diff --git a/.swift-format b/.swift-format
index 41a022f26..176687e28 100644
--- a/.swift-format
+++ b/.swift-format
@@ -13,6 +13,8 @@
         "NoBlockComments": false,
         "OrderedImports": true,
         "UseLetInEveryBoundCaseVariable": false,
-        "UseSynthesizedInitializer": false
+        "UseSynthesizedInitializer": false,
+        "ReturnVoidInsteadOfEmptyTuple": true,
+        "NoVoidReturnOnFunctionSignature": true,
     }
 }
diff --git a/Sources/swift-format/Frontend/FormatFrontend.swift b/Sources/swift-format/Frontend/FormatFrontend.swift
index a205b6405..0e8fca9d2 100644
--- a/Sources/swift-format/Frontend/FormatFrontend.swift
+++ b/Sources/swift-format/Frontend/FormatFrontend.swift
@@ -40,7 +40,7 @@ class FormatFrontend: Frontend {
       return
     }
 
-    let diagnosticHandler: (SwiftDiagnostics.Diagnostic, SourceLocation) -> () = {
+    let diagnosticHandler: (SwiftDiagnostics.Diagnostic, SourceLocation) -> Void = {
       (diagnostic, location) in
       guard !self.lintFormatOptions.ignoreUnparsableFiles else {
         // No diagnostics should be emitted in this mode.