Test err on impl Trait projection within dyn Trait

Author: cramertj

src/test/ui/impl_trait_projections.rs

@@ -7,7 +7,7 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
-#![feature(conservative_impl_trait, universal_impl_trait)]
+#![feature(dyn_trait, conservative_impl_trait, universal_impl_trait)]
 
 use std::fmt::Debug;
 use std::option;
@@ -40,4 +40,11 @@ fn projection_with_named_trait_inside_path_is_disallowed()
     (1i32..100).next().unwrap()
 }
 
+fn projection_from_impl_trait_inside_dyn_trait_is_disallowed()
+    -> <dyn Iterator<Item = impl Debug> as Iterator>::Item
+//~^ ERROR `impl Trait` is not allowed in path parameters
+{
+    panic!()
+}
+
 fn main() {}

src/test/ui/impl_trait_projections.stderr

@@ -16,6 +16,12 @@ error[E0667]: `impl Trait` is not allowed in path parameters
 37 |     -> <::std::ops::Range<impl Debug> as Iterator>::Item
    |                           ^^^^^^^^^^
 
+error[E0667]: `impl Trait` is not allowed in path parameters
+  --> $DIR/impl_trait_projections.rs:44:29
+   |
+44 |     -> <dyn Iterator<Item = impl Debug> as Iterator>::Item
+   |                             ^^^^^^^^^^
+
 error[E0223]: ambiguous associated type
   --> $DIR/impl_trait_projections.rs:23:50
    |
@@ -24,5 +30,5 @@ error[E0223]: ambiguous associated type
    |
    = note: specify the type using the syntax `<impl std::iter::Iterator as Trait>::Item`
 
-error: aborting due to 4 previous errors
+error: aborting due to 5 previous errors