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[WIP] some mir typeck cleanup #95763

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[WIP] some mir typeck cleanup #95763

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3518a5c
small mir typeck cleanup
lcnr Apr 7, 2022
f7638f2
move `type_check_internal` into `type_check`
lcnr Apr 7, 2022
1b77f62
`TypeVerifier`: remove `error_reported`
lcnr Apr 7, 2022
855e024
`const_evaluatable_unchecked`: always point to the const
lcnr Apr 7, 2022
c076be2
require all locals to be well formed when used in a place
lcnr Apr 7, 2022
38b5a0a
require that all constants are wf
lcnr Apr 7, 2022
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7 changes: 4 additions & 3 deletions compiler/rustc_borrowck/src/type_check/canonical.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -89,12 +89,13 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
locations: Locations,
category: ConstraintCategory,
) {
self.prove_predicates(
Some(ty::Binder::dummy(ty::PredicateKind::Trait(ty::TraitPredicate {
self.prove_predicate(
ty::Binder::dummy(ty::PredicateKind::Trait(ty::TraitPredicate {
trait_ref,
constness: ty::BoundConstness::NotConst,
polarity: ty::ImplPolarity::Positive,
}))),
}))
.to_predicate(self.tcx()),
locations,
category,
);
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_borrowck/src/type_check/free_region_relations.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -280,7 +280,7 @@ impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> {
// }
// impl Foo for () {
// type Bar = ();
// fn foo(&self) ->&() {}
// fn foo(&self) -> &() {}
// }
// ```
// Both &Self::Bar and &() are WF
Expand Down
231 changes: 88 additions & 143 deletions compiler/rustc_borrowck/src/type_check/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -90,7 +90,7 @@ macro_rules! span_mirbug_and_err {
($context:expr, $elem:expr, $($message:tt)*) => ({
{
span_mirbug!($context, $elem, $($message)*);
$context.error()
$context.tcx().ty_error()
}
})
}
Expand Down Expand Up @@ -181,107 +181,69 @@ pub(crate) fn type_check<'mir, 'tcx>(
upvars,
};

let opaque_type_values = type_check_internal(
let mut checker = TypeChecker::new(
infcx,
param_env,
body,
promoted,
param_env,
&region_bound_pairs,
implicit_region_bound,
&mut borrowck_context,
|mut cx| {
cx.equate_inputs_and_outputs(&body, universal_regions, &normalized_inputs_and_output);
liveness::generate(
&mut cx,
body,
elements,
flow_inits,
move_data,
location_table,
use_polonius,
);

translate_outlives_facts(&mut cx);
let opaque_type_values =
infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types();

opaque_type_values
.into_iter()
.map(|(opaque_type_key, decl)| {
cx.fully_perform_op(
Locations::All(body.span),
ConstraintCategory::OpaqueType,
CustomTypeOp::new(
|infcx| {
infcx.register_member_constraints(
param_env,
opaque_type_key,
decl.hidden_type.ty,
decl.hidden_type.span,
);
Ok(InferOk { value: (), obligations: vec![] })
},
|| "opaque_type_map".to_string(),
),
)
.unwrap();
let mut hidden_type = infcx.resolve_vars_if_possible(decl.hidden_type);
trace!(
"finalized opaque type {:?} to {:#?}",
opaque_type_key,
hidden_type.ty.kind()
);
if hidden_type.has_infer_types_or_consts() {
infcx.tcx.sess.delay_span_bug(
decl.hidden_type.span,
&format!("could not resolve {:#?}", hidden_type.ty.kind()),
);
hidden_type.ty = infcx.tcx.ty_error();
}

(opaque_type_key, (hidden_type, decl.origin))
})
.collect()
},
);

MirTypeckResults { constraints, universal_region_relations, opaque_type_values }
}
let mut verifier = TypeVerifier::new(&mut checker, promoted);
verifier.visit_body(&body);

