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@oli-obk
oli-obk committed Jan 12, 2024
1 parent 767d253 commit 796c54a
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Showing 24 changed files with 529 additions and 193 deletions.
156 changes: 91 additions & 65 deletions compiler/rustc_hir_analysis/src/coherence/builtin.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,14 +25,21 @@ use rustc_trait_selection::traits::ObligationCtxt;
use rustc_trait_selection::traits::{self, ObligationCause};
use std::collections::BTreeMap;

pub fn check_trait(tcx: TyCtxt<'_>, trait_def_id: DefId) {
pub fn check_trait(tcx: TyCtxt<'_>, trait_def_id: DefId) -> Result<(), ErrorGuaranteed> {
let lang_items = tcx.lang_items();
Checker { tcx, trait_def_id }
.check(lang_items.drop_trait(), visit_implementation_of_drop)
.check(lang_items.copy_trait(), visit_implementation_of_copy)
.check(lang_items.const_param_ty_trait(), visit_implementation_of_const_param_ty)
.check(lang_items.coerce_unsized_trait(), visit_implementation_of_coerce_unsized)
.check(lang_items.dispatch_from_dyn_trait(), visit_implementation_of_dispatch_from_dyn);
let checker = Checker { tcx, trait_def_id };
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(
checker.check(lang_items.const_param_ty_trait(), visit_implementation_of_const_param_ty),
);
res = res.and(
checker.check(lang_items.coerce_unsized_trait(), visit_implementation_of_coerce_unsized),
);
res.and(
checker
.check(lang_items.dispatch_from_dyn_trait(), visit_implementation_of_dispatch_from_dyn),
)
}

struct Checker<'tcx> {
Expand All @@ -41,33 +48,40 @@ struct Checker<'tcx> {
}

impl<'tcx> Checker<'tcx> {
fn check<F>(&self, trait_def_id: Option<DefId>, mut f: F) -> &Self
fn check<F>(&self, trait_def_id: Option<DefId>, mut f: F) -> Result<(), ErrorGuaranteed>
where
F: FnMut(TyCtxt<'tcx>, LocalDefId),
F: FnMut(TyCtxt<'tcx>, LocalDefId) -> Result<(), ErrorGuaranteed>,
{
let mut res = Ok(());
if Some(self.trait_def_id) == trait_def_id {
for &impl_def_id in self.tcx.hir().trait_impls(self.trait_def_id) {
f(self.tcx, impl_def_id);
res = res.and(f(self.tcx, impl_def_id));
}
}
self
res
}
}

fn visit_implementation_of_drop(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
fn visit_implementation_of_drop(
tcx: TyCtxt<'_>,
impl_did: LocalDefId,
) -> Result<(), ErrorGuaranteed> {
// Destructors only work on local ADT types.
match tcx.type_of(impl_did).instantiate_identity().kind() {
ty::Adt(def, _) if def.did().is_local() => return,
ty::Error(_) => return,
ty::Adt(def, _) if def.did().is_local() => return Ok(()),
ty::Error(_) => return Ok(()),
_ => {}
}

let impl_ = tcx.hir().expect_item(impl_did).expect_impl();

tcx.dcx().emit_err(errors::DropImplOnWrongItem { span: impl_.self_ty.span });
Err(tcx.dcx().emit_err(errors::DropImplOnWrongItem { span: impl_.self_ty.span }))
}

fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
fn visit_implementation_of_copy(
tcx: TyCtxt<'_>,
impl_did: LocalDefId,
) -> Result<(), ErrorGuaranteed> {
debug!("visit_implementation_of_copy: impl_did={:?}", impl_did);

let self_type = tcx.type_of(impl_did).instantiate_identity();
Expand All @@ -79,59 +93,68 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
debug!("visit_implementation_of_copy: self_type={:?} (free)", self_type);

let span = match tcx.hir().expect_item(impl_did).expect_impl() {
hir::Impl { polarity: hir::ImplPolarity::Negative(_), .. } => return,
hir::Impl { polarity: hir::ImplPolarity::Negative(_), .. } => return Ok(()),
hir::Impl { self_ty, .. } => self_ty.span,
};

let cause = traits::ObligationCause::misc(span, impl_did);
match type_allowed_to_implement_copy(tcx, param_env, self_type, cause) {
Ok(()) => {}
Ok(()) => Ok(()),
Err(CopyImplementationError::InfringingFields(fields)) => {
infringing_fields_error(tcx, fields, LangItem::Copy, impl_did, span);
Err(infringing_fields_error(tcx, fields, LangItem::Copy, impl_did, span))
}
Err(CopyImplementationError::NotAnAdt) => {
tcx.dcx().emit_err(errors::CopyImplOnNonAdt { span });
Err(tcx.dcx().emit_err(errors::CopyImplOnNonAdt { span }))
}
Err(CopyImplementationError::HasDestructor) => {
tcx.dcx().emit_err(errors::CopyImplOnTypeWithDtor { span });
Err(tcx.dcx().emit_err(errors::CopyImplOnTypeWithDtor { span }))
}
}
}

