diff --git a/Sources/Basics/Netrc.swift b/Sources/Basics/Netrc.swift
index 4bbd211cd78..fdfe4db25e0 100644
--- a/Sources/Basics/Netrc.swift
+++ b/Sources/Basics/Netrc.swift
@@ -13,7 +13,7 @@
 import Foundation
 
 /// Representation of Netrc configuration
-public struct Netrc {
+public struct Netrc: Sendable {
     /// Representation of `machine` connection settings & `default` connection settings.
     /// If `default` connection settings present, they will be last element.
     public let machines: [Machine]
@@ -37,7 +37,7 @@ public struct Netrc {
     }
 
     /// Representation of connection settings
-    public struct Machine: Equatable {
+    public struct Machine: Equatable, Sendable {
         public let name: String
         public let login: String
         public let password: String
@@ -147,7 +147,6 @@ public enum NetrcError: Error, Equatable {
 }
 
 private enum RegexUtil {
-    @frozen
     fileprivate enum Token: String, CaseIterable {
         case machine, login, password, account, macdef, `default`
 
diff --git a/Sources/_InternalTestSupport/MockArchiver.swift b/Sources/_InternalTestSupport/MockArchiver.swift
index 296f0d413a9..4eecaaadbd8 100644
--- a/Sources/_InternalTestSupport/MockArchiver.swift
+++ b/Sources/_InternalTestSupport/MockArchiver.swift
@@ -13,19 +13,23 @@
 import Basics
 
 package final class MockArchiver: Archiver {
-    package typealias ExtractionHandler = (
+    package typealias ExtractionHandler = @Sendable (
         MockArchiver,
         AbsolutePath,
         AbsolutePath,
         (Result<Void, Error>) -> Void
     ) throws -> Void
-    package typealias CompressionHandler = (
+    package typealias CompressionHandler = @Sendable (
         MockArchiver,
         AbsolutePath,
         AbsolutePath,
         (Result<Void, Error>) -> Void
     ) throws -> Void
-    package typealias ValidationHandler = (MockArchiver, AbsolutePath, (Result<Bool, Error>) -> Void) throws -> Void
+    package typealias ValidationHandler = @Sendable (
+        MockArchiver,
+        AbsolutePath,
+        (Result<Bool, Error>) -> Void
+    ) throws -> Void
 
     package struct Extraction: Equatable {
         public let archivePath: AbsolutePath
diff --git a/Tests/BasicsTests/CancellatorTests.swift b/Tests/BasicsTests/CancellatorTests.swift
index a9ecef35c8f..ed34c03a50c 100644
--- a/Tests/BasicsTests/CancellatorTests.swift
+++ b/Tests/BasicsTests/CancellatorTests.swift
@@ -348,6 +348,7 @@ final class CancellatorTests: XCTestCase {
         struct Worker {
             func work()  {}
 
+            @Sendable
             func cancel() {
                 Thread.sleep(forTimeInterval: 5)
             }
@@ -391,6 +392,7 @@ fileprivate struct Worker {
         return self.semaphore.wait(timeout: deadline)
     }
 
+    @Sendable
     func cancel() {
         print("\(self.name) cancel")
         self.semaphore.signal()
diff --git a/Tests/CommandsTests/PackageRegistryCommandTests.swift b/Tests/CommandsTests/PackageRegistryCommandTests.swift
index 28dcb7c0de4..27578413645 100644
--- a/Tests/CommandsTests/PackageRegistryCommandTests.swift
+++ b/Tests/CommandsTests/PackageRegistryCommandTests.swift
@@ -716,6 +716,7 @@ final class PackageRegistryCommandTests: CommandsTestCase {
             )
         }
 
+        @Sendable
         func validateManifest(
             manifestFile: String,
             in archivePath: AbsolutePath,
diff --git a/Tests/CommandsTests/TestCommandTests.swift b/Tests/CommandsTests/TestCommandTests.swift
index 1d83fb1fa44..fa6cdadaa95 100644
--- a/Tests/CommandsTests/TestCommandTests.swift
+++ b/Tests/CommandsTests/TestCommandTests.swift
@@ -191,7 +191,7 @@ final class TestCommandTests: CommandsTestCase {
         }
 
         try await fixture(name: "Miscellaneous/SkipTests") { fixturePath in
-            let (stdout, stderr) = try await SwiftPM.Test.execute(["--skip", "Tests"], packagePath: fixturePath)
+            let (stdout, _) = try await SwiftPM.Test.execute(["--skip", "Tests"], packagePath: fixturePath)
             // in "swift test" test output goes to stdout
             XCTAssertNoMatch(stdout, .contains("testExample1"))
             XCTAssertNoMatch(stdout, .contains("testExample2"))