diff --git a/tests/derive_arc/successes/assoc_function_rettype.rs b/tests/derive_arc/successes/assoc_function_rettype.rs
new file mode 100644
index 0000000..ccf14d7
--- /dev/null
+++ b/tests/derive_arc/successes/assoc_function_rettype.rs
@@ -0,0 +1,21 @@
+use blanket::blanket;
+use impls::impls;
+
+use std::sync::Arc;
+
+#[blanket(derive(Arc))]
+pub trait StaticChecker {
+    fn check() -> Result<(), String>;
+}
+
+#[derive(Default)]
+struct NoOpChecker;
+
+impl StaticChecker for NoOpChecker {
+    fn check() -> Result<(), String> { Ok(()) }
+}
+
+fn main() {
+    assert!(impls!(    NoOpChecker:  StaticChecker));
+    assert!(impls!(Arc<NoOpChecker>: StaticChecker));
+}
diff --git a/tests/derive_box/successes/assoc_function_rettype.rs b/tests/derive_box/successes/assoc_function_rettype.rs
new file mode 100644
index 0000000..b06e0a5
--- /dev/null
+++ b/tests/derive_box/successes/assoc_function_rettype.rs
@@ -0,0 +1,19 @@
+use blanket::blanket;
+use impls::impls;
+
+#[blanket(derive(Box))]
+pub trait StaticChecker {
+    fn check() -> Result<(), String>;
+}
+
+#[derive(Default)]
+struct NoOpChecker;
+
+impl StaticChecker for NoOpChecker {
+    fn check() -> Result<(), String> { Ok(()) }
+}
+
+fn main() {
+    assert!(impls!(    NoOpChecker:  StaticChecker));
+    assert!(impls!(Box<NoOpChecker>: StaticChecker));
+}
diff --git a/tests/derive_mut/successes/assoc_function_rettype.rs b/tests/derive_mut/successes/assoc_function_rettype.rs
new file mode 100644
index 0000000..1bb8fa3
--- /dev/null
+++ b/tests/derive_mut/successes/assoc_function_rettype.rs
@@ -0,0 +1,19 @@
+use blanket::blanket;
+use impls::impls;
+
+#[blanket(derive(Mut))]
+pub trait StaticChecker {
+    fn check() -> Result<(), String>;
+}
+
+#[derive(Default)]
+struct NoOpChecker;
+
+impl StaticChecker for NoOpChecker {
+    fn check() -> Result<(), String> { Ok(()) }
+}
+
+fn main() {
+    assert!(impls!(     NoOpChecker:  StaticChecker));
+    assert!(impls!(&mut NoOpChecker: StaticChecker));
+}
diff --git a/tests/derive_rc/successes/assoc_function_rettype.rs b/tests/derive_rc/successes/assoc_function_rettype.rs
new file mode 100644
index 0000000..5625247
--- /dev/null
+++ b/tests/derive_rc/successes/assoc_function_rettype.rs
@@ -0,0 +1,21 @@
+use blanket::blanket;
+use impls::impls;
+
+use std::rc::Rc;
+
+#[blanket(derive(Rc))]
+pub trait StaticChecker {
+    fn check() -> Result<(), String>;
+}
+
+#[derive(Default)]
+struct NoOpChecker;
+
+impl StaticChecker for NoOpChecker {
+    fn check() -> Result<(), String> { Ok(()) }
+}
+
+fn main() {
+    assert!(impls!(   NoOpChecker:  StaticChecker));
+    assert!(impls!(Rc<NoOpChecker>: StaticChecker));
+}
diff --git a/tests/derive_ref/successes/assoc_function_rettype.rs b/tests/derive_ref/successes/assoc_function_rettype.rs
new file mode 100644
index 0000000..fd5dca5
--- /dev/null
+++ b/tests/derive_ref/successes/assoc_function_rettype.rs
@@ -0,0 +1,19 @@
+use blanket::blanket;
+use impls::impls;
+
+#[blanket(derive(Ref))]
+pub trait StaticChecker {
+    fn check() -> Result<(), String>;
+}
+
+#[derive(Default)]
+struct NoOpChecker;
+
+impl StaticChecker for NoOpChecker {
+    fn check() -> Result<(), String> { Ok(()) }
+}
+
+fn main() {
+    assert!(impls!( NoOpChecker:  StaticChecker));
+    assert!(impls!(&NoOpChecker: StaticChecker));
+}