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Pre-populate MIR with opaques, prefer subst-relate candidate

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This commit is contained in:
Michael Goulet 2023-05-18 19:05:43 +00:00
parent e3f8beaed6
commit a2d806d56d
3 changed files with 86 additions and 27 deletions
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62
compiler/rustc_borrowck/src/type_check/mod.rs
View File

@ -26,6 +26,7 @@ use rustc_middle::mir::tcx::PlaceTy;
use rustc_middle::mir::visit::{NonMutatingUseContext, PlaceContext, Visitor};
use rustc_middle::mir::AssertKind;
use rustc_middle::mir::*;
use rustc_middle::traits::ObligationCause;
use rustc_middle::ty::adjustment::PointerCast;
use rustc_middle::ty::cast::CastTy;
use rustc_middle::ty::subst::{SubstsRef, UserSubsts};
@ -48,6 +49,7 @@ use rustc_mir_dataflow::impls::MaybeInitializedPlaces;
use rustc_mir_dataflow::move_paths::MoveData;
use rustc_mir_dataflow::ResultsCursor;
use crate::renumber::RegionCtxt;
use crate::session_diagnostics::MoveUnsized;
use crate::{
borrow_set::BorrowSet,
@ -183,6 +185,15 @@ pub(crate) fn type_check<'mir, 'tcx>(
&mut borrowck_context,
);
// FIXME(-Ztrait-solver=next): A bit dubious that we're only registering
// predefined opaques in the typeck root.
// FIXME(-Ztrait-solver=next): This is also totally wrong for TAITs, since
// the HIR typeck map defining usages back to their definition params,
// they won't actually match up with the usages in this body...
if infcx.tcx.trait_solver_next() && !infcx.tcx.is_typeck_child(body.source.def_id()) {
checker.register_predefined_opaques_in_new_solver();
}
let mut verifier = TypeVerifier::new(&mut checker, promoted);
verifier.visit_body(&body);
@ -1023,6 +1034,57 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
checker
}
pub(super) fn register_predefined_opaques_in_new_solver(&mut self) {
// OK to use the identity substitutions for each opaque type key, since
// we remap opaques from HIR typeck back to their definition params.
let opaques: Vec<_> = self
.infcx
.tcx
.typeck(self.body.source.def_id().expect_local())
.concrete_opaque_types
.iter()
.map(|(&def_id, &hidden_ty)| {
let substs = ty::InternalSubsts::identity_for_item(self.infcx.tcx, def_id);
(ty::OpaqueTypeKey { def_id, substs }, hidden_ty)
})
.collect();
let renumbered_opaques = self.infcx.tcx.fold_regions(opaques, |_, _| {
self.infcx.next_nll_region_var(
NllRegionVariableOrigin::Existential { from_forall: false },
|| RegionCtxt::Unknown,
)
});
let param_env = self.param_env;
let result = self.fully_perform_op(
Locations::All(self.body.span),
ConstraintCategory::OpaqueType,
CustomTypeOp::new(
|ocx| {
for (key, hidden_ty) in renumbered_opaques {
ocx.register_infer_ok_obligations(
ocx.infcx.register_hidden_type_in_new_solver(
key,
param_env,
hidden_ty.ty,
)?,
);
}
Ok(())
},
"register pre-defined opaques",
),
);
if result.is_err() {
self.infcx.tcx.sess.delay_span_bug(
self.body.span,
"failed re-defining predefined opaques in mir typeck",
);
}
}
fn body(&self) -> &Body<'tcx> {
self.body
}

42
compiler/rustc_trait_selection/src/solve/mod.rs
View File

@ -239,34 +239,34 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
evaluate_normalizes_to(self, alias_rhs, lhs, direction, Invert::Yes).ok(),
);
// Relate via substs
candidates.extend(
self.probe(|ecx| {
let span = tracing::span!(
tracing::Level::DEBUG,
"compute_alias_relate_goal(relate_via_substs)",
?alias_lhs,
?alias_rhs,
?direction
);
let _enter = span.enter();
let subst_relate_response = self.probe(|ecx| {
let span = tracing::span!(
tracing::Level::DEBUG,
"compute_alias_relate_goal(relate_via_substs)",
?alias_lhs,
?alias_rhs,
?direction
);
let _enter = span.enter();
match direction {
ty::AliasRelationDirection::Equate => {
ecx.eq(goal.param_env, alias_lhs, alias_rhs)?;
}
ty::AliasRelationDirection::Subtype => {
ecx.sub(goal.param_env, alias_lhs, alias_rhs)?;
}
match direction {
ty::AliasRelationDirection::Equate => {
ecx.eq(goal.param_env, alias_lhs, alias_rhs)?;
}
ty::AliasRelationDirection::Subtype => {
ecx.sub(goal.param_env, alias_lhs, alias_rhs)?;
}
}
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
})
.ok(),
);
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
});
candidates.extend(subst_relate_response);
debug!(?candidates);
if let Some(merged) = self.try_merge_responses(&candidates) {
Ok(merged)
} else if let Ok(subst_relate_response) = subst_relate_response {
Ok(subst_relate_response)
} else {
self.flounder(&candidates)
}

9
compiler/rustc_trait_selection/src/solve/opaques.rs
View File

@ -1,6 +1,6 @@
use rustc_middle::traits::query::NoSolution;
use rustc_middle::traits::solve::{Certainty, Goal, QueryResult};
use rustc_middle::traits::{ObligationCause, Reveal};
use rustc_middle::traits::Reveal;
use rustc_middle::ty;
use rustc_middle::ty::util::NotUniqueParam;
@ -37,11 +37,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
Ok(()) => {}
}
// Prefer opaques registered already.
let matches = self.unify_existing_opaque_tys(
goal.param_env,
opaque_ty,
expected
);
let matches =
self.unify_existing_opaque_tys(goal.param_env, opaque_ty, expected);
if !matches.is_empty() {
if let Some(response) = self.try_merge_responses(&matches) {
return Ok(response);