Derive PartialEq, Eq and Hash for RangeInclusive

[CDirkx]

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 implementation:

#[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):

#[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 implementation:

#[stable(feature = "inclusive_range", since = "1.26.0")]
impl<Idx: Eq> Eq for RangeInclusive<Idx> {}

expanded derive implementation (using cargo expand ops::range):

#[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 implementation:

#[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):

#[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.

[rust-highfive]

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[rust-highfive]

The job mingw-check of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

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2020-03-19T20:25:51.3552705Z ========================== Starting Command Output ===========================
2020-03-19T20:25:51.3555962Z [command]/bin/bash --noprofile --norc /home/vsts/work/_temp/c6f292c2-bc30-4d40-be11-08d975edf61b.sh
2020-03-19T20:25:51.3556252Z 
2020-03-19T20:25:51.3560449Z ##[section]Finishing: Disable git automatic line ending conversion
2020-03-19T20:25:51.3579475Z ##[section]Starting: Checkout rust-lang/rust@refs/pull/70166/merge to s
2020-03-19T20:25:51.3582680Z Task         : Get sources
2020-03-19T20:25:51.3582987Z Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
2020-03-19T20:25:51.3583287Z Version      : 1.0.0
2020-03-19T20:25:51.3583508Z Author       : Microsoft
---
2020-03-19T20:25:52.3528398Z ##[command]git remote add origin https://github.com/rust-lang/rust
2020-03-19T20:25:52.3533741Z ##[command]git config gc.auto 0
2020-03-19T20:25:52.3537370Z ##[command]git config --get-all http.https://github.com/rust-lang/rust.extraheader
2020-03-19T20:25:52.3540470Z ##[command]git config --get-all http.proxy
2020-03-19T20:25:52.3547331Z ##[command]git -c http.extraheader="AUTHORIZATION: basic ***" fetch --force --tags --prune --progress --no-recurse-submodules --depth=2 origin +refs/heads/*:refs/remotes/origin/* +refs/pull/70166/merge:refs/remotes/pull/70166/merge
---
2020-03-19T20:30:34.6756229Z     Checking core v0.0.0 (/checkout/src/libcore)
2020-03-19T20:30:37.4606346Z error: unused import: `Hasher`
2020-03-19T20:30:37.4607326Z  --> src/libcore/ops/range.rs:2:25
2020-03-19T20:30:37.4608153Z   |
2020-03-19T20:30:37.4608938Z 2 | use crate::hash::{Hash, Hasher};
2020-03-19T20:30:37.4610403Z   |
2020-03-19T20:30:37.4611158Z   = note: `-D unused-imports` implied by `-D warnings`
2020-03-19T20:30:37.4611578Z 
2020-03-19T20:30:41.8147018Z    Compiling libc v0.2.66
---
2020-03-19T20:30:43.9431889Z   local time: Thu Mar 19 20:30:43 UTC 2020
2020-03-19T20:30:44.2355751Z   network time: Thu, 19 Mar 2020 20:30:44 GMT
2020-03-19T20:30:44.2358579Z == end clock drift check ==
2020-03-19T20:30:50.7882457Z 
2020-03-19T20:30:50.7954970Z ##[error]Bash exited with code '1'.
2020-03-19T20:30:50.7969298Z ##[section]Finishing: Run build
2020-03-19T20:30:50.8014055Z ##[section]Starting: Checkout rust-lang/rust@refs/pull/70166/merge to s
2020-03-19T20:30:50.8019368Z Task         : Get sources
2020-03-19T20:30:50.8019692Z Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
2020-03-19T20:30:50.8020017Z Version      : 1.0.0
2020-03-19T20:30:50.8020232Z Author       : Microsoft
2020-03-19T20:30:50.8020232Z Author       : Microsoft
2020-03-19T20:30:50.8020571Z Help         : [More Information](https://go.microsoft.com/fwlink/?LinkId=798199)
2020-03-19T20:30:50.8021154Z ==============================================================================
2020-03-19T20:30:51.1241002Z Cleaning any cached credential from repository: rust-lang/rust (GitHub)
2020-03-19T20:30:51.1285480Z ##[section]Finishing: Checkout rust-lang/rust@refs/pull/70166/merge to s
2020-03-19T20:30:51.1368332Z Cleaning up task key
2020-03-19T20:30:51.1369688Z Start cleaning up orphan processes.
2020-03-19T20:30:51.1545289Z Terminate orphan process: pid (3406) (python)
2020-03-19T20:30:51.1725360Z ##[section]Finishing: Finalize Job

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[cramertj]

@bors r+ rollup

[bors]

📌 Commit 6570e27 has been approved by cramertj

[cuviper]

enables RangeInclusive to be used in const generics, closing #70155.

This should have a test to make sure the implementation doesn't regress.