diff --git a/CHANGELOG.md b/CHANGELOG.md
index f8a525c..9b3d7a3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Update `derive_utils` to 0.15. This uses `#[automatically_derived]` on generated impls to improve coverage support.
+
 ## [0.8.6] - 2024-08-23
 
 - Disable `derive` feature of `syn` dependency.
diff --git a/Cargo.toml b/Cargo.toml
index da7db92..6bd293c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -81,7 +81,7 @@ trusted_len = []
 
 # Note: futures, tokio, rayon, serde, and http-body are public dependencies.
 [dependencies]
-derive_utils = "0.14.1"
+derive_utils = "0.15"
 proc-macro2 = "1.0.60"
 quote = "1.0.25"
 syn = { version = "2.0.1", default-features = false, features = ["parsing", "printing", "clone-impls", "proc-macro", "full", "visit-mut"] }
diff --git a/src/enum_derive.rs b/src/enum_derive.rs
index b6fafd1..a24ef97 100644
--- a/src/enum_derive.rs
+++ b/src/enum_derive.rs
@@ -324,7 +324,9 @@ fn expand(args: TokenStream, input: TokenStream) -> Result<TokenStream> {
             const _: () = {
                 trait MustNotImplDrop {}
                 #[allow(clippy::drop_bounds, drop_bounds)]
+                #[automatically_derived]
                 impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+                #[automatically_derived]
                 impl #impl_generics MustNotImplDrop for #name #ty_generics #where_clause {}
             };
         });
diff --git a/tests/expand/enum_derive/example-1.expanded.rs b/tests/expand/enum_derive/example-1.expanded.rs
index f616900..7963e23 100644
--- a/tests/expand/enum_derive/example-1.expanded.rs
+++ b/tests/expand/enum_derive/example-1.expanded.rs
@@ -3,6 +3,7 @@ fn foo(x: i32) -> impl Iterator<Item = i32> {
         __T1(__T1),
         __T2(__T2),
     }
+    #[automatically_derived]
     impl<__T1, __T2> ::core::iter::Iterator for __Enum1<__T1, __T2>
     where
         __T1: ::core::iter::Iterator,
diff --git a/tests/expand/external/futures/async_buf_read.expanded.rs b/tests/expand/external/futures/async_buf_read.expanded.rs
index dd97f3e..446cb3a 100644
--- a/tests/expand/external/futures/async_buf_read.expanded.rs
+++ b/tests/expand/external/futures/async_buf_read.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::futures::io::AsyncBufRead for Enum<A, B>
 where
     A: ::futures::io::AsyncBufRead,
@@ -51,6 +52,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -59,7 +61,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/external/futures/async_read.expanded.rs b/tests/expand/external/futures/async_read.expanded.rs
index c0c48a9..01dd58c 100644
--- a/tests/expand/external/futures/async_read.expanded.rs
+++ b/tests/expand/external/futures/async_read.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::futures::io::AsyncRead for Enum<A, B>
 where
     A: ::futures::io::AsyncRead,
@@ -60,6 +61,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -68,7 +70,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/external/futures/async_seek.expanded.rs b/tests/expand/external/futures/async_seek.expanded.rs
index cdd8f47..4e443f7 100644
--- a/tests/expand/external/futures/async_seek.expanded.rs
+++ b/tests/expand/external/futures/async_seek.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::futures::io::AsyncSeek for Enum<A, B>
 where
     A: ::futures::io::AsyncSeek,
@@ -35,6 +36,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -43,7 +45,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/external/futures/async_write.expanded.rs b/tests/expand/external/futures/async_write.expanded.rs
index c3b23ed..4e76cef 100644
--- a/tests/expand/external/futures/async_write.expanded.rs
+++ b/tests/expand/external/futures/async_write.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::futures::io::AsyncWrite for Enum<A, B>
 where
