Merge pull request #676 from mcarton/hash_eq

Make DERIVE_HASH_NOT_EQ symmetric
This commit is contained in:
Manish Goregaokar 2016-02-16 05:20:30 +05:30
commit 09ef38b30b
4 changed files with 42 additions and 15 deletions

View file

@ -33,7 +33,7 @@ name
[collapsible_if](https://github.com/Manishearth/rust-clippy/wiki#collapsible_if) | warn | two nested `if`-expressions can be collapsed into one, e.g. `if x { if y { foo() } }` can be written as `if x && y { foo() }` and an `else { if .. } expression can be collapsed to `else if` [collapsible_if](https://github.com/Manishearth/rust-clippy/wiki#collapsible_if) | warn | two nested `if`-expressions can be collapsed into one, e.g. `if x { if y { foo() } }` can be written as `if x && y { foo() }` and an `else { if .. } expression can be collapsed to `else if`
[cyclomatic_complexity](https://github.com/Manishearth/rust-clippy/wiki#cyclomatic_complexity) | warn | finds functions that should be split up into multiple functions [cyclomatic_complexity](https://github.com/Manishearth/rust-clippy/wiki#cyclomatic_complexity) | warn | finds functions that should be split up into multiple functions
[deprecated_semver](https://github.com/Manishearth/rust-clippy/wiki#deprecated_semver) | warn | `Warn` on `#[deprecated(since = "x")]` where x is not semver [deprecated_semver](https://github.com/Manishearth/rust-clippy/wiki#deprecated_semver) | warn | `Warn` on `#[deprecated(since = "x")]` where x is not semver
[derive_hash_not_eq](https://github.com/Manishearth/rust-clippy/wiki#derive_hash_not_eq) | warn | deriving `Hash` but implementing `PartialEq` explicitly [derive_hash_xor_eq](https://github.com/Manishearth/rust-clippy/wiki#derive_hash_xor_eq) | warn | deriving `Hash` but implementing `PartialEq` explicitly
[drop_ref](https://github.com/Manishearth/rust-clippy/wiki#drop_ref) | warn | call to `std::mem::drop` with a reference instead of an owned value, which will not call the `Drop::drop` method on the underlying value [drop_ref](https://github.com/Manishearth/rust-clippy/wiki#drop_ref) | warn | call to `std::mem::drop` with a reference instead of an owned value, which will not call the `Drop::drop` method on the underlying value
[duplicate_underscore_argument](https://github.com/Manishearth/rust-clippy/wiki#duplicate_underscore_argument) | warn | Function arguments having names which only differ by an underscore [duplicate_underscore_argument](https://github.com/Manishearth/rust-clippy/wiki#duplicate_underscore_argument) | warn | Function arguments having names which only differ by an underscore
[empty_loop](https://github.com/Manishearth/rust-clippy/wiki#empty_loop) | warn | empty `loop {}` detected [empty_loop](https://github.com/Manishearth/rust-clippy/wiki#empty_loop) | warn | empty `loop {}` detected

