Macro default 

default!() { /* proc-macro */ }

Impl filler: Generates a dummy implementation that returns Default::default() in all associated constants and functions.

Example

// Constant defaults require the `const_default_impls` feature
#![cfg_attr(feature = "const-default-impls", feature(const_default_impls))]

#[portrait::make]
trait Foo {
    fn qux() -> u64;

    #[cfg(feature = "const-default-impls")]
    const BAR: i32;
}

struct Corge;

#[portrait::fill(portrait::default)]
impl Foo for Corge {}

assert_eq!(Corge::qux(), 0u64);

#[cfg(feature = "const-default-impls")]
assert_eq!(Corge::BAR, 0i32);