Auto merge of #8869 - Jarcho:derive_partial_eq_without_eq, r=flip1995

Set correct `ParamEnv` for `derive_partial_eq_without_eq`

fixes #8867

changelog: Handle differing predicates applied by `#[derive(PartialEq)]` and `#[derive(Eq)]` in `derive_partial_eq_without_eq`
This commit is contained in:
bors 2022-06-01 19:27:54 +00:00
commit 7572b6b757
4 changed files with 67 additions and 14 deletions

View file

@ -1,16 +1,17 @@
use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_note, span_lint_and_sugg, span_lint_and_then};
use clippy_utils::paths;
use clippy_utils::ty::{implements_trait, is_copy};
use clippy_utils::ty::{implements_trait, implements_trait_with_env, is_copy};
use clippy_utils::{is_lint_allowed, match_def_path};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::intravisit::{walk_expr, walk_fn, walk_item, FnKind, Visitor};
use rustc_hir::{
BlockCheckMode, BodyId, Expr, ExprKind, FnDecl, HirId, Impl, Item, ItemKind, TraitRef, UnsafeSource, Unsafety,
self as hir, BlockCheckMode, BodyId, Expr, ExprKind, FnDecl, HirId, Impl, Item, ItemKind, UnsafeSource, Unsafety,
};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::hir::nested_filter;
use rustc_middle::ty::{self, Ty};
use rustc_middle::ty::subst::GenericArg;
use rustc_middle::ty::{self, BoundConstness, ImplPolarity, ParamEnv, PredicateKind, TraitPredicate, TraitRef, Ty};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::source_map::Span;
use rustc_span::sym;
@ -224,7 +225,7 @@ impl<'tcx> LateLintPass<'tcx> for Derive {
fn check_hash_peq<'tcx>(
cx: &LateContext<'tcx>,
span: Span,
trait_ref: &TraitRef<'_>,
trait_ref: &hir::TraitRef<'_>,
ty: Ty<'tcx>,
hash_is_automatically_derived: bool,
) {
@ -277,7 +278,7 @@ fn check_hash_peq<'tcx>(
fn check_ord_partial_ord<'tcx>(
cx: &LateContext<'tcx>,
span: Span,
trait_ref: &TraitRef<'_>,
trait_ref: &hir::TraitRef<'_>,
ty: Ty<'tcx>,
ord_is_automatically_derived: bool,
) {
@ -328,7 +329,7 @@ fn check_ord_partial_ord<'tcx>(
}
/// Implementation of the `EXPL_IMPL_CLONE_ON_COPY` lint.
fn check_copy_clone<'tcx>(cx: &LateContext<'tcx>, item: &Item<'_>, trait_ref: &TraitRef<'_>, ty: Ty<'tcx>) {
fn check_copy_clone<'tcx>(cx: &LateContext<'tcx>, item: &Item<'_>, trait_ref: &hir::TraitRef<'_>, ty: Ty<'tcx>) {
let clone_id = match cx.tcx.lang_items().clone_trait() {
Some(id) if trait_ref.trait_def_id() == Some(id) => id,
_ => return,
@ -378,7 +379,7 @@ fn check_copy_clone<'tcx>(cx: &LateContext<'tcx>, item: &Item<'_>, trait_ref: &T
fn check_unsafe_derive_deserialize<'tcx>(
cx: &LateContext<'tcx>,
item: &Item<'_>,
trait_ref: &TraitRef<'_>,
trait_ref: &hir::TraitRef<'_>,
ty: Ty<'tcx>,
) {
fn has_unsafe<'tcx>(cx: &LateContext<'tcx>, item: &'tcx Item<'_>) -> bool {
@ -455,13 +456,41 @@ impl<'tcx> Visitor<'tcx> for UnsafeVisitor<'_, 'tcx> {
}
/// Implementation of the `DERIVE_PARTIAL_EQ_WITHOUT_EQ` lint.
fn check_partial_eq_without_eq<'tcx>(cx: &LateContext<'tcx>, span: Span, trait_ref: &TraitRef<'_>, ty: Ty<'tcx>) {
fn check_partial_eq_without_eq<'tcx>(cx: &LateContext<'tcx>, span: Span, trait_ref: &hir::TraitRef<'_>, ty: Ty<'tcx>) {
if_chain! {
if let ty::Adt(adt, substs) = ty.kind();
if let Some(eq_trait_def_id) = cx.tcx.get_diagnostic_item(sym::Eq);
if let Some(peq_trait_def_id) = cx.tcx.get_diagnostic_item(sym::PartialEq);
if let Some(def_id) = trait_ref.trait_def_id();
if cx.tcx.is_diagnostic_item(sym::PartialEq, def_id);
if !implements_trait(cx, ty, eq_trait_def_id, substs);
// New `ParamEnv` replacing `T: PartialEq` with `T: Eq`
let param_env = ParamEnv::new(
cx.tcx.mk_predicates(cx.param_env.caller_bounds().iter().map(|p| {
let kind = p.kind();
match kind.skip_binder() {
PredicateKind::Trait(p)
if p.trait_ref.def_id == peq_trait_def_id
&& p.trait_ref.substs.get(0) == p.trait_ref.substs.get(1)
&& matches!(p.trait_ref.self_ty().kind(), ty::Param(_))
&& p.constness == BoundConstness::NotConst
&& p.polarity == ImplPolarity::Positive =>
{
cx.tcx.mk_predicate(kind.rebind(PredicateKind::Trait(TraitPredicate {
trait_ref: TraitRef::new(
eq_trait_def_id,
cx.tcx.mk_substs([GenericArg::from(p.trait_ref.self_ty())].into_iter()),
),
constness: BoundConstness::NotConst,
polarity: ImplPolarity::Positive,
})))
},
_ => p,
}
})),
cx.param_env.reveal(),
cx.param_env.constness(),
);
if !implements_trait_with_env(cx.tcx, param_env, ty, eq_trait_def_id, substs);
then {
// If all of our fields implement `Eq`, we can implement `Eq` too
for variant in adt.variants() {

