(Although I don't think try! is deprecated, is it? Not recommended for sure, but does it print a warning?)

my bad, the warnings appear only on the nightly toolchain

Does it affect generated code?
FYI: rust-lang/rust#62672 (comment)

@niklasad1 can you rebase please? :)

Does it affect generated code?

The binaries are not identical but I benched the following:

pub fn try_operator(a: Result<usize, usize>) -> Result<usize, usize> {
    Ok(a?)
}

pub fn try_macro(a: Result<usize, usize>) -> Result<usize, usize> {
    Ok(r#try!(a))
}

try was ~1 ps faster...... seems to

The binaries are not identical but I benched the following:

pub fn try_operator(a: Result<usize, usize>) -> Result<usize, usize> {
    Ok(a?)
}

pub fn try_macro(a: Result<usize, usize>) -> Result<usize, usize> {
    Ok(r#try!(a))
}

try was ~1 ps faster...... seems to

The problem was with more complex (nested) expressions and the compiler not being able to optimize the overhead away. I think it's fine in our case.