removeToken(at: prevToEndTokenIndex)
+
+                formatter.addOrRemoveTrailingComma(before: startOfBody, trailingCommaSupported: formatter.options.swiftVersion >= "6.1")
+
             default:
                 break
             }
@@ -105,48 +74,75 @@ public extension FormatRule {
             foo,
             bar,
         -   baz
-          ]
-
-          let array = [
-            foo,
-            bar,
         +   baz,
           ]
         ```
 
         ```diff
-        func foo(
-        -   bar _: Int
-        ) {}
-
-        func foo(
-        +   bar _: Int,
-        ) {}
+          func foo(
+              bar _: Int,
+        -     baaz _: Int
+        +     baaz _: Int
+          ) {}
         ```
 
         ```diff
-        let foo = (
-            bar: 0,
-        -   baz: 1
-        )
-
-        let foo = (
-            bar: 0,
-        +   baz: 1,
-        )
+          let foo = (
+              bar: 0,
+        -     baz: 1
+        +     baz: 1,
+          )
         ```
 
         ```diff
-        @Foo(
-            "bar",
-        -   "baz"
-        )
+          if
+              let foo,
+        -     let baaz
+        +     let baaz,
+          { ... }
+        ```
 
-        @Foo(
-            "bar",
-        +   "baz",
-        )
+        ```diff
+          guard
+              let foo,
+        -     let baaz
+        +     let baaz,
+          else { return }
         ```
         """
     }
 }
+
+extension Formatter {
+    /// Adds or removes a trailing comma before the given index that marks the end of a comma-separated list.
+    /// Trailing commas can always be removed. `trailingCommaSupported` indicates whether or not a trailing
+    /// comma is allowed at this position.
+    func addOrRemoveTrailingComma(before endOfListIndex: Int, trailingCommaSupported: Bool) {
+        guard let prevTokenIndex = index(of: .nonSpaceOrComment, before: endOfListIndex) else { return }
+
+        switch tokens[prevTokenIndex] {
+        case .linebreak:
+            guard let prevTokenIndex = index(
+                of: .nonSpaceOrCommentOrLinebreak, before: prevTokenIndex + 1
+            ) else {
+                break
+            }
+            switch tokens[prevTokenIndex] {
+            case .startOfScope("["), .delimiter(":"), .startOfScope("("):
+                break // do nothing
+            case .delimiter(","):
+                if !options.trailingCommas {
+                    removeToken(at: prevTokenIndex)
+                }
+            default:
+                if options.trailingCommas, trailingCommaSupported {
+                    insert(.delimiter(","), at: prevTokenIndex + 1)
+                }
+            }
+        case .delimiter(","):
+            removeToken(at: prevTokenIndex)
+        default:
+            break
+        }
+    }
+}

Tests/Rules/IndentTests.swift

@@ -4265,4 +4265,56 @@ class IndentTests: XCTestCase {
         """
         testFormatting(for: input, rule: .indent)
     }
+
+    func testNoIndentIfConditionBodyAfterTrailingCommaInClosure() {
+        let input = """
+        withTrailingClosure {
+            if
+                foo.bar,
+                foo.baaz(
+                    bar: foo.bar,
+                    baaz: foo.baaz,
+                ),
+            {
+                print("passed condition")
+            }
+        }
+        """
+
+        testFormatting(for: input, rule: .indent)
+    }
+
+    func testNoIndentGuardConditionBodyAfterTrailingComma() {
+        let input = """
+        guard
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz,
+            ),
+        else {
+            return
+        }
+        """
+
+        testFormatting(for: input, rule: .indent)
+    }
+
+    func testNoIndentGuardConditionBodyAfterTrailingCommaInClosure() {
+        let input = """
+        withTrailingClosure {
+            guard
+                foo.bar,
+                foo.baaz(
+                    bar: foo.bar,
+                    baaz: foo.baaz,
+                ),
+            else {
+                return
+            }
+        }
+        """
+
+        testFormatting(for: input, rule: .indent)
+    }
 }

Tests/Rules/RedundantReturnTests.swift

@@ -545,6 +545,30 @@ class RedundantReturnTests: XCTestCase {
                        options: options)
     }
 
+    func testRedundantIfStatementWithClosureCondition() {
+        let input = """
+        func foo(condition: Bool) -> String {
+            if condition, { true }(), { false }() {
+                return "foo"
+            } else {
+                return "bar"
+            }
+        }
+        """
+
+        let output = """
+        func foo(condition: Bool) -> String {
+            if condition, { true }(), { false }() {
+                "foo"
+            } else {
+                "bar"
+            }
+        }
+        """
+        let options = FormatOptions(swiftVersion: "5.9")
+        testFormatting(for: input, [output], rules: [.redundantReturn, .conditionalAssignment], options: options, exclude: [.redundantClosure])
+    }
+
     func testNonRedundantIfStatementReturnSwift5_9() {
         let input = """
         func foo(condition: Bool) -> String {

