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Auto merge of #121018 - oli-obk:impl_unsafety, r=TaKO8Ki

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Fully stop using the HIR in trait impl checks

At least I hope I found all happy path usages. I'll need to check if I can figure out a way to make queries declare that they don't access the HIR except in error paths
This commit is contained in:
bors 2024-02-14 07:27:11 +00:00
commit bb89df6903
5 changed files with 80 additions and 69 deletions
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78
compiler/rustc_hir_analysis/src/coherence/builtin.rs
View File

@ -15,7 +15,7 @@ use rustc_infer::infer::{DefineOpaqueTypes, TyCtxtInferExt};
use rustc_infer::traits::Obligation;
use rustc_middle::ty::adjustment::CoerceUnsizedInfo;
use rustc_middle::ty::{self, suggest_constraining_type_params, Ty, TyCtxt, TypeVisitableExt};
use rustc_span::Span;
use rustc_span::{Span, DUMMY_SP};
use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt;
use rustc_trait_selection::traits::misc::{
type_allowed_to_implement_const_param_ty, type_allowed_to_implement_copy,
@ -25,13 +25,14 @@ use rustc_trait_selection::traits::ObligationCtxt;
use rustc_trait_selection::traits::{self, ObligationCause};
use std::collections::BTreeMap;
pub fn check_trait(
tcx: TyCtxt<'_>,
pub fn check_trait<'tcx>(
tcx: TyCtxt<'tcx>,
trait_def_id: DefId,
impl_def_id: LocalDefId,
impl_header: ty::ImplTraitHeader<'tcx>,
) -> Result<(), ErrorGuaranteed> {
let lang_items = tcx.lang_items();
let checker = Checker { tcx, trait_def_id, impl_def_id };
let checker = Checker { tcx, trait_def_id, impl_def_id, impl_header };
let mut res = checker.check(lang_items.drop_trait(), visit_implementation_of_drop);
res = res.and(checker.check(lang_items.copy_trait(), visit_implementation_of_copy));
res = res.and(
@ -50,24 +51,25 @@ struct Checker<'tcx> {
tcx: TyCtxt<'tcx>,
trait_def_id: DefId,
impl_def_id: LocalDefId,
impl_header: ty::ImplTraitHeader<'tcx>,
}
impl<'tcx> Checker<'tcx> {
fn check(
&self,
trait_def_id: Option<DefId>,
f: impl FnOnce(TyCtxt<'tcx>, LocalDefId) -> Result<(), ErrorGuaranteed>,
f: impl FnOnce(&Self) -> Result<(), ErrorGuaranteed>,
) -> Result<(), ErrorGuaranteed> {
if Some(self.trait_def_id) == trait_def_id { f(self.tcx, self.impl_def_id) } else { Ok(()) }
if Some(self.trait_def_id) == trait_def_id { f(self) } else { Ok(()) }
}
}
fn visit_implementation_of_drop(
tcx: TyCtxt<'_>,
impl_did: LocalDefId,
) -> Result<(), ErrorGuaranteed> {
fn visit_implementation_of_drop(checker: &Checker<'_>) -> Result<(), ErrorGuaranteed> {
let tcx = checker.tcx;
let header = checker.impl_header;
let impl_did = checker.impl_def_id;
// Destructors only work on local ADT types.
match tcx.type_of(impl_did).instantiate_identity().kind() {
match header.trait_ref.self_ty().kind() {
ty::Adt(def, _) if def.did().is_local() => return Ok(()),
ty::Error(_) => return Ok(()),
_ => {}
@ -78,13 +80,13 @@ fn visit_implementation_of_drop(
Err(tcx.dcx().emit_err(errors::DropImplOnWrongItem { span: impl_.self_ty.span }))
}
fn visit_implementation_of_copy(
tcx: TyCtxt<'_>,
impl_did: LocalDefId,
) -> Result<(), ErrorGuaranteed> {
fn visit_implementation_of_copy(checker: &Checker<'_>) -> Result<(), ErrorGuaranteed> {
let tcx = checker.tcx;
let impl_header = checker.impl_header;
let impl_did = checker.impl_def_id;
debug!("visit_implementation_of_copy: impl_did={:?}", impl_did);
let self_type = tcx.type_of(impl_did).instantiate_identity();
let self_type = impl_header.trait_ref.self_ty();
debug!("visit_implementation_of_copy: self_type={:?} (bound)", self_type);
let param_env = tcx.param_env(impl_did);
@ -92,56 +94,58 @@ fn visit_implementation_of_copy(
debug!("visit_implementation_of_copy: self_type={:?} (free)", self_type);
