JNI: avoid enum case record names that collide with enclosing types

Samples/SwiftJavaExtractJNISampleApp/Sources/MySwiftLibrary/EnumCaseCollision.swift

@@ -0,0 +1,19 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+public enum EnumCaseCollision {
+  case enumCaseCollision(Int64)
+  case `case`(Int64)
+  case plain(Int64)
+}

Samples/SwiftJavaExtractJNISampleApp/src/test/java/com/example/swift/EnumCaseCollisionTest.java

@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+package com.example.swift;
+
+import org.junit.jupiter.api.Test;
+import org.swift.swiftkit.core.SwiftArena;
+import static org.junit.jupiter.api.Assertions.*;
+
+public class EnumCaseCollisionTest {
+    @Test
+    void renamedRecordsPreserveTheirPayloads() {
+        try (var arena = SwiftArena.ofConfined()) {
+            var value = EnumCaseCollision.enumCaseCollision(42, arena);
+            var payload = assertInstanceOf(EnumCaseCollision.Case.EnumCaseCollisionCase.class, value.getCase());
+            assertEquals(42, payload.arg0());
+            var keyword = EnumCaseCollision.case_(7, arena);
+            assertEquals(7, assertInstanceOf(EnumCaseCollision.Case.CaseCase.class, keyword.getCase()).arg0());
+            var plain = EnumCaseCollision.plain(9, arena);
+            assertEquals(9, assertInstanceOf(EnumCaseCollision.Case.Plain.class, plain.getCase()).arg0());
+        }
+    }
+}

Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+JavaTranslation.swift

@@ -151,7 +151,13 @@ extension JNISwift2JavaGenerator {
       let associatedValueTypes = enumCase.parameters.map { param in
         param.type.description
       }.joined(separator: .comma)
-      let javaCaseClassName = enumCase.name.firstCharacterUppercased
+      var javaCaseClassName = enumCase.name.firstCharacterUppercased
+      // Java forbids a nested record from sharing an enclosing type's name.
+      // For example Calendar.Component.Case.Calendar must be CalendarCase.
+      let enclosingNames = enumCase.enumType.nominalTypeDecl.qualifiedTypeName.components + ["Case"]
+      while enclosingNames.contains(javaCaseClassName) {
+        javaCaseClassName += "Case"
+      }
       let resultType = knownTypes.optionalSugar(
         .tuple(
           enumCase.parameters.map {

Tests/JExtractSwiftTests/JNI/JNIEnumTests.swift

@@ -30,6 +30,29 @@ struct JNIEnumTests {
     }
     """
 
+  @Test(
+    "Enum case records avoid enclosing Java type names",
+    arguments: [("message", "MessageCase"), ("caseCase", "CaseCaseCase"), ("`case`", "CaseCaseCase"), ("plain", "Plain")]
+  )
+  func enclosingNameCollisions_java(caseName: String, recordName: String) throws {
+    try assertOutput(
+      input: """
+        public struct CaseCase {
+          public enum Message {
+            case \(caseName)(Int64)
+          }
+        }
+        """,
+      .jni,
+      .java,
+      expectedChunks: [
+        "record \(recordName)(long arg0) implements Case {}",
+        "public java.util.Optional<Case.\(recordName)> getAs\(recordName)()",
+      ],
+      notExpectedChunks: ["record Message(", "record Case(", "record CaseCase("]
+    )
+  }
+
   @Test
   func generatesJavaClass() throws {
     try assertOutput(