3 releases (stable)
1.1.0 | Apr 3, 2024 |
---|---|
1.0.0 | Jun 17, 2022 |
0.1.0 | Jun 28, 2021 |
#1282 in Rust patterns
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14KB
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iderive: Inner Derive
iderive
is a drop-in replacement for derive
that doesn't directly depend
on generic bounds. It only checks the types of a struct's fields when deriving
a trait.
Example
#[derive(Clone, Copy)]
struct TaggedIndex<T: ?Sized> {
index: usize,
_tag: PhantomData<T>,
}
let a = TaggedIndex::<String> { index: 0, _tag: PhantomData };
let b = a;
let c = a; // Error: Value used after move
This won't work because derive
requires that T
implements Copy
for
TaggedIndex
to be able to derive it.
In contrast, iderive
only checks the struct's fields to determine if a
trait can be derived. Because usize
and PhantomData<T>
implements Copy
regardless of the type of T
, iderive(Copy)
will implement Copy
for
TaggedIndex
:
#[iderive(Clone, Copy)]
struct TaggedIndex<T: ?Sized> {
index: usize,
_tag: PhantomData<T>,
}
let a = TaggedIndex::<String> { index: 0, _tag: PhantomData };
let b = a;
let c = a; // Works!
Supported traits
iderive
is currently implemented for Clone
, Copy
, Debug
,
Default
, PartialEq
, Eq
, PartialOrd
, Ord
and Hash
.
Dependencies
~0.4–0.8MB
~19K SLoC