if let ty::ImplPolarity::Negative = tcx.impl_polarity(impl_did) {
if let ty::ImplPolarity::Negative = impl_header.polarity {
return Ok(());
}
let span = tcx.hir().expect_item(impl_did).expect_impl().self_ty.span;
let cause = traits::ObligationCause::misc(span, impl_did);
let cause = traits::ObligationCause::misc(DUMMY_SP, impl_did);
match type_allowed_to_implement_copy(tcx, param_env, self_type, cause) {
Ok(()) => Ok(()),
Err(CopyImplementationError::InfringingFields(fields)) => {
let span = tcx.hir().expect_item(impl_did).expect_impl().self_ty.span;
Err(infringing_fields_error(tcx, fields, LangItem::Copy, impl_did, span))
}
Err(CopyImplementationError::NotAnAdt) => {
let span = tcx.hir().expect_item(impl_did).expect_impl().self_ty.span;
Err(tcx.dcx().emit_err(errors::CopyImplOnNonAdt { span }))
}
Err(CopyImplementationError::HasDestructor) => {
let span = tcx.hir().expect_item(impl_did).expect_impl().self_ty.span;
Err(tcx.dcx().emit_err(errors::CopyImplOnTypeWithDtor { span }))
}
}
}
fn visit_implementation_of_const_param_ty(
tcx: TyCtxt<'_>,
impl_did: LocalDefId,
) -> Result<(), ErrorGuaranteed> {
let self_type = tcx.type_of(impl_did).instantiate_identity();
fn visit_implementation_of_const_param_ty(checker: &Checker<'_>) -> Result<(), ErrorGuaranteed> {
let tcx = checker.tcx;
let header = checker.impl_header;
let impl_did = checker.impl_def_id;
let self_type = header.trait_ref.self_ty();
assert!(!self_type.has_escaping_bound_vars());
let param_env = tcx.param_env(impl_did);
if let ty::ImplPolarity::Negative = tcx.impl_polarity(impl_did) {
if let ty::ImplPolarity::Negative = header.polarity {
return Ok(());
}
let span = tcx.hir().expect_item(impl_did).expect_impl().self_ty.span;
let cause = traits::ObligationCause::misc(span, impl_did);
let cause = traits::ObligationCause::misc(DUMMY_SP, impl_did);
match type_allowed_to_implement_const_param_ty(tcx, param_env, self_type, cause) {
Ok(()) => Ok(()),
Err(ConstParamTyImplementationError::InfrigingFields(fields)) => {
let span = tcx.hir().expect_item(impl_did).expect_impl().self_ty.span;
Err(infringing_fields_error(tcx, fields, LangItem::ConstParamTy, impl_did, span))
}
Err(ConstParamTyImplementationError::NotAnAdtOrBuiltinAllowed) => {
let span = tcx.hir().expect_item(impl_did).expect_impl().self_ty.span;
Err(tcx.dcx().emit_err(errors::ConstParamTyImplOnNonAdt { span }))
}
}
}
fn visit_implementation_of_coerce_unsized(
tcx: TyCtxt<'_>,
impl_did: LocalDefId,
) -> Result<(), ErrorGuaranteed> {
fn visit_implementation_of_coerce_unsized(checker: &Checker<'_>) -> Result<(), ErrorGuaranteed> {
let tcx = checker.tcx;
let impl_did = checker.impl_def_id;
debug!("visit_implementation_of_coerce_unsized: impl_did={:?}", impl_did);
// Just compute this for the side-effects, in particular reporting
@ -151,20 +155,20 @@ fn visit_implementation_of_coerce_unsized(
tcx.at(span).ensure().coerce_unsized_info(impl_did)
}
fn visit_implementation_of_dispatch_from_dyn(
tcx: TyCtxt<'_>,
impl_did: LocalDefId,
) -> Result<(), ErrorGuaranteed> {
fn visit_implementation_of_dispatch_from_dyn(checker: &Checker<'_>) -> Result<(), ErrorGuaranteed> {
let tcx = checker.tcx;
let header = checker.impl_header;
let impl_did = checker.impl_def_id;
let trait_ref = header.trait_ref;
debug!("visit_implementation_of_dispatch_from_dyn: impl_did={:?}", impl_did);
let span = tcx.def_span(impl_did);
let dispatch_from_dyn_trait = tcx.require_lang_item(LangItem::DispatchFromDyn, Some(span));
let source = tcx.type_of(impl_did).instantiate_identity();
let source = trait_ref.self_ty();
assert!(!source.has_escaping_bound_vars());
let target = {
let trait_ref = tcx.impl_trait_ref(impl_did).unwrap().instantiate_identity();
assert_eq!(trait_ref.def_id, dispatch_from_dyn_trait);
trait_ref.args.type_at(1)

