Rustdoc not showing return type but showing return type lifetimes

[bjorn3]

https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/interpret/struct.Memory.html#method.allocations

[FanShupei]

It seems the nightly rustdoc cannot handle impl Trait well. It works in argument position, not in return position.

I tried with a minimal examle. Create a new lib project, and write following in lib.rs, then cargo doc.

pub fn f(x: impl Copy) -> impl Copy {
    1
}

The output is weird. The return type vanishes.

pub fn f(x: impl Copy) -> 

rustdoc vesion: rustdoc 1.29.0-nightly (254f879 2018-07-13)
toolchain: nightly-x86_64-unknown-linux-gnu

[GuillaumeGomez]

Fixed in #53541.