A return followed by default has no expression associated with it.

Author: DougGregor

Sources/SwiftParser/Statements.swift

@@ -865,7 +865,7 @@ extension Parser {
     let expr: RawExprSyntax?
     if
       !self.at(any: [
-        .rightBrace, .caseKeyword, .semicolon, .eof,
+        .rightBrace, .caseKeyword, .defaultKeyword, .semicolon, .eof,
         .poundIfKeyword, .poundErrorKeyword, .poundWarningKeyword,
         .poundEndifKeyword, .poundElseKeyword, .poundElseifKeyword
       ])

Tests/SwiftParserTest/Statements.swift

@@ -110,6 +110,21 @@ final class StatementTests: XCTestCase {
     )
 
     AssertParse("return true ? nil : nil")
+
+    AssertParse(
+      """
+      switch command {
+      case .start:
+        break
+
+      case .stop:
+        return
+
+      default:
+        break
+      }
+      """
+    )
   }
 
   func testSwitch() {