Deref coercion does not work inside braces?

[whatisaphone]

I just found out that deref coercion seemingly doesn't work for an expression inside braces. e.g. &foo works, and &{ foo } doesn't. Full example:

struct One;
struct Two(One);

impl std::ops::Deref for Two {
    type Target = One;
    fn deref(&self) -> &Self::Target { &self.0 }
}

fn hmm(one: &One) {}

fn main() {
    let two = Two(One);
    hmm(&two); // works
    hmm(&{ two }); // doesn't work
}

Playground link

My two questions are:

• What's going on?

• Is there anything I can put inside the braces to stop it from breaking? The real code uses a macro, and I'd like to fix the macro if possible:

  macro_rules! foo {
    () => {{ // <-- these are the pesky braces
      let x = bar();
      // ...
      x
    }}
  }
  
  hmm(&foo!())
  

[jethrogb]

The reference describes coercion but it's not clear from that whether or not your example is supposed to work.

[SkiFire13]

As a workaround, you can force a dereference using the * operator, like &*{ two }