3 ms·

Exactly. ! for macros was a mistake anyway, I guess that's why they stopped using it with await.

• yakubin 5y ago
  It wasn't. Without "!" it isn't obvious that you cannot take a: let a: Result<u8, u8> = /* whatever *; let b = match a { Ok(v) => Ok(foo(v)), e => e, }; and transform it into: let a: Result<u8, u8> = /* whatever *; let b = a.map(foo); if "foo" is a macro. When you substitute "foo!" for all the "foo" above, it is obvious.
  • simon_o 5y ago
    Perhaps macros shouldn't do things that aren't "obvious" then?
    • infogulch 5y ago
      As a rule, rust rejects the "simpler" choice that instead lay the burden of correctness at the feet of the user. I'm glad they keep a hard line here.
• steveklabnik 5y ago
  > I guess that's why they stopped using it with await await cannot be a macro, it has to be built into the language, and so it doesn't have the ! because it's not one.