diff --git a/.github/workflows/gh-pages.yml b/.github/workflows/gh-pages.yml
index e0e3a919..cce8b368 100644
--- a/.github/workflows/gh-pages.yml
+++ b/.github/workflows/gh-pages.yml
@@ -8,7 +8,7 @@ on:
 
 jobs:
   deploy:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     concurrency:
       group: ${{ github.workflow }}-${{ github.ref }}
     steps:
diff --git a/SwiftRustIntegrationTestRunner/SwiftRustIntegrationTestRunner/Result.swift b/SwiftRustIntegrationTestRunner/SwiftRustIntegrationTestRunner/Result.swift
index 3549fb6f..48dfad49 100644
--- a/SwiftRustIntegrationTestRunner/SwiftRustIntegrationTestRunner/Result.swift
+++ b/SwiftRustIntegrationTestRunner/SwiftRustIntegrationTestRunner/Result.swift
@@ -6,23 +6,29 @@
 //
 
 func swift_func_takes_callback_with_result_arg(
-    arg: (RustResult<CallbackTestOpaqueRustType, String>) -> ()
+        arg: (RustResult<CallbackTestOpaqueRustType, String>) -> Void
 ) {
-    arg(.Ok(CallbackTestOpaqueRustType(555)))
+        arg(.Ok(CallbackTestOpaqueRustType(555)))
 }
 
 public class ResultTestOpaqueSwiftType {
-    var num: UInt32
-    
-    init(val: UInt32) {
-        self.num = val
-    }
-    
-    func val() -> UInt32 {
-        self.num
-    }
+        var num: UInt32
+
+        init(val: UInt32) {
+                self.num = val
+        }
+
+        func val() -> UInt32 {
+                self.num
+        }
 }
 
+// TODO: we can delete these type assertions once we correctly generate Sendable
+// types. See the following issue:
+// https://github.com/chinedufn/swift-bridge/issues/150
+
+extension AsyncRustFnReturnStruct: @unchecked Sendable {}
+
 extension ResultTestOpaqueRustType: @unchecked Sendable {}
 extension ResultTestOpaqueRustType: Error {}
 
@@ -41,5 +47,7 @@ extension ResultTransparentStruct: Error {}
 extension SameEnum: @unchecked Sendable {}
 extension SameEnum: Error {}
 
+extension AsyncResultOkEnum: @unchecked Sendable {}
+
 extension AsyncResultErrEnum: @unchecked Sendable {}
 extension AsyncResultErrEnum: Error {}
diff --git a/crates/swift-integration-tests/src/async_function.rs b/crates/swift-integration-tests/src/async_function.rs
index d70a778b..5fecc4c8 100644
--- a/crates/swift-integration-tests/src/async_function.rs
+++ b/crates/swift-integration-tests/src/async_function.rs
@@ -13,7 +13,7 @@ mod ffi {
     extern "Rust" {
         async fn rust_async_return_null();
         async fn rust_async_reflect_u8(arg: u8) -> u8;
-        async fn rust_async_reflect_string(string: String) -> String;
+
         async fn rust_async_return_struct() -> AsyncRustFnReturnStruct;
         async fn rust_async_func_reflect_result_opaque_rust(
             arg: Result<AsyncResultOpaqueRustType1, AsyncResultOpaqueRustType2>,
@@ -21,6 +21,8 @@ mod ffi {
         async fn rust_async_func_return_result_null_opaque_rust(
             succeed: bool,
         ) -> Result<(), AsyncResultOpaqueRustType2>;
+
+        async fn rust_async_reflect_string(string: String) -> String;
     }
 
     extern "Rust" {