View file

@ -13,7 +13,8 @@ use rustc_lint::LateContext;
use rustc_middle::mir::interpret::{ConstValue, Scalar};
use rustc_middle::ty::subst::{GenericArg, GenericArgKind, Subst};
use rustc_middle::ty::{
self, AdtDef, Binder, FnSig, IntTy, Predicate, PredicateKind, Ty, TyCtxt, TypeFoldable, UintTy, VariantDiscr,
self, AdtDef, Binder, FnSig, IntTy, ParamEnv, Predicate, PredicateKind, Ty, TyCtxt, TypeFoldable, UintTy,
VariantDiscr,
};
use rustc_span::symbol::Ident;
use rustc_span::{sym, Span, Symbol, DUMMY_SP};
@ -151,18 +152,29 @@ pub fn implements_trait<'tcx>(
ty: Ty<'tcx>,
trait_id: DefId,
ty_params: &[GenericArg<'tcx>],
) -> bool {
implements_trait_with_env(cx.tcx, cx.param_env, ty, trait_id, ty_params)
}
/// Same as `implements_trait` but allows using a `ParamEnv` different from the lint context.
pub fn implements_trait_with_env<'tcx>(
tcx: TyCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
ty: Ty<'tcx>,
trait_id: DefId,
ty_params: &[GenericArg<'tcx>],
) -> bool {
// Clippy shouldn't have infer types
assert!(!ty.needs_infer());
let ty = cx.tcx.erase_regions(ty);
let ty = tcx.erase_regions(ty);
if ty.has_escaping_bound_vars() {
return false;
}
let ty_params = cx.tcx.mk_substs(ty_params.iter());
cx.tcx.infer_ctxt().enter(|infcx| {
let ty_params = tcx.mk_substs(ty_params.iter());
tcx.infer_ctxt().enter(|infcx| {
infcx
.type_implements_trait(trait_id, ty, ty_params, cx.param_env)
.type_implements_trait(trait_id, ty, ty_params, param_env)
.must_apply_modulo_regions()
})
}

View file

@ -95,4 +95,10 @@ enum EnumNotEq {
#[derive(Debug, PartialEq, Eq, Clone)]
struct RustFixWithOtherDerives;
#[derive(PartialEq)]
struct Generic<T>(T);
#[derive(PartialEq, Eq)]
struct GenericPhantom<T>(core::marker::PhantomData<T>);
fn main() {}

View file

@ -95,4 +95,10 @@ enum EnumNotEq {
#[derive(Debug, PartialEq, Clone)]
struct RustFixWithOtherDerives;
#[derive(PartialEq)]
struct Generic<T>(T);
#[derive(PartialEq, Eq)]
struct GenericPhantom<T>(core::marker::PhantomData<T>);
fn main() {}