1 files changed, 29 insertions, 1 deletions
diff --git a/src/tools/clippy/tests/ui/ptr_arg.rs b/src/tools/clippy/tests/ui/ptr_arg.rs
index fd15001e5..5f54101ca 100644
--- a/src/tools/clippy/tests/ui/ptr_arg.rs
+++ b/src/tools/clippy/tests/ui/ptr_arg.rs
@@ -3,7 +3,7 @@
 #![warn(clippy::ptr_arg)]
 
 use std::borrow::Cow;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 fn do_vec(x: &Vec<i64>) {
     //Nothing here
@@ -207,3 +207,31 @@ fn cow_conditional_to_mut(a: &mut Cow<str>) {
         a.to_mut().push_str("foo");
     }
 }
+
+// Issue #9542
+fn dyn_trait_ok(a: &mut Vec<u32>, b: &mut String, c: &mut PathBuf) {
+    trait T {}
+    impl<U> T for Vec<U> {}
+    impl T for String {}
+    impl T for PathBuf {}
+    fn takes_dyn(_: &mut dyn T) {}
+
+    takes_dyn(a);
+    takes_dyn(b);
+    takes_dyn(c);
+}
+
+fn dyn_trait(a: &mut Vec<u32>, b: &mut String, c: &mut PathBuf) {
+    trait T {}
+    impl<U> T for Vec<U> {}
+    impl<U> T for [U] {}
+    impl T for String {}
+    impl T for str {}
+    impl T for PathBuf {}
+    impl T for Path {}
+    fn takes_dyn(_: &mut dyn T) {}
+
+    takes_dyn(a);
+    takes_dyn(b);
+    takes_dyn(c);
+}