diff --git a/Cargo.toml b/Cargo.toml
index b256777cc..6ef637988 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,6 +24,9 @@ exclude = [ ".github", "book", "tools" ]
 # where we are depending on such features.
 resolver = "2"
 
+[features]
+arbitrary_self_types = []
+
 [dependencies]
 autocxx-macro = { path="macro", version="0.26.0" }
 cxx = "1.0.78" # ... also needed because expansion of type_id refers to ::cxx
diff --git a/build.rs b/build.rs
index b2de2dc86..637daf464 100644
--- a/build.rs
+++ b/build.rs
@@ -9,6 +9,7 @@
 // It would be nice to use the rustversion crate here instead,
 // but that doesn't work with inner attributes.
 fn main() {
+    println!("cargo::rustc-check-cfg=cfg(nightly)");
     if let Some(ver) = rustc_version() {
         if ver.contains("nightly") {
             println!("cargo:rustc-cfg=nightly")
diff --git a/integration-tests/build.rs b/integration-tests/build.rs
new file mode 100644
index 000000000..e912ac14f
--- /dev/null
+++ b/integration-tests/build.rs
@@ -0,0 +1,12 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    println!("cargo::rustc-check-cfg=cfg(skip_windows_gnu_failing_tests)");
+    println!("cargo::rustc-check-cfg=cfg(skip_windows_msvc_failing_tests)");
+}
diff --git a/src/reference_wrapper.rs b/src/reference_wrapper.rs
index 041bd7277..529f070be 100644
--- a/src/reference_wrapper.rs
+++ b/src/reference_wrapper.rs
@@ -412,7 +412,7 @@ impl<T: ?Sized> CppPin<T> {
         // to
         //   Box<CppPinContents<T>>
         // is safe.
-        let contents = unsafe { std::mem::transmute(item) };
+        let contents = unsafe { std::mem::transmute::<Box<T>, Box<CppPinContents<T>>>(item) };
         Self(contents)
     }