25
compiler/rustc_hir_analysis/src/coherence/mod.rs
View File

@ -23,6 +23,7 @@ fn check_impl(
tcx: TyCtxt<'_>,
impl_def_id: LocalDefId,
trait_ref: ty::TraitRef<'_>,
trait_def: &ty::TraitDef,
) -> Result<(), ErrorGuaranteed> {
debug!(
"(checking implementation) adding impl for trait '{:?}', item '{}'",
@ -36,19 +37,20 @@ fn check_impl(
return Ok(());
}
enforce_trait_manually_implementable(tcx, impl_def_id, trait_ref.def_id)
.and(enforce_empty_impls_for_marker_traits(tcx, impl_def_id, trait_ref.def_id))
enforce_trait_manually_implementable(tcx, impl_def_id, trait_ref.def_id, trait_def)
.and(enforce_empty_impls_for_marker_traits(tcx, impl_def_id, trait_ref.def_id, trait_def))
}
fn enforce_trait_manually_implementable(
tcx: TyCtxt<'_>,
impl_def_id: LocalDefId,
trait_def_id: DefId,
trait_def: &ty::TraitDef,
) -> Result<(), ErrorGuaranteed> {
let impl_header_span = tcx.def_span(impl_def_id);
// Disallow *all* explicit impls of traits marked `#[rustc_deny_explicit_impl]`
if tcx.trait_def(trait_def_id).deny_explicit_impl {
if trait_def.deny_explicit_impl {
let trait_name = tcx.item_name(trait_def_id);
let mut err = struct_span_code_err!(
tcx.dcx(),
@ -67,8 +69,7 @@ fn enforce_trait_manually_implementable(
return Err(err.emit());
}
if let ty::trait_def::TraitSpecializationKind::AlwaysApplicable =
tcx.trait_def(trait_def_id).specialization_kind
if let ty::trait_def::TraitSpecializationKind::AlwaysApplicable = trait_def.specialization_kind
{
if !tcx.features().specialization
&& !tcx.features().min_specialization
@ -87,8 +88,9 @@ fn enforce_empty_impls_for_marker_traits(
tcx: TyCtxt<'_>,
impl_def_id: LocalDefId,
trait_def_id: DefId,
trait_def: &ty::TraitDef,
) -> Result<(), ErrorGuaranteed> {
if !tcx.trait_def(trait_def_id).is_marker {
if !trait_def.is_marker {
return Ok(());
}
@ -132,14 +134,15 @@ fn coherent_trait(tcx: TyCtxt<'_>, def_id: DefId) -> Result<(), ErrorGuaranteed>
let mut res = tcx.ensure().specialization_graph_of(def_id);
for &impl_def_id in impls {
let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().instantiate_identity();
let trait_header = tcx.impl_trait_header(impl_def_id).unwrap().instantiate_identity();
let trait_def = tcx.trait_def(trait_header.trait_ref.def_id);
res = res.and(check_impl(tcx, impl_def_id, trait_ref));
res = res.and(check_object_overlap(tcx, impl_def_id, trait_ref));
res = res.and(check_impl(tcx, impl_def_id, trait_header.trait_ref, trait_def));
res = res.and(check_object_overlap(tcx, impl_def_id, trait_header.trait_ref));
res = res.and(unsafety::check_item(tcx, impl_def_id, trait_ref));
res = res.and(unsafety::check_item(tcx, impl_def_id, trait_header, trait_def));
res = res.and(tcx.ensure().orphan_check_impl(impl_def_id));
res = res.and(builtin::check_trait(tcx, def_id, impl_def_id));
res = res.and(builtin::check_trait(tcx, def_id, impl_def_id, trait_header));
}
res