     A: ::futures::io::AsyncWrite,
@@ -104,6 +105,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -112,7 +114,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/external/futures/sink.expanded.rs b/tests/expand/external/futures/sink.expanded.rs
index 3250c14..7943008 100644
--- a/tests/expand/external/futures/sink.expanded.rs
+++ b/tests/expand/external/futures/sink.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B, __Item> ::futures::sink::Sink<__Item> for Enum<A, B>
 where
     A: ::futures::sink::Sink<__Item>,
@@ -94,6 +95,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -102,7 +104,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/external/futures/stream.expanded.rs b/tests/expand/external/futures/stream.expanded.rs
index 6e118c3..8c03e7d 100644
--- a/tests/expand/external/futures/stream.expanded.rs
+++ b/tests/expand/external/futures/stream.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::futures::stream::Stream for Enum<A, B>
 where
     A: ::futures::stream::Stream,
@@ -40,6 +41,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -48,7 +50,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/external/http_body/body.expanded.rs b/tests/expand/external/http_body/body.expanded.rs
index e313446..864334f 100644
--- a/tests/expand/external/http_body/body.expanded.rs
+++ b/tests/expand/external/http_body/body.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::http_body::Body for Enum<A, B>
 where
     A: ::http_body::Body,
@@ -54,6 +55,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -62,7 +64,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/external/rayon/indexed_parallel_iterator.expanded.rs b/tests/expand/external/rayon/indexed_parallel_iterator.expanded.rs
index 9df9adc..c910ee1 100644
--- a/tests/expand/external/rayon/indexed_parallel_iterator.expanded.rs
+++ b/tests/expand/external/rayon/indexed_parallel_iterator.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::rayon::iter::ParallelIterator for Enum<A, B>
 where
     A: ::rayon::iter::ParallelIterator,
@@ -34,6 +35,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::rayon::iter::IndexedParallelIterator for Enum<A, B>
 where
     A: ::rayon::iter::IndexedParallelIterator,
diff --git a/tests/expand/external/rayon/parallel_extend.expanded.rs b/tests/expand/external/rayon/parallel_extend.expanded.rs
index f238a79..a3ca232 100644
--- a/tests/expand/external/rayon/parallel_extend.expanded.rs
+++ b/tests/expand/external/rayon/parallel_extend.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B, __T: Send> ::rayon::iter::ParallelExtend<__T> for Enum<A, B>
 where
     A: ::rayon::iter::ParallelExtend<__T>,
diff --git a/tests/expand/external/rayon/parallel_iterator.expanded.rs b/tests/expand/external/rayon/parallel_iterator.expanded.rs
index 92c7d21..43ab0e3 100644
--- a/tests/expand/external/rayon/parallel_iterator.expanded.rs
+++ b/tests/expand/external/rayon/parallel_iterator.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::rayon::iter::ParallelIterator for Enum<A, B>
 where
     A: ::rayon::iter::ParallelIterator,
diff --git a/tests/expand/external/serde/serialize.expanded.rs b/tests/expand/external/serde/serialize.expanded.rs
index 9b4ea74..a34751f 100644
--- a/tests/expand/external/serde/serialize.expanded.rs
+++ b/tests/expand/external/serde/serialize.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::serde::ser::Serialize for Enum<A, B>
 where
     A: ::serde::ser::Serialize,
diff --git a/tests/expand/external/tokio/async_buf_read.expanded.rs b/tests/expand/external/tokio/async_buf_read.expanded.rs
index 0003659..6ee6d3e 100644
--- a/tests/expand/external/tokio/async_buf_read.expanded.rs
+++ b/tests/expand/external/tokio/async_buf_read.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::tokio::io::AsyncBufRead for Enum<A, B>
