As seen in https://github.com/rust-lang/rust/blob/b9535c0b7d64290b27c4a116262402cd12f77833/tests/ui/associated-type-bounds/return-type-notation/basic.rs. ```rust fn test<T: Foo<method(..): Send>>() {…} ``` https://github.com/rust-lang/rust/pull/109010
