diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index 4b6971bb..6f244b2a 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -19,7 +19,7 @@ jobs:
       linux_5_10_arguments_override: "--explicit-target-dependency-import-check error"
       linux_6_0_arguments_override: "--explicit-target-dependency-import-check error"
       linux_nightly_6_0_arguments_override: "--explicit-target-dependency-import-check error"
-      linux_nightly_main_enabled: false
+      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error"
 
   integration-test:
     name: Integration test
diff --git a/Sources/OpenAPIRuntime/Base/Acceptable.swift b/Sources/OpenAPIRuntime/Base/Acceptable.swift
index fb19799f..2f1b5e21 100644
--- a/Sources/OpenAPIRuntime/Base/Acceptable.swift
+++ b/Sources/OpenAPIRuntime/Base/Acceptable.swift
@@ -11,6 +11,7 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
+import Foundation
 
 /// The protocol that all generated `AcceptableContentType` enums conform to.
 public protocol AcceptableProtocol: RawRepresentable, Sendable, Hashable, CaseIterable where RawValue == String {}
diff --git a/Sources/OpenAPIRuntime/Base/ContentDisposition.swift b/Sources/OpenAPIRuntime/Base/ContentDisposition.swift
index c0b25074..11a43dc0 100644
--- a/Sources/OpenAPIRuntime/Base/ContentDisposition.swift
+++ b/Sources/OpenAPIRuntime/Base/ContentDisposition.swift
@@ -11,6 +11,7 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
+import Foundation
 
 /// A parsed representation of the `content-disposition` header described by RFC 6266 containing only
 /// the features relevant to OpenAPI multipart bodies.
diff --git a/Sources/OpenAPIRuntime/Interface/CurrencyTypes.swift b/Sources/OpenAPIRuntime/Interface/CurrencyTypes.swift
index 7093bd75..9e3e4542 100644
--- a/Sources/OpenAPIRuntime/Interface/CurrencyTypes.swift
+++ b/Sources/OpenAPIRuntime/Interface/CurrencyTypes.swift
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 import HTTPTypes
+import Foundation
 
 /// A container for request metadata already parsed and validated
 /// by the server transport.
diff --git a/Sources/OpenAPIRuntime/Multipart/MultipartBoundaryGenerator.swift b/Sources/OpenAPIRuntime/Multipart/MultipartBoundaryGenerator.swift
index 39bc9d21..c3397ba2 100644
--- a/Sources/OpenAPIRuntime/Multipart/MultipartBoundaryGenerator.swift
+++ b/Sources/OpenAPIRuntime/Multipart/MultipartBoundaryGenerator.swift
@@ -11,6 +11,7 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
+import Foundation
 
 /// A generator of a new boundary string used by multipart messages to separate parts.
 public protocol MultipartBoundaryGenerator: Sendable {
diff --git a/Tests/OpenAPIRuntimeTests/Base/Test_OpenAPIValue.swift b/Tests/OpenAPIRuntimeTests/Base/Test_OpenAPIValue.swift
index 7049502e..277044b0 100644
--- a/Tests/OpenAPIRuntimeTests/Base/Test_OpenAPIValue.swift
+++ b/Tests/OpenAPIRuntimeTests/Base/Test_OpenAPIValue.swift
@@ -12,8 +12,8 @@
 //
 //===----------------------------------------------------------------------===//
 import XCTest
-#if canImport(Foundation)
-@preconcurrency import Foundation
+import Foundation
+#if canImport(CoreFoundation)
 import CoreFoundation
 #endif
 @_spi(Generated) @testable import OpenAPIRuntime
diff --git a/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartBytesToFramesSequence.swift b/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartBytesToFramesSequence.swift
index acdee3f4..36eb2301 100644
--- a/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartBytesToFramesSequence.swift
+++ b/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartBytesToFramesSequence.swift
@@ -14,6 +14,7 @@
 import XCTest
 @_spi(Generated) @testable import OpenAPIRuntime
 import Foundation
+import HTTPTypes
 
 final class Test_MultipartBytesToFramesSequence: Test_Runtime {
     func test() async throws {
diff --git a/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartFramesToBytesSequence.swift b/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartFramesToBytesSequence.swift
index de487ed6..da87af47 100644
--- a/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartFramesToBytesSequence.swift
+++ b/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartFramesToBytesSequence.swift
@@ -14,6 +14,7 @@
 import XCTest
 @_spi(Generated) @testable import OpenAPIRuntime
 import Foundation
+import HTTPTypes
 
 final class Test_MultipartFramesToBytesSequence: Test_Runtime {
     func test() async throws {
diff --git a/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartFramesToRawPartsSequence.swift b/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartFramesToRawPartsSequence.swift
index 4a75b727..143993a7 100644
--- a/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartFramesToRawPartsSequence.swift
+++ b/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartFramesToRawPartsSequence.swift
@@ -14,6 +14,7 @@
 import XCTest
 @_spi(Generated) @testable import OpenAPIRuntime
 import Foundation
+import HTTPTypes
 
 final class Test_MultipartFramesToRawPartsSequence: Test_Runtime {
     func test() async throws {
diff --git a/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartRawPartsToFramesSequence.swift b/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartRawPartsToFramesSequence.swift
index 5017e532..826ef34f 100644
--- a/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartRawPartsToFramesSequence.swift
+++ b/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartRawPartsToFramesSequence.swift
@@ -14,6 +14,7 @@
 import XCTest
 @_spi(Generated) @testable import OpenAPIRuntime
 import Foundation
+import HTTPTypes
 
 final class Test_MultipartRawPartsToFramesSequence: Test_Runtime {
     func test() async throws {
diff --git a/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartValidationSequence.swift b/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartValidationSequence.swift
index 3951e864..0343966a 100644
--- a/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartValidationSequence.swift
+++ b/Tests/OpenAPIRuntimeTests/Multipart/Test_MultipartValidationSequence.swift
@@ -14,6 +14,7 @@
 import XCTest
 @_spi(Generated) @testable import OpenAPIRuntime
 import Foundation
+import HTTPTypes
 
 final class Test_MultipartValidationSequence: Test_Runtime {
     func test() async throws {