 where
     A: ::tokio::io::AsyncBufRead,
@@ -49,6 +50,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -57,7 +59,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/external/tokio/async_read.expanded.rs b/tests/expand/external/tokio/async_read.expanded.rs
index 343c4ab..ebdb12c 100644
--- a/tests/expand/external/tokio/async_read.expanded.rs
+++ b/tests/expand/external/tokio/async_read.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::tokio::io::AsyncRead for Enum<A, B>
 where
     A: ::tokio::io::AsyncRead,
@@ -34,6 +35,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -42,7 +44,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/external/tokio/async_seek.expanded.rs b/tests/expand/external/tokio/async_seek.expanded.rs
index f916d82..7301d06 100644
--- a/tests/expand/external/tokio/async_seek.expanded.rs
+++ b/tests/expand/external/tokio/async_seek.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::tokio::io::AsyncSeek for Enum<A, B>
 where
     A: ::tokio::io::AsyncSeek,
@@ -52,6 +53,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -60,7 +62,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/external/tokio/async_write.expanded.rs b/tests/expand/external/tokio/async_write.expanded.rs
index 679d940..957a61c 100644
--- a/tests/expand/external/tokio/async_write.expanded.rs
+++ b/tests/expand/external/tokio/async_write.expanded.rs
@@ -4,6 +4,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::tokio::io::AsyncWrite for Enum<A, B>
 where
     A: ::tokio::io::AsyncWrite,
@@ -106,6 +107,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -114,7 +116,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/std/debug.expanded.rs b/tests/expand/std/debug.expanded.rs
index e0725c9..2fdfb86 100644
--- a/tests/expand/std/debug.expanded.rs
+++ b/tests/expand/std/debug.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::core::fmt::Debug for Enum<A, B>
 where
     A: ::core::fmt::Debug,
diff --git a/tests/expand/std/error.expanded.rs b/tests/expand/std/error.expanded.rs
index e169bcd..8c41daf 100644
--- a/tests/expand/std/error.expanded.rs
+++ b/tests/expand/std/error.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::core::fmt::Display for Enum<A, B>
 where
     A: ::core::fmt::Display,
@@ -16,6 +17,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::fmt::Debug for Enum<A, B>
 where
     A: ::core::fmt::Debug,
@@ -29,6 +31,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::std::error::Error for Enum<A, B>
 where
     A: ::std::error::Error,
diff --git a/tests/expand/std/future.expanded.rs b/tests/expand/std/future.expanded.rs
index f9b8ca8..d2af107 100644
--- a/tests/expand/std/future.expanded.rs
+++ b/tests/expand/std/future.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::core::future::Future for Enum<A, B>
 where
     A: ::core::future::Future,
@@ -32,6 +33,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::marker::Unpin for Enum<A, B>
 where
     A: ::core::marker::Unpin,
@@ -40,7 +42,9 @@ where
 const _: () = {
     trait MustNotImplDrop {}
     #[allow(clippy::drop_bounds, drop_bounds)]
+    #[automatically_derived]
     impl<T: ::core::ops::Drop> MustNotImplDrop for T {}
+    #[automatically_derived]
     impl<A, B> MustNotImplDrop for Enum<A, B> {}
 };
 fn main() {}
diff --git a/tests/expand/std/io/buf_read.expanded.rs b/tests/expand/std/io/buf_read.expanded.rs
index 97844ab..ea68b82 100644
--- a/tests/expand/std/io/buf_read.expanded.rs
+++ b/tests/expand/std/io/buf_read.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::std::io::Read for Enum<A, B>
 where
     A: ::std::io::Read,
@@ -53,6 +54,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::std::io::BufRead for Enum<A, B>
 where
     A: ::std::io::BufRead,
diff --git a/tests/expand/std/io/read.expanded.rs b/tests/expand/std/io/read.expanded.rs
