1 files changed, 19 insertions, 0 deletions

diff --git a/src/test/ui/issues/issue-43355.rs b/src/test/ui/issues/issue-43355.rs
new file mode 100644
index 000000000..bf819af79
--- /dev/null
+++ b/src/test/ui/issues/issue-43355.rs
@@ -0,0 +1,19 @@
+pub trait Trait1<X> {
+    type Output;
+}
+
+pub trait Trait2<X> {}
+
+pub struct A;
+
+impl<X, T> Trait1<X> for T where T: Trait2<X> {
+    type Output = ();
+}
+
+impl<X> Trait1<Box<X>> for A {
+//~^ ERROR conflicting implementations of trait
+//~| downstream crates may implement trait `Trait2<std::boxed::Box<_>>` for type `A`
+    type Output = i32;
+}
+
+fn main() {}