]> git.lizzy.rs Git - rust.git/commitdiff
Rollup merge of #70166 - CDirkx:range-inclusive-derives, r=cramertj
authorMazdak Farrokhzad <twingoow@gmail.com>
Sat, 21 Mar 2020 04:33:26 +0000 (05:33 +0100)
committerGitHub <noreply@github.com>
Sat, 21 Mar 2020 04:33:26 +0000 (05:33 +0100)
Derive PartialEq, Eq and Hash for RangeInclusive

The manual implementation of `PartialEq`, `Eq` and `Hash` for `RangeInclusive` was functionally equivalent to a derived implementation.

This change removes the manual implementation and adds the respective derives.
A side effect of this change is that the derives also add implementations for `StructuralPartialEq` and `StructuralEq`, which enables `RangeInclusive` to be used in const generics, closing #70155.

This change is enabled by #68835, which changed the field `is_empty: Option<bool>` to `exhausted: bool` removing the need for *semantic* equality instead of *structural* equality.

## PartialEq
original [`PartialEq`](https://github.com/rust-lang/rust/blob/f4c675c476c18b1a11041193f2f59d695b126bc8/src/libcore/ops/range.rs#L353-L359) implementation:
```rust
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl<Idx: PartialEq> PartialEq for RangeInclusive<Idx> {
    #[inline]
    fn eq(&self, other: &Self) -> bool {
        self.start == other.start && self.end == other.end && self.exhausted == other.exhausted
    }
}
```
expanded derive implementation (using `cargo expand ops::range`):
```rust
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl<Idx> crate::marker::StructuralPartialEq for RangeInclusive<Idx> {}

#[automatically_derived]
#[allow(unused_qualifications)]
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl<Idx: crate::cmp::PartialEq> crate::cmp::PartialEq for RangeInclusive<Idx> {
    #[inline]
    fn eq(&self, other: &RangeInclusive<Idx>) -> bool {
        match *other {
            RangeInclusive { start: ref __self_1_0,end: ref __self_1_1, exhausted: ref __self_1_2 } => match *self {
                RangeInclusive { start: ref __self_0_0, end: ref __self_0_1, exhausted: ref __self_0_2 } => {
                    (*__self_0_0) == (*__self_1_0) && (*__self_0_1) == (*__self_1_1) && (*__self_0_2) == (*__self_1_2)
                }
            },
        }
    }
    #[inline]
    fn ne(&self, other: &RangeInclusive<Idx>) -> bool {
        match *other {
            RangeInclusive { start: ref __self_1_0, end: ref __self_1_1, exhausted: ref __self_1_2 } => match *self {
                RangeInclusive { start: ref __self_0_0, end: ref __self_0_1exhausted: ref __self_0_2 } => {
                    (*__self_0_0) != (*__self_1_0) || (*__self_0_1) != (*__self_1_1) || (*__self_0_2) != (*__self_1_2)
                }
            },
        }
    }
}
```

These implementations both test for *structural* equality, with the same order of field comparisons, and the bound `Idx: PartialEq` is the same.
## Eq
original [`Eq`](https://github.com/rust-lang/rust/blob/f4c675c476c18b1a11041193f2f59d695b126bc8/src/libcore/ops/range.rs#L361-L362) implementation:
```rust
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl<Idx: Eq> Eq for RangeInclusive<Idx> {}
```
expanded derive implementation (using `cargo expand ops::range`):
```rust
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl<Idx> crate::marker::StructuralEq for RangeInclusive<Idx> {}

#[automatically_derived]
#[allow(unused_qualifications)]
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl<Idx: crate::cmp::Eq> crate::cmp::Eq for RangeInclusive<Idx> {
    #[inline]
    #[doc(hidden)]
    fn assert_receiver_is_total_eq(&self) -> () {
        {
            let _: crate::cmp::AssertParamIsEq<Idx>;
            let _: crate::cmp::AssertParamIsEq<Idx>;
            let _: crate::cmp::AssertParamIsEq<bool>;
        }
    }
}
```
These implementations are equivalent since `Eq` is just a marker trait and the bound `Idx: Eq` is the same.

## Hash
original [`Hash`](https://github.com/rust-lang/rust/blob/f4c675c476c18b1a11041193f2f59d695b126bc8/src/libcore/ops/range.rs#L364-L371) implementation:
```rust
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl<Idx: Hash> Hash for RangeInclusive<Idx> {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.start.hash(state);
        self.end.hash(state);
        self.exhausted.hash(state);
    }
}
```
expanded derive implementation (using `cargo expand ops::range`):
```rust
#[automatically_derived]
#[allow(unused_qualifications)]
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl<Idx: crate::hash::Hash> crate::hash::Hash for RangeInclusive<Idx> {
    fn hash<__H: crate::hash::Hasher>(&self, state: &mut __H) -> () {
        match *self { RangeInclusive { start: ref __self_0_0, end: ref __self_0_1, exhausted: ref __self_0_2 } => {
                crate::hash::Hash::hash(&(*__self_0_0), state);
                crate::hash::Hash::hash(&(*__self_0_1), state);
                crate::hash::Hash::hash(&(*__self_0_2), state)
            }
        }
    }
}
```
These implementations are functionally equivalent, with the same order of field hashing, and the bound `Idx: Hash` is the same.


Trivial merge