#[instrument(
skip(infcx, body, promoted, region_bound_pairs, borrowck_context, extra),
level = "debug"
)]
fn type_check_internal<'a, 'tcx, R>(
infcx: &'a InferCtxt<'a, 'tcx>,
param_env: ty::ParamEnv<'tcx>,
body: &'a Body<'tcx>,
promoted: &'a IndexVec<Promoted, Body<'tcx>>,
region_bound_pairs: &'a RegionBoundPairs<'tcx>,
implicit_region_bound: ty::Region<'tcx>,
borrowck_context: &'a mut BorrowCheckContext<'a, 'tcx>,
extra: impl FnOnce(TypeChecker<'a, 'tcx>) -> R,
) -> R {
let mut checker = TypeChecker::new(
infcx,
checker.typeck_mir(body);

checker.equate_inputs_and_outputs(&body, universal_regions, &normalized_inputs_and_output);
liveness::generate(
&mut checker,
body,
param_env,
region_bound_pairs,
implicit_region_bound,
borrowck_context,
elements,
flow_inits,
move_data,
location_table,
use_polonius,
);
let errors_reported = {
let mut verifier = TypeVerifier::new(&mut checker, promoted);
verifier.visit_body(&body);
verifier.errors_reported
};

if !errors_reported {
// if verifier failed, don't do further checks to avoid ICEs
checker.typeck_mir(body);
}
translate_outlives_facts(&mut checker);
let opaque_type_values = infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types();
let opaque_type_values = opaque_type_values
.into_iter()
.map(|(opaque_type_key, decl)| {
checker
.fully_perform_op(
Locations::All(body.span),
ConstraintCategory::OpaqueType,
CustomTypeOp::new(
|infcx| {
infcx.register_member_constraints(
param_env,
opaque_type_key,
decl.hidden_type.ty,
decl.hidden_type.span,
);
Ok(InferOk { value: (), obligations: vec![] })
},
|| "opaque_type_map".to_string(),
),
)
.unwrap();
let mut hidden_type = infcx.resolve_vars_if_possible(decl.hidden_type);
trace!("finalized opaque type {:?} to {:#?}", opaque_type_key, hidden_type.ty.kind());
if hidden_type.has_infer_types_or_consts() {
infcx.tcx.sess.delay_span_bug(
decl.hidden_type.span,
&format!("could not resolve {:#?}", hidden_type.ty.kind()),
);
hidden_type.ty = infcx.tcx.ty_error();
}

extra(checker)
(opaque_type_key, (hidden_type, decl.origin))
})
.collect();

MirTypeckResults { constraints, universal_region_relations, opaque_type_values }
}

fn translate_outlives_facts(typeck: &mut TypeChecker<'_, '_>) {
Expand Down Expand Up @@ -323,14 +285,11 @@ enum FieldAccessError {

/// Verifies that MIR types are sane to not crash further checks.
///
/// The sanitize_XYZ methods here take an MIR object and compute its
/// type, calling `span_mirbug` and returning an error type if there
/// is a problem.
/// FIXME: Merge this with `TypeChecker`.
struct TypeVerifier<'a, 'b, 'tcx> {
cx: &'a mut TypeChecker<'b, 'tcx>,
promoted: &'b IndexVec<Promoted, Body<'tcx>>,
last_span: Span,
errors_reported: bool,
}

impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
Expand Down Expand Up @@ -387,34 +346,25 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
};
if let Some(uv) = maybe_uneval {
if let Some(promoted) = uv.promoted {
let check_err = |verifier: &mut TypeVerifier<'a, 'b, 'tcx>,
promoted: &Body<'tcx>,
ty,
san_ty| {
if let Err(terr) = verifier.cx.eq_types(
let promoted_body = &self.promoted[promoted];
self.sanitize_promoted(promoted_body, location);

let promoted_ty = promoted_body.return_ty();
if let Err(terr) = self.cx.eq_types(
ty,
promoted_ty,
location.to_locations(),
ConstraintCategory::Boring,
) {
span_mirbug!(
self,
promoted_body,
"bad promoted type ({:?}: {:?}): {:?}",
ty,
san_ty,
location.to_locations(),
ConstraintCategory::Boring,
) {
span_mirbug!(
verifier,
promoted,
"bad promoted type ({:?}: {:?}): {:?}",
ty,
san_ty,
terr
);
};
promoted_ty,
terr
);
};

if !self.errors_reported {
let promoted_body = &self.promoted[promoted];
self.sanitize_promoted(promoted_body, location);

let promoted_ty = promoted_body.return_ty();
check_err(self, promoted_body, ty, promoted_ty);
}
} else {
if let Err(terr) = self.cx.fully_perform_op(
location.to_locations(),
Expand Down Expand Up @@ -450,14 +400,12 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
}
}

if let ty::FnDef(def_id, substs) = *constant.literal.ty().kind() {
let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs);
self.cx.normalize_and_prove_instantiated_predicates(
def_id,
instantiated_predicates,
location.to_locations(),
);
}
self.cx.prove_predicate(
ty::Binder::dummy(ty::PredicateKind::WellFormed(constant.literal.ty().into()))
.to_predicate(self.tcx()),
location.to_locations(),
ConstraintCategory::Boring,
);
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didn't we file a bug about this?

