--- /dev/null
+error[E0658]: type alias impl trait is not permitted here
+ --> $DIR/issue-53678-generator-and-const-fn.rs:20:36
+ |
+LL | const FOO: GenOnce<usize, usize> = const_generator(10, 100);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: see issue #63065 <https://github.com/rust-lang/rust/issues/63065> for more information
+ = help: add `#![feature(impl_trait_in_bindings)]` to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.