fix internal error for long closure types (#3653)

[rust.git] / tests / target / issue-3651.rs

fn f() -> Box<
    dyn FnMut() -> Thing<
        WithType = LongItemName,
        Error = LONGLONGLONGLONGLONGONGEvenLongerErrorNameLongerLonger,
    >,
> {
}