Add test of lifetime elision on nonconst member
diff --git a/tests/ffi/lib.rs b/tests/ffi/lib.rs
index 10e16a6..32d739d 100644
--- a/tests/ffi/lib.rs
+++ b/tests/ffi/lib.rs
@@ -224,6 +224,7 @@
         fn c_return_borrow(s: &CxxString) -> UniquePtr<Borrow>;
 
         fn const_member(self: &Borrow);
+        fn nonconst_member(self: Pin<&mut Borrow>);
     }
 
     #[repr(u32)]
diff --git a/tests/ffi/tests.cc b/tests/ffi/tests.cc
index d80785d..8ed5456 100644
--- a/tests/ffi/tests.cc
+++ b/tests/ffi/tests.cc
@@ -211,6 +211,8 @@
 
 void Borrow::const_member() const {}
 
+void Borrow::nonconst_member() {}
+
 std::unique_ptr<Borrow> c_return_borrow(const std::string &s) {
   return std::unique_ptr<Borrow>(new Borrow(s));
 }
diff --git a/tests/ffi/tests.h b/tests/ffi/tests.h
index cd265d4..a28c166 100644
--- a/tests/ffi/tests.h
+++ b/tests/ffi/tests.h
@@ -80,6 +80,7 @@
 struct Borrow {
   Borrow(const std::string &s);
   void const_member() const;
+  void nonconst_member();
   const std::string &s;
 };