44
compiler/rustc_hir_analysis/src/coherence/unsafety.rs
View File

@ -2,23 +2,23 @@
//! crate or pertains to a type defined in this crate.
use rustc_errors::{codes::*, struct_span_code_err};
use rustc_hir as hir;
use rustc_hir::Unsafety;
use rustc_middle::ty::{TraitRef, TyCtxt};
use rustc_middle::ty::{ImplPolarity::*, ImplTraitHeader, TraitDef, TyCtxt};
use rustc_span::def_id::LocalDefId;
use rustc_span::ErrorGuaranteed;
pub(super) fn check_item(
tcx: TyCtxt<'_>,
def_id: LocalDefId,
trait_ref: TraitRef<'_>,
trait_header: ImplTraitHeader<'_>,
trait_def: &TraitDef,
) -> Result<(), ErrorGuaranteed> {
let item = tcx.hir().expect_item(def_id);
let impl_ = item.expect_impl();
let trait_def = tcx.trait_def(trait_ref.def_id);
let unsafe_attr = impl_.generics.params.iter().find(|p| p.pure_wrt_drop).map(|_| "may_dangle");
match (trait_def.unsafety, unsafe_attr, impl_.unsafety, impl_.polarity) {
(Unsafety::Normal, None, Unsafety::Unsafe, hir::ImplPolarity::Positive) => {
let trait_ref = trait_header.trait_ref;
let unsafe_attr =
tcx.generics_of(def_id).params.iter().find(|p| p.pure_wrt_drop).map(|_| "may_dangle");
match (trait_def.unsafety, unsafe_attr, trait_header.unsafety, trait_header.polarity) {
(Unsafety::Normal, None, Unsafety::Unsafe, Positive | Reservation) => {
let span = tcx.def_span(def_id);
return Err(struct_span_code_err!(
tcx.dcx(),
tcx.def_span(def_id),
@ -27,7 +27,7 @@ pub(super) fn check_item(
trait_ref.print_trait_sugared()
)
.with_span_suggestion_verbose(
item.span.with_hi(item.span.lo() + rustc_span::BytePos(7)),
span.with_hi(span.lo() + rustc_span::BytePos(7)),
"remove `unsafe` from this trait implementation",
"",
rustc_errors::Applicability::MachineApplicable,
@ -35,10 +35,11 @@ pub(super) fn check_item(
.emit());
}
(Unsafety::Unsafe, _, Unsafety::Normal, hir::ImplPolarity::Positive) => {
(Unsafety::Unsafe, _, Unsafety::Normal, Positive | Reservation) => {
let span = tcx.def_span(def_id);
return Err(struct_span_code_err!(
tcx.dcx(),
tcx.def_span(def_id),
span,
E0200,
"the trait `{}` requires an `unsafe impl` declaration",
trait_ref.print_trait_sugared()
@ -50,7 +51,7 @@ pub(super) fn check_item(
trait_ref.print_trait_sugared()
))
.with_span_suggestion_verbose(
item.span.shrink_to_lo(),
span.shrink_to_lo(),
"add `unsafe` to this trait implementation",
"unsafe ",
rustc_errors::Applicability::MaybeIncorrect,
@ -58,10 +59,11 @@ pub(super) fn check_item(
.emit());
}
(Unsafety::Normal, Some(attr_name), Unsafety::Normal, hir::ImplPolarity::Positive) => {
(Unsafety::Normal, Some(attr_name), Unsafety::Normal, Positive | Reservation) => {
let span = tcx.def_span(def_id);
return Err(struct_span_code_err!(
tcx.dcx(),
tcx.def_span(def_id),
span,
E0569,
"requires an `unsafe impl` declaration due to `#[{}]` attribute",
attr_name
@ -73,7 +75,7 @@ pub(super) fn check_item(
trait_ref.print_trait_sugared()
))
.with_span_suggestion_verbose(
item.span.shrink_to_lo(),
span.shrink_to_lo(),
"add `unsafe` to this trait implementation",
"unsafe ",
rustc_errors::Applicability::MaybeIncorrect,
@ -81,14 +83,14 @@ pub(super) fn check_item(
.emit());
}
(_, _, Unsafety::Unsafe, hir::ImplPolarity::Negative(_)) => {
(_, _, Unsafety::Unsafe, Negative) => {
// Reported in AST validation
tcx.dcx().span_delayed_bug(item.span, "unsafe negative impl");
tcx.dcx().span_delayed_bug(tcx.def_span(def_id), "unsafe negative impl");
Ok(())
}
(_, _, Unsafety::Normal, hir::ImplPolarity::Negative(_))
| (Unsafety::Unsafe, _, Unsafety::Unsafe, hir::ImplPolarity::Positive)
| (Unsafety::Normal, Some(_), Unsafety::Unsafe, hir::ImplPolarity::Positive)
(_, _, Unsafety::Normal, Negative)
| (Unsafety::Unsafe, _, Unsafety::Unsafe, Positive | Reservation)
| (Unsafety::Normal, Some(_), Unsafety::Unsafe, Positive | Reservation)
| (Unsafety::Normal, None, Unsafety::Normal, _) => Ok(()),
}
}

1
compiler/rustc_hir_analysis/src/collect.rs
View File

@ -1539,6 +1539,7 @@ fn impl_trait_header(
};
ty::EarlyBinder::bind(ty::ImplTraitHeader {
trait_ref,
unsafety: impl_.unsafety,
polarity: polarity_of_impl(tcx, def_id, impl_, item.span)
})
})

1
compiler/rustc_middle/src/ty/mod.rs
View File

@ -252,6 +252,7 @@ pub struct ImplHeader<'tcx> {
pub struct ImplTraitHeader<'tcx> {
pub trait_ref: ty::TraitRef<'tcx>,
pub polarity: ImplPolarity,
pub unsafety: hir::Unsafety,
}
#[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable)]