Add support for Foundation TimeInterval

Sources/SwiftExtract/SwiftTypes/SwiftKnownModules.swift

@@ -129,6 +129,8 @@ private let foundationEssentialsSourceFile: SourceFileSyntax = """
     public init(timeIntervalSince1970: Double)
   }
 
+  public typealias TimeInterval = Double
+
   public struct UUID {}
 
   public struct URL {

Tests/JExtractSwiftTests/TimeIntervalTests.swift

@@ -0,0 +1,126 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2026 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
+//
+//===----------------------------------------------------------------------===//
+
+import JExtractSwiftLib
+import SwiftJavaConfigurationShared
+import Testing
+
+struct TimeIntervalTests {
+  @Test(
+    "Import: accept TimeInterval (resolves to Double)",
+    arguments: [
+      (
+        JExtractGenerationMode.jni,
+        /* expected Java chunks */
+        [
+          """
+          public static void delay(double seconds) {
+            SwiftModule.$delay(seconds);
+          }
+          """
+        ],
+        /* expected Swift chunks */
+        [
+          """
+          @_cdecl("Java_com_example_swift_SwiftModule__00024delay__D")
+          public func Java_com_example_swift_SwiftModule__00024delay__D(environment: UnsafeMutablePointer<JNIEnv?>!, thisClass: jclass, seconds: jdouble) {
+            SwiftModule.delay(seconds: Double(fromJNI: seconds, in: environment))
+          }
+          """
+        ],
+      )
+    ]
+  )
+  func func_accept_timeInterval(
+    mode: JExtractGenerationMode,
+    expectedJavaChunks: [String],
+    expectedSwiftChunks: [String]
+  ) throws {
+    let text =
+      """
+      import Foundation
+
+      public func delay(seconds: TimeInterval)
+      """
+
+    try assertOutput(
+      input: text,
+      mode,
+      .java,
+      detectChunkByInitialLines: 1,
+      expectedChunks: expectedJavaChunks
+    )
+
+    try assertOutput(
+      input: text,
+      mode,
+      .swift,
+      detectChunkByInitialLines: 1,
+      expectedChunks: expectedSwiftChunks
+    )
+  }
+
+  @Test(
+    "Import: return TimeInterval (resolves to Double)",
+    arguments: [
+      (
+        JExtractGenerationMode.jni,
+        /* expected Java chunks */
+        [
+          """
+          public static double now() {
+            return SwiftModule.$now();
+          }
+          """
+        ],
+        /* expected Swift chunks */
+        [
+          """
+          @_cdecl("Java_com_example_swift_SwiftModule__00024now__")
+          public func Java_com_example_swift_SwiftModule__00024now__(environment: UnsafeMutablePointer<JNIEnv?>!, thisClass: jclass) -> jdouble {
+            return SwiftModule.now()
+          }
+          """
+        ]
+      )
+    ]
+  )
+  func func_return_timeInterval(
+    mode: JExtractGenerationMode,
+    expectedJavaChunks: [String],
+    expectedSwiftChunks: [String]
+  ) throws {
+    let text =
+      """
+      import Foundation
+      public func now() -> TimeInterval
+      """
+
+    try assertOutput(
+      input: text,
+      mode,
+      .java,
+      detectChunkByInitialLines: 1,
+      expectedChunks: expectedJavaChunks
+    )
+
+    try assertOutput(
+      input: text,
+      mode,
+      .swift,
+      detectChunkByInitialLines: 1,
+      expectedChunks: expectedSwiftChunks
+    )
+  }
+}