fn visit_implementation_of_const_param_ty(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
fn visit_implementation_of_const_param_ty(
tcx: TyCtxt<'_>,
impl_did: LocalDefId,
) -> Result<(), ErrorGuaranteed> {
let self_type = tcx.type_of(impl_did).instantiate_identity();
assert!(!self_type.has_escaping_bound_vars());

let param_env = tcx.param_env(impl_did);

let span = match tcx.hir().expect_item(impl_did).expect_impl() {
hir::Impl { polarity: hir::ImplPolarity::Negative(_), .. } => return,
hir::Impl { polarity: hir::ImplPolarity::Negative(_), .. } => return Ok(()),
impl_ => impl_.self_ty.span,
};

let cause = traits::ObligationCause::misc(span, impl_did);
match type_allowed_to_implement_const_param_ty(tcx, param_env, self_type, cause) {
Ok(()) => {}
Ok(()) => Ok(()),
Err(ConstParamTyImplementationError::InfrigingFields(fields)) => {
infringing_fields_error(tcx, fields, LangItem::ConstParamTy, impl_did, span);
Err(infringing_fields_error(tcx, fields, LangItem::ConstParamTy, impl_did, span))
}
Err(ConstParamTyImplementationError::NotAnAdtOrBuiltinAllowed) => {
tcx.dcx().emit_err(errors::ConstParamTyImplOnNonAdt { span });
Err(tcx.dcx().emit_err(errors::ConstParamTyImplOnNonAdt { span }))
}
}
}

fn visit_implementation_of_coerce_unsized(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
fn visit_implementation_of_coerce_unsized(
tcx: TyCtxt<'_>,
impl_did: LocalDefId,
) -> Result<(), ErrorGuaranteed> {
debug!("visit_implementation_of_coerce_unsized: impl_did={:?}", impl_did);

// Just compute this for the side-effects, in particular reporting
// errors; other parts of the code may demand it for the info of
// course.
let span = tcx.def_span(impl_did);
tcx.at(span).coerce_unsized_info(impl_did);
tcx.at(span).ensure().coerce_unsized_info(impl_did)
}

fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
fn visit_implementation_of_dispatch_from_dyn(
tcx: TyCtxt<'_>,
impl_did: LocalDefId,
) -> Result<(), ErrorGuaranteed> {
debug!("visit_implementation_of_dispatch_from_dyn: impl_did={:?}", impl_did);

let span = tcx.def_span(impl_did);
Expand Down Expand Up @@ -166,26 +189,28 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
match (source.kind(), target.kind()) {
(&Ref(r_a, _, mutbl_a), Ref(r_b, _, mutbl_b))
if infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, r_a, *r_b).is_ok()
&& mutbl_a == *mutbl_b => {}
(&RawPtr(tm_a), &RawPtr(tm_b)) if tm_a.mutbl == tm_b.mutbl => (),
&& mutbl_a == *mutbl_b =>
{
Ok(())
}
(&RawPtr(tm_a), &RawPtr(tm_b)) if tm_a.mutbl == tm_b.mutbl => Ok(()),
(&Adt(def_a, args_a), &Adt(def_b, args_b)) if def_a.is_struct() && def_b.is_struct() => {
if def_a != def_b {
let source_path = tcx.def_path_str(def_a.did());
let target_path = tcx.def_path_str(def_b.did());

tcx.dcx().emit_err(errors::DispatchFromDynCoercion {
return Err(tcx.dcx().emit_err(errors::DispatchFromDynCoercion {
span,
trait_name: "DispatchFromDyn",
note: true,
source_path,
target_path,
});

return;
}));
}

let mut res = Ok(());
if def_a.repr().c() || def_a.repr().packed() {
tcx.dcx().emit_err(errors::DispatchFromDynRepr { span });
res = Err(tcx.dcx().emit_err(errors::DispatchFromDynRepr { span }));
}

let fields = &def_a.non_enum_variant().fields;
Expand All @@ -207,11 +232,11 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, ty_a, ty_b)
{
if ok.obligations.is_empty() {
tcx.dcx().emit_err(errors::DispatchFromDynZST {
res = Err(tcx.dcx().emit_err(errors::DispatchFromDynZST {
span,
name: field.name,
ty: ty_a,
});
}));

return false;
}
Expand All @@ -222,13 +247,13 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
.collect::<Vec<_>>();

if coerced_fields.is_empty() {
tcx.dcx().emit_err(errors::DispatchFromDynSingle {
res = Err(tcx.dcx().emit_err(errors::DispatchFromDynSingle {
span,
trait_name: "DispatchFromDyn",
note: true,
});
}));
} else if coerced_fields.len() > 1 {
tcx.dcx().emit_err(errors::DispatchFromDynMulti {
res = Err(tcx.dcx().emit_err(errors::DispatchFromDynMulti {
span,
coercions_note: true,
number: coerced_fields.len(),
Expand All @@ -244,7 +269,7 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
})
.collect::<Vec<_>>()
.join(", "),
});
}));
} else {
let ocx = ObligationCtxt::new(&infcx);
for field in coerced_fields {
Expand All @@ -261,21 +286,25 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
}
let errors = ocx.select_all_or_error();
if !errors.is_empty() {
infcx.err_ctxt().report_fulfillment_errors(errors);
res = Err(infcx.err_ctxt().report_fulfillment_errors(errors));
}

