Show that a test fails on the new solver, too

tests/ui/auto-traits/opaque_type_candidate_selection.next.stderr

@@ -0,0 +1,19 @@
+error[E0119]: conflicting implementations of trait `Trait<_>`
+  --> $DIR/opaque_type_candidate_selection.rs:28:1
+   |
+LL | impl<T> Trait<T> for T {
+   | ---------------------- first implementation here
+...
+LL | impl<T> Trait<T> for defining_scope::Alias<T> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation
+
+error[E0282]: type annotations needed
+  --> $DIR/opaque_type_candidate_selection.rs:11:23
+   |
+LL |     pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
+   |                       ^^^^^^^^^^^^^^^^^^^^^^ cannot infer type
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0119, E0282.
+For more information about an error, try `rustc --explain E0119`.

tests/ui/auto-traits/opaque_type_candidate_selection.stderr → tests/ui/auto-traits/opaque_type_candidate_selection.old.stderr

@@ -1,5 +1,5 @@
 error[E0119]: conflicting implementations of trait `Trait<_>`
-  --> $DIR/opaque_type_candidate_selection.rs:24:1
+  --> $DIR/opaque_type_candidate_selection.rs:28:1
    |
 LL | impl<T> Trait<T> for T {
    | ---------------------- first implementation here

tests/ui/auto-traits/opaque_type_candidate_selection.rs

@@ -1,3 +1,6 @@
+//@revisions: old next
+//@[next] compile-flags: -Znext-solver
+
 //! used to ICE: #119272
 
 #![feature(type_alias_impl_trait)]
@@ -6,6 +9,7 @@ mod defining_scope {
     pub type Alias<T> = impl Sized;
 
     pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
+        //[next]~^ ERROR: type annotations needed
         x
     }
 }