Use more minimized test.

Author: cjgillot

tests/ui/impl-trait/in-trait/late-bound-in-object-assocty.rs

@@ -1,12 +1,12 @@
 // Test for issue #132429
 //@compile-flags: -Zunstable-options --edition=2024
+//@check-pass
 
-trait ThreeCellFragment {
-    fn ext_cells<'a>(
-        &'a self,
-    ) -> dyn core::future::Future<Output = impl IntoIterator<Item = u32>> + 'a {
-        //~^ ERROR mismatched types
-        //~| ERROR return type cannot have an unboxed trait object
+use std::future::Future;
+
+trait Test {
+    fn foo<'a>(&'a self) -> Box<dyn Future<Output = impl IntoIterator<Item = u32>>> {
+        Box::new(async { [] })
     }
 }
 

tests/ui/impl-trait/in-trait/late-bound-in-object-assocty.stderr

@@ -1,32 +0,0 @@
-error[E0308]: mismatched types
-  --> $DIR/late-bound-in-object-assocty.rs:7:80
-   |
-LL |       ) -> dyn core::future::Future<Output = impl IntoIterator<Item = u32>> + 'a {
-   |  ________________________________________________________________________________^
-LL | |
-LL | |
-LL | |     }
-   | |_____^ expected `dyn Future`, found `()`
-   |
-   = note: expected trait object `(dyn Future<Output = _> + 'a)`
-                 found unit type `()`
-
-error[E0746]: return type cannot have an unboxed trait object
-  --> $DIR/late-bound-in-object-assocty.rs:7:10
-   |
-LL |     ) -> dyn core::future::Future<Output = impl IntoIterator<Item = u32>> + 'a {
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
-   |
-help: consider returning an `impl Trait` instead of a `dyn Trait`
-   |
-LL |     ) -> impl core::future::Future<Output = impl IntoIterator<Item = u32>> + 'a {
-   |          ~~~~
-help: alternatively, box the return type, and wrap all of the returned values in `Box::new`
-   |
-LL |     ) -> Box<dyn core::future::Future<Output = impl IntoIterator<Item = u32>> + 'a> {
-   |          ++++                                                                     +
-
-error: aborting due to 2 previous errors
-
-Some errors have detailed explanations: E0308, E0746.
-For more information about an error, try `rustc --explain E0308`.