1 files changed, 24 insertions, 0 deletions
diff --git a/src/test/ui/impl-trait/auto-trait.stderr b/src/test/ui/impl-trait/auto-trait.stderr
new file mode 100644
index 000000000..5e10272b0
--- /dev/null
+++ b/src/test/ui/impl-trait/auto-trait.stderr
@@ -0,0 +1,24 @@
+error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
+  --> $DIR/auto-trait.rs:21:1
+   |
+LL | impl<T: Send> AnotherTrait for T {}
+   | -------------------------------- first implementation here
+...
+LL | impl AnotherTrait for D<OpaqueType> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `D<OpaqueType>`
+
+error: cannot implement trait on type alias impl trait
+  --> $DIR/auto-trait.rs:21:25
+   |
+LL | impl AnotherTrait for D<OpaqueType> {
+   |                         ^^^^^^^^^^
+   |
+note: type alias impl trait defined here
+  --> $DIR/auto-trait.rs:7:19
+   |
+LL | type OpaqueType = impl OpaqueTrait;
+   |                   ^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0119`.