Tests/Rules/TrailingCommasTests.swift

@@ -288,6 +288,16 @@ class TrailingCommasTests: XCTestCase {
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
+    func testTrailingCommasNotAddedToFunctionParametersBeforeSwift6_1() {
+        let input = """
+        func foo(
+            bar _: Int
+        ) {}
+        """
+        let options = FormatOptions(trailingCommas: true)
+        testFormatting(for: input, rule: .trailingCommas, options: options)
+    }
+
     func testTrailingCommasRemovedFromFunctionParameters() {
         let input = """
         func foo(
@@ -299,7 +309,41 @@ class TrailingCommasTests: XCTestCase {
             bar _: Int
         ) {}
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasRemovedFromFunctionParametersWithParenOnSameLine_trailingCommasDisabled() {
+        let input = """
+        func foo(
+            bar _: Int,
+            baaz _: Int,)
+        {}
+        """
+        let output = """
+        func foo(
+            bar _: Int,
+            baaz _: Int)
+        {}
+        """
+        let options = FormatOptions(trailingCommas: false, closingParenPosition: .sameLine)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasRemovedFromFunctionParametersWithParenOnSameLine_trailingCommasEnabled() {
+        let input = """
+        func foo(
+            bar _: Int,
+            baaz _: Int,)
+        {}
+        """
+        let output = """
+        func foo(
+            bar _: Int,
+            baaz _: Int)
+        {}
+        """
+        let options = FormatOptions(trailingCommas: true, closingParenPosition: .sameLine)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -329,7 +373,7 @@ class TrailingCommasTests: XCTestCase {
             bar _: Int
         ) {}
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -367,7 +411,7 @@ class TrailingCommasTests: XCTestCase {
             )
         }
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -397,7 +441,7 @@ class TrailingCommasTests: XCTestCase {
             1
         )
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -431,7 +475,7 @@ class TrailingCommasTests: XCTestCase {
             baz: 1
         )
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -485,7 +529,7 @@ class TrailingCommasTests: XCTestCase {
             )
         }
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -539,7 +583,7 @@ class TrailingCommasTests: XCTestCase {
             )
         }
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -582,138 +626,314 @@ class TrailingCommasTests: XCTestCase {
 
     func testTrailingCommasAddedToIf() {
         let input = """
-        if (
-            true
-        ) {}
+        if
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz)
+        {
+            print("passed condition")
+        }
         """
         let output = """
-        if (
-            true,
-        ) {}
+        if
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz),
+        {
+            print("passed condition")
+        }
         """
-        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
-        testFormatting(for: input, output, rule: .trailingCommas,
-                       options: options, exclude: [.redundantParens])
+        let options = FormatOptions(trailingCommas: true, closingParenPosition: .sameLine, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasAddedToIfWithClosureCondition() {
+        let input = """
+        if
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz),
+            { true }()
+        {
+            print("passed condition")
+        }
+        """
+        let output = """
+        if
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz),
+            { true }(),
+        {
+            print("passed condition")
+        }
+        """
+        let options = FormatOptions(trailingCommas: true, closingParenPosition: .sameLine, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options, exclude: [.redundantClosure])
+    }
+
+    func testTrailingCommasNotAddedToIfBeforeSwift6_1() {
+        let input = """
+        if
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz)
+        {
+            print("passed condition")
+        }
+        """
+        let options = FormatOptions(trailingCommas: true, closingParenPosition: .sameLine)
+        testFormatting(for: input, rule: .trailingCommas, options: options, exclude: [.redundantParens])
     }
 