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@ -32,7 +32,7 @@ use utils::{match_path, span_lint_and_then};
/// } /// }
/// ``` /// ```
declare_lint! { declare_lint! {
pub DERIVE_HASH_NOT_EQ, pub DERIVE_HASH_XOR_EQ,
Warn, Warn,
"deriving `Hash` but implementing `PartialEq` explicitly" "deriving `Hash` but implementing `PartialEq` explicitly"
} }
@ -65,7 +65,7 @@ pub struct Derive;
impl LintPass for Derive { impl LintPass for Derive {
fn get_lints(&self) -> LintArray { fn get_lints(&self) -> LintArray {
lint_array!(EXPL_IMPL_CLONE_ON_COPY, DERIVE_HASH_NOT_EQ) lint_array!(EXPL_IMPL_CLONE_ON_COPY, DERIVE_HASH_XOR_EQ)
} }
} }
@ -75,19 +75,25 @@ impl LateLintPass for Derive {
let ItemImpl(_, _, _, Some(ref trait_ref), _, _) = item.node let ItemImpl(_, _, _, Some(ref trait_ref), _, _) = item.node
], { ], {
let ty = cx.tcx.lookup_item_type(cx.tcx.map.local_def_id(item.id)).ty; let ty = cx.tcx.lookup_item_type(cx.tcx.map.local_def_id(item.id)).ty;
if item.attrs.iter().any(is_automatically_derived) { let is_automatically_derived = item.attrs.iter().any(is_automatically_derived);
check_hash_peq(cx, item.span, trait_ref, ty);
} check_hash_peq(cx, item.span, trait_ref, ty, is_automatically_derived);
else {
if !is_automatically_derived {
check_copy_clone(cx, item, trait_ref, ty); check_copy_clone(cx, item, trait_ref, ty);
} }
}} }}
} }
} }
/// Implementation of the `DERIVE_HASH_NOT_EQ` lint. /// Implementation of the `DERIVE_HASH_XOR_EQ` lint.
fn check_hash_peq(cx: &LateContext, span: Span, trait_ref: &TraitRef, ty: ty::Ty) { fn check_hash_peq(
// If `item` is an automatically derived `Hash` implementation cx: &LateContext,
span: Span,
trait_ref: &TraitRef,
ty: ty::Ty,
hash_is_automatically_derived: bool
) {
if_let_chain! {[ if_let_chain! {[
match_path(&trait_ref.path, &HASH_PATH), match_path(&trait_ref.path, &HASH_PATH),
let Some(peq_trait_def_id) = cx.tcx.lang_items.eq_trait() let Some(peq_trait_def_id) = cx.tcx.lang_items.eq_trait()
@ -103,14 +109,25 @@ fn check_hash_peq(cx: &LateContext, span: Span, trait_ref: &TraitRef, ty: ty::Ty
let Some(impl_ids) = peq_impls.get(&simpl_ty) let Some(impl_ids) = peq_impls.get(&simpl_ty)
], { ], {
for &impl_id in impl_ids { for &impl_id in impl_ids {
let peq_is_automatically_derived = cx.tcx.get_attrs(impl_id).iter().any(is_automatically_derived);
if peq_is_automatically_derived == hash_is_automatically_derived {
return;
}
let trait_ref = cx.tcx.impl_trait_ref(impl_id).expect("must be a trait implementation"); let trait_ref = cx.tcx.impl_trait_ref(impl_id).expect("must be a trait implementation");
// Only care about `impl PartialEq<Foo> for Foo` // Only care about `impl PartialEq<Foo> for Foo`
if trait_ref.input_types()[0] == ty && if trait_ref.input_types()[0] == ty {
!cx.tcx.get_attrs(impl_id).iter().any(is_automatically_derived) { let mess = if peq_is_automatically_derived {
"you are implementing `Hash` explicitly but have derived `PartialEq`"
} else {
"you are deriving `Hash` but have implemented `PartialEq` explicitly"
};
span_lint_and_then( span_lint_and_then(
cx, DERIVE_HASH_NOT_EQ, span, cx, DERIVE_HASH_XOR_EQ, span,
"you are deriving `Hash` but have implemented `PartialEq` explicitly", mess,
|db| { |db| {
if let Some(node_id) = cx.tcx.map.as_local_node_id(impl_id) { if let Some(node_id) = cx.tcx.map.as_local_node_id(impl_id) {
db.span_note( db.span_note(

View file

@ -198,7 +198,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
copies::IFS_SAME_COND, copies::IFS_SAME_COND,
copies::MATCH_SAME_ARMS, copies::MATCH_SAME_ARMS,
cyclomatic_complexity::CYCLOMATIC_COMPLEXITY, cyclomatic_complexity::CYCLOMATIC_COMPLEXITY,
derive::DERIVE_HASH_NOT_EQ, derive::DERIVE_HASH_XOR_EQ,
derive::EXPL_IMPL_CLONE_ON_COPY, derive::EXPL_IMPL_CLONE_ON_COPY,
drop_ref::DROP_REF, drop_ref::DROP_REF,
entry::MAP_ENTRY, entry::MAP_ENTRY,

View file

@ -4,6 +4,8 @@
#![deny(warnings)] #![deny(warnings)]
#![allow(dead_code)] #![allow(dead_code)]
use std::hash::{Hash, Hasher};
#[derive(PartialEq, Hash)] #[derive(PartialEq, Hash)]
struct Foo; struct Foo;
@ -27,6 +29,14 @@ impl PartialEq<Baz> for Baz {
fn eq(&self, _: &Baz) -> bool { true } fn eq(&self, _: &Baz) -> bool { true }
} }
#[derive(PartialEq)]
struct Bah;
impl Hash for Bah {
//~^ ERROR you are implementing `Hash` explicitly but have derived `PartialEq`
fn hash<H: Hasher>(&self, _: &mut H) {}
}
#[derive(Copy)] #[derive(Copy)]
struct Qux; struct Qux;