}
}

Expand Down Expand Up @@ -512,9 +460,6 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
for local_decl in &body.local_decls {
self.sanitize_type(local_decl, local_decl.ty);
}
if self.errors_reported {
return;
}
self.super_body(body);
}
}
Expand All @@ -524,7 +469,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
cx: &'a mut TypeChecker<'b, 'tcx>,
promoted: &'b IndexVec<Promoted, Body<'tcx>>,
) -> Self {
TypeVerifier { promoted, last_span: cx.body.span, cx, errors_reported: false }
TypeVerifier { promoted, last_span: cx.body.span, cx }
}

fn body(&self) -> &Body<'tcx> {
Expand Down Expand Up @@ -558,13 +503,21 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
for elem in place.projection.iter() {
if place_ty.variant_index.is_none() {
if place_ty.ty.references_error() {
assert!(self.errors_reported);
return PlaceTy::from_ty(self.tcx().ty_error());
}
}
place_ty = self.sanitize_projection(place_ty, elem, place, location);
}

self.cx.prove_predicate(
ty::Binder::dummy(ty::PredicateKind::WellFormed(
self.body().local_decls[place.local].ty.into(),
))
.to_predicate(self.tcx()),
location.to_locations(),
ConstraintCategory::Boring,
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do we have a known bug that is affected by this?

);

if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context {
let tcx = self.tcx();
let trait_ref = ty::TraitRef {
Expand Down Expand Up @@ -629,10 +582,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {

self.visit_body(&promoted_body);

if !self.errors_reported {
// if verifier failed, don't do further checks to avoid ICEs
self.cx.typeck_mir(promoted_body);
}
self.cx.typeck_mir(promoted_body);

self.cx.body = parent_body;
// Merge the outlives constraints back in, at the given location.
Expand Down Expand Up @@ -790,11 +740,6 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
}
}

fn error(&mut self) -> Ty<'tcx> {
self.errors_reported = true;
self.tcx().ty_error()
}

fn field_ty(
&mut self,
parent: &dyn fmt::Debug,
Expand Down Expand Up @@ -1926,7 +1871,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
}
}

&Rvalue::NullaryOp(_, ty) => {
&Rvalue::NullaryOp(NullOp::SizeOf | NullOp::AlignOf, ty) => {
let trait_ref = ty::TraitRef {
def_id: tcx.require_lang_item(LangItem::Sized, Some(self.last_span)),
substs: tcx.mk_substs_trait(ty, &[]),
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -113,7 +113,7 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
infcx.tcx.struct_span_lint_hir(
lint::builtin::CONST_EVALUATABLE_UNCHECKED,
infcx.tcx.hir().local_def_id_to_hir_id(local_def_id),
span,
tcx.def_span(local_def_id),
|err| {
err.build("cannot use constants which depend on generic parameters in types")
.emit();
Expand Down
4 changes: 2 additions & 2 deletions library/std/src/collections/hash/map.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2878,8 +2878,8 @@ where
#[stable(feature = "hash_extend_copy", since = "1.4.0")]
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for HashMap<K, V, S>
where
K: Eq + Hash + Copy,
V: Copy,
K: Eq + Hash + Copy + 'a,
V: Copy + 'a,
S: BuildHasher,
{
#[inline]
Expand Down
2 changes: 2 additions & 0 deletions src/test/ui/borrowck/issue-7573.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,8 @@ pub fn remove_package_from_database() {
lines_to_use.push(installed_id);
//~^ ERROR borrowed data escapes outside of closure
//~| NOTE `installed_id` escapes the closure body here
//~| NOTE requirement occurs because of a mutable reference to `Vec<&CrateId>`
//~| NOTE mutable references are invariant over their type parameter
};
list_database(push_id);

Expand Down
4 changes: 4 additions & 0 deletions src/test/ui/borrowck/issue-7573.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,10 @@ LL | let push_id = |installed_id: &CrateId| {
LL |
LL | lines_to_use.push(installed_id);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `installed_id` escapes the closure body here
|
= note: requirement occurs because of a mutable reference to `Vec<&CrateId>`
= note: mutable references are invariant over their type parameter
= help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance

error: aborting due to previous error

Expand Down
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