     func testTrailingCommasRemovedFromIf() {
         let input = """
-        if (
-            true,
-        ) {}
+        if
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz),
+        {
+            print("passed condition")
+        }
         """
         let output = """
-        if (
-            true
-        ) {}
+        if
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz)
+        {
+            print("passed condition")
+        }
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
-        testFormatting(for: input, output, rule: .trailingCommas,
-                       options: options, exclude: [.redundantParens])
+        let options = FormatOptions(trailingCommas: false, closingParenPosition: .sameLine)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasRemovedFromIfWithClosureArgument() {
+        let input = """
+        if
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz),
+            { true }(),
+        {
+            print("passed condition")
+        }
+        """
+        let output = """
+        if
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz),
+            { true }()
+        {
+            print("passed condition")
+        }
+        """
+        let options = FormatOptions(trailingCommas: false, closingParenPosition: .sameLine)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options, exclude: [.redundantClosure])
+    }
+
+    func testTrailingCommasRemovedFromSingleLineIf() {
+        let input = """
+        if foo.bar, foo.baaz(), {
+            print("passed condition")
+        }
+        """
+        let output = """
+        if foo.bar, foo.baaz() {
+            print("passed condition")
+        }
+        """
+        let options = FormatOptions(trailingCommas: true)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
     func testTrailingCommasAddedToGuard() {
         let input = """
-        guard (
-            true
-        ) else {
+        guard
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz)
+        else {
             return
         }
         """
         let output = """
-        guard (
-            true,
-        ) else {
+        guard
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz),
+        else {
             return
         }
         """
-        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
-        testFormatting(for: input, output, rule: .trailingCommas,
-                       options: options, exclude: [.redundantParens])
+        let options = FormatOptions(trailingCommas: true, closingParenPosition: .sameLine, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasNotAddedToGuardBeforeSwift6_1() {
+        let input = """
+        guard
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz)
+        else {
+            return
+        }
+        """
+        let options = FormatOptions(trailingCommas: true, closingParenPosition: .sameLine)
+        testFormatting(for: input, rule: .trailingCommas, options: options, exclude: [.redundantParens])
     }
 
     func testTrailingCommasRemovedFromGuard() {
         let input = """
-        guard (
-            true,
-        ) else {
+        guard
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz),
+        else {
             return
         }
         """
         let output = """
-        guard (
-            true
-        ) else {
+        guard
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz)
+        else {
             return
         }
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
-        testFormatting(for: input, output, rule: .trailingCommas,
-                       options: options, exclude: [.redundantParens])
+        let options = FormatOptions(trailingCommas: false, closingParenPosition: .sameLine)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasRemovedFromGuardWithClosureArgument() {
+        let input = """
+        guard
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz),
+            { true }(),
+        else {
+            return
+        }
+        """
+        let output = """
+        guard
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz),
+            { true }()
+        else {
+            return
+        }
+        """
+        let options = FormatOptions(trailingCommas: false, closingParenPosition: .sameLine)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options, exclude: [.redundantClosure])
+    }
+
+    func testTrailingCommasRemovedFromSingleLineGuard() {
+        let input = """
+        guard foo.bar, foo.baaz(), else {
+            return
+        }
+        """
+        let output = """
+        guard foo.bar, foo.baaz() else {
+            return
+        }
+        """
+        let options = FormatOptions(trailingCommas: true)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
     func testTrailingCommasAddedToWhile() {
         let input = """
-        while (
-            true
-        ) {}
+        while
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz
+            )
+        {
+            break
+        }
         """
         let output = """
-        while (
-            true,
-        ) {}
+        while
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz,
+            ),
+        {
+            break
+        }
         """
         let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
-        testFormatting(for: input, output, rule: .trailingCommas,
-                       options: options, exclude: [.redundantParens])
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasNotAddedToRepeatWhile() {
+        let input = """
+        repeat
+        {
+            print(foo)
+        } while foo
+
+        // Ensure we don't confuse this trailing closure for a condition in the while statement:
+        trailingClosure
+        {
+            print("foo")
+        }
+        """
+        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
+        testFormatting(for: input, rule: .trailingCommas, options: options, exclude: [.redundantParens, .braces, .indent])
     }
 
     func testTrailingCommasRemovedFromWhile() {
         let input = """
-        while (
-            true,
-        ) {}
+        while
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz,
+            ),
+        {
+            break
+        }
         """
         let output = """
-        while (
-            true
-        ) {}
+        while
+            foo.bar,
+            foo.baaz(
+                bar: foo.bar,
+                baaz: foo.baaz
+            )
+        {
+            break
+        }
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
-        testFormatting(for: input, output, rule: .trailingCommas,
-                       options: options, exclude: [.redundantParens])
-    }
-
-    func testTrailingCommasAddedToBool() {
-        let input = """
-        let foo: Bool = (
-            true && true
-        )
-        """
-        let output = """
-        let foo: Bool = (
-            true && true,
-        )
-        """
-        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
-        testFormatting(for: input, output, rule: .trailingCommas,
-                       options: options, exclude: [.redundantParens])
-    }
-
-    func testTrailingCommasRemovedFromBool() {
-        let input = """
-        let foo: Bool = (
-            true && true,
-        )
-        """
-        let output = """
-        let foo: Bool = (
-            true && true
-        )
-        """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
-        testFormatting(for: input, output, rule: .trailingCommas,
-                       options: options, exclude: [.redundantParens])
+        let options = FormatOptions(trailingCommas: false)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
     func testTrailingCommasNotAddedToTypeAnnotation() {
@@ -723,7 +943,7 @@ class TrailingCommasTests: XCTestCase {
             baz: Int
         )
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, rule: .trailingCommas, options: options)
     }
 