// Finally, resolve all regions.
let outlives_env = OutlivesEnvironment::new(param_env);
let _ = ocx.resolve_regions_and_report_errors(impl_did, &outlives_env);
res = res.and(ocx.resolve_regions_and_report_errors(impl_did, &outlives_env));
}
res
}
_ => {
tcx.dcx().emit_err(errors::CoerceUnsizedMay { span, trait_name: "DispatchFromDyn" });
}
_ => Err(tcx
.dcx()
.emit_err(errors::CoerceUnsizedMay { span, trait_name: "DispatchFromDyn" })),
}
}

pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> CoerceUnsizedInfo {
pub fn coerce_unsized_info<'tcx>(
tcx: TyCtxt<'tcx>,
impl_did: LocalDefId,
) -> Result<CoerceUnsizedInfo, ErrorGuaranteed> {
debug!("compute_coerce_unsized_info(impl_did={:?})", impl_did);
let span = tcx.def_span(impl_did);

Expand All @@ -292,8 +321,6 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
let param_env = tcx.param_env(impl_did);
assert!(!source.has_escaping_bound_vars());

let err_info = CoerceUnsizedInfo { custom_kind: None };

debug!("visit_implementation_of_coerce_unsized: {:?} -> {:?} (free)", source, target);

let infcx = tcx.infer_ctxt().build();
Expand Down Expand Up @@ -337,14 +364,13 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
if def_a != def_b {
let source_path = tcx.def_path_str(def_a.did());
let target_path = tcx.def_path_str(def_b.did());
tcx.dcx().emit_err(errors::DispatchFromDynSame {
return Err(tcx.dcx().emit_err(errors::DispatchFromDynSame {
span,
trait_name: "CoerceUnsized",
note: true,
source_path,
target_path,
});
return err_info;
}));
}

// Here we are considering a case of converting
Expand Down Expand Up @@ -419,12 +445,11 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
.collect::<Vec<_>>();

if diff_fields.is_empty() {
tcx.dcx().emit_err(errors::CoerceUnsizedOneField {
return Err(tcx.dcx().emit_err(errors::CoerceUnsizedOneField {
span,
trait_name: "CoerceUnsized",
note: true,
});
return err_info;
}));
} else if diff_fields.len() > 1 {
let item = tcx.hir().expect_item(impl_did);
let span = if let ItemKind::Impl(hir::Impl { of_trait: Some(t), .. }) = &item.kind {
Expand All @@ -433,7 +458,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
tcx.def_span(impl_did)
};

tcx.dcx().emit_err(errors::CoerceUnsizedMulti {
return Err(tcx.dcx().emit_err(errors::CoerceUnsizedMulti {
span,
coercions_note: true,
number: diff_fields.len(),
Expand All @@ -442,9 +467,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
.map(|&(i, a, b)| format!("`{}` (`{}` to `{}`)", fields[i].name, a, b))
.collect::<Vec<_>>()
.join(", "),
});

return err_info;
}));
}

let (i, a, b) = diff_fields[0];
Expand All @@ -453,8 +476,9 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
}

_ => {
tcx.dcx().emit_err(errors::DispatchFromDynStruct { span, trait_name: "CoerceUnsized" });
return err_info;
return Err(tcx
.dcx()
.emit_err(errors::DispatchFromDynStruct { span, trait_name: "CoerceUnsized" }));
}
};

Expand All @@ -469,15 +493,17 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
);
ocx.register_obligation(obligation);
let errors = ocx.select_all_or_error();
let mut res = Ok(());
if !errors.is_empty() {
infcx.err_ctxt().report_fulfillment_errors(errors);
res = Err(infcx.err_ctxt().report_fulfillment_errors(errors));
}

// Finally, resolve all regions.
let outlives_env = OutlivesEnvironment::new(param_env);
let _ = ocx.resolve_regions_and_report_errors(impl_did, &outlives_env);
ocx.resolve_regions_and_report_errors(impl_did, &outlives_env)?;
res?;

CoerceUnsizedInfo { custom_kind: kind }
Ok(CoerceUnsizedInfo { custom_kind: kind })
}

fn infringing_fields_error(
Expand Down
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