index 8f6b727..fb06bf5 100644
--- a/tests/expand/std/io/read.expanded.rs
+++ b/tests/expand/std/io/read.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::std::io::Read for Enum<A, B>
 where
     A: ::std::io::Read,
diff --git a/tests/expand/std/io/seek.expanded.rs b/tests/expand/std/io/seek.expanded.rs
index f6acda3..d06f825 100644
--- a/tests/expand/std/io/seek.expanded.rs
+++ b/tests/expand/std/io/seek.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::std::io::Seek for Enum<A, B>
 where
     A: ::std::io::Seek,
diff --git a/tests/expand/std/io/write.expanded.rs b/tests/expand/std/io/write.expanded.rs
index b8b7745..e742561 100644
--- a/tests/expand/std/io/write.expanded.rs
+++ b/tests/expand/std/io/write.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::std::io::Write for Enum<A, B>
 where
     A: ::std::io::Write,
diff --git a/tests/expand/std/iter/double_ended_iterator.expanded.rs b/tests/expand/std/iter/double_ended_iterator.expanded.rs
index ffd1634..adbf825 100644
--- a/tests/expand/std/iter/double_ended_iterator.expanded.rs
+++ b/tests/expand/std/iter/double_ended_iterator.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::core::iter::Iterator for Enum<A, B>
 where
     A: ::core::iter::Iterator,
@@ -124,6 +125,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::iter::DoubleEndedIterator for Enum<A, B>
 where
     A: ::core::iter::DoubleEndedIterator,
diff --git a/tests/expand/std/iter/exact_size_iterator.expanded.rs b/tests/expand/std/iter/exact_size_iterator.expanded.rs
index 50c3f41..97a5507 100644
--- a/tests/expand/std/iter/exact_size_iterator.expanded.rs
+++ b/tests/expand/std/iter/exact_size_iterator.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::core::iter::Iterator for Enum<A, B>
 where
     A: ::core::iter::Iterator,
@@ -124,6 +125,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::iter::ExactSizeIterator for Enum<A, B>
 where
     A: ::core::iter::ExactSizeIterator,
diff --git a/tests/expand/std/iter/extend.expanded.rs b/tests/expand/std/iter/extend.expanded.rs
index b0072b6..4fc2536 100644
--- a/tests/expand/std/iter/extend.expanded.rs
+++ b/tests/expand/std/iter/extend.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B, __A> ::core::iter::Extend<__A> for Enum<A, B>
 where
     A: ::core::iter::Extend<__A>,
diff --git a/tests/expand/std/iter/fused_iterator.expanded.rs b/tests/expand/std/iter/fused_iterator.expanded.rs
index 576eab0..761e61b 100644
--- a/tests/expand/std/iter/fused_iterator.expanded.rs
+++ b/tests/expand/std/iter/fused_iterator.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::core::iter::Iterator for Enum<A, B>
 where
     A: ::core::iter::Iterator,
@@ -124,6 +125,7 @@ where
         }
     }
 }
+#[automatically_derived]
 impl<A, B> ::core::iter::FusedIterator for Enum<A, B>
 where
     A: ::core::iter::FusedIterator,
diff --git a/tests/expand/std/iter/iterator.expanded.rs b/tests/expand/std/iter/iterator.expanded.rs
index 20354a8..2ba5092 100644
--- a/tests/expand/std/iter/iterator.expanded.rs
+++ b/tests/expand/std/iter/iterator.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::core::iter::Iterator for Enum<A, B>
 where
     A: ::core::iter::Iterator,
diff --git a/tests/expand/std/iter/trusted_len.expanded.rs b/tests/expand/std/iter/trusted_len.expanded.rs
index e70a373..1069ef6 100644
--- a/tests/expand/std/iter/trusted_len.expanded.rs
+++ b/tests/expand/std/iter/trusted_len.expanded.rs
@@ -3,6 +3,7 @@ enum Enum<A, B> {
     A(A),
     B(B),
 }
+#[automatically_derived]
 impl<A, B> ::core::iter::Iterator for Enum<A, B>
 where
     A: ::core::iter::Iterator,
@@ -124,6 +125,7 @@ where
         }
     }
 }
+#[automatically_derived]
 unsafe impl<A, B> ::core::iter::TrustedLen for Enum<A, B>
 where
     A: ::core::iter::TrustedLen,