@@ -769,7 +989,7 @@ class TrailingCommasTests: XCTestCase {
         ): break
         }
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -803,7 +1023,7 @@ class TrailingCommasTests: XCTestCase {
             bar
         ) = (0, 1)
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -813,7 +1033,7 @@ class TrailingCommasTests: XCTestCase {
 
         )
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, rule: .trailingCommas,
                        options: options, exclude: [
                            .blankLinesAtEndOfScope,
@@ -859,7 +1079,7 @@ class TrailingCommasTests: XCTestCase {
         )
         \"""
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -897,7 +1117,7 @@ class TrailingCommasTests: XCTestCase {
         )
         struct Qux {}
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 
@@ -931,7 +1151,181 @@ class TrailingCommasTests: XCTestCase {
             "baz"
         )
         """
-        let options = FormatOptions(trailingCommas: false, swiftVersion: "6.1")
+        let options = FormatOptions(trailingCommas: false)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasAddedToGenericList() {
+        let input = """
+        struct S<
+            T1,
+            T2,
+            T3
+        > {}
+        """
+        let output = """
+        struct S<
+            T1,
+            T2,
+            T3,
+        > {}
+        """
+        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasRemovedFromGenericList() {
+        let input = """
+        struct S<
+            T1,
+            T2,
+            T3,
+        > {}
+        """
+        let output = """
+        struct S<
+            T1,
+            T2,
+            T3
+        > {}
+        """
+        let options = FormatOptions(trailingCommas: false)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasRemovedFromSingleLineGenericList() {
+        let input = """
+        struct S<T1, T2, T3,> {}
+        """
+        let output = """
+        struct S<T1, T2, T3> {}
+        """
+        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasAddedToCaptureList() {
+        let input = """
+        { [
+            capturedValue1,
+            capturedValue2
+        ] in
+        }
+        """
+        let output = """
+        { [
+            capturedValue1,
+            capturedValue2,
+        ] in
+        }
+        """
+        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasRemovedFromCaptureList() {
+        let input = """
+        { [
+            capturedValue1,
+            capturedValue2,
+        ] in
+        }
+        """
+        let output = """
+        { [
+            capturedValue1,
+            capturedValue2
+        ] in
+        }
+        """
+        let options = FormatOptions(trailingCommas: false)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasRemovedFromSingleLineCaptureList() {
+        let input = """
+        { [capturedValue1, capturedValue2,] in
+            print(capturedValue1, capturedValue2)
+        }
+        """
+        let output = """
+        { [capturedValue1, capturedValue2] in
+            print(capturedValue1, capturedValue2)
+        }
+        """
+        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasAddedToSubscript() {
+        let input = """
+        let value = m[
+            x,
+            y
+        ]
+        """
+        let output = """
+        let value = m[
+            x,
+            y,
+        ]
+        """
+        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasRemovedFromSubscript() {
+        let input = """
+        let value = m[
+            x,
+            y,
+        ]
+        """
+        let output = """
+        let value = m[
+            x,
+            y
+        ]
+        """
+        let options = FormatOptions(trailingCommas: false)
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testTrailingCommasRemovedFromSingleLineSubscript() {
+        let input = """
+        let value = m[x, y,]
+        """
+        let output = """
+        let value = m[x, y]
+        """
+        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
+        testFormatting(for: input, output, rule: .trailingCommas, options: options)
+    }
+
+    func testAddingTrailingCommaDoesntConflictWithOpaqueGenericParametersRule() {
+        let input = """
+        private func foo<
+            Foo: Bar,
+            Bar: Baaz
+        >(a: Foo, b: Foo)
+            where Foo == Bar
+        {
+            print(a, b)
+        }
+        """
+
+        let output = """
+        private func foo<
+            Foo: Bar,
+            Bar: Baaz,
+        >(a: Foo, b: Foo)
+            where Foo == Bar
+        {
+            print(a, b)
+        }
+        """
+
+        let options = FormatOptions(trailingCommas: true, swiftVersion: "6.1")
         testFormatting(for: input, output, rule: .trailingCommas, options: options)
     }
 }