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Re-use TypeChecker instead of passing around some of its fields #89675

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merged 2 commits into from
Oct 12, 2021
Merged

Re-use TypeChecker instead of passing around some of its fields #89675

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597090e
Re-use TypeChecker instead of passing around some of its fields
oli-obk Sep 30, 2021
49b06a2
Directly call relate_types function instead of having a method wrapper
oli-obk Oct 8, 2021
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22 changes: 0 additions & 22 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 @@ -1153,28 +1153,6 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
.convert_all(data);
}

/// Convenient wrapper around `relate_tys::relate_types` -- see
/// that fn for docs.
fn relate_types(
&mut self,
a: Ty<'tcx>,
v: ty::Variance,
b: Ty<'tcx>,
locations: Locations,
category: ConstraintCategory,
) -> Fallible<()> {
relate_tys::relate_types(
self.infcx,
self.param_env,
a,
v,
b,
locations,
category,
self.borrowck_context,
)
}

/// Try to relate `sub <: sup`
fn sub_types(
&mut self,
Expand Down
112 changes: 53 additions & 59 deletions compiler/rustc_borrowck/src/type_check/relate_tys.rs
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Original file line number Diff line number Diff line change
@@ -1,54 +1,44 @@
use rustc_infer::infer::nll_relate::{NormalizationStrategy, TypeRelating, TypeRelatingDelegate};
use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin};
use rustc_infer::infer::NllRegionVariableOrigin;
use rustc_middle::mir::ConstraintCategory;
use rustc_middle::ty::relate::TypeRelation;
use rustc_middle::ty::{self, Const, Ty};
use rustc_trait_selection::traits::query::Fallible;

use crate::constraints::OutlivesConstraint;
use crate::diagnostics::UniverseInfo;
use crate::type_check::{BorrowCheckContext, Locations};

/// Adds sufficient constraints to ensure that `a R b` where `R` depends on `v`:
///
/// - "Covariant" `a <: b`
/// - "Invariant" `a == b`
/// - "Contravariant" `a :> b`
///
/// N.B., the type `a` is permitted to have unresolved inference
/// variables, but not the type `b`.
#[instrument(skip(infcx, param_env, borrowck_context), level = "debug")]
pub(super) fn relate_types<'tcx>(
infcx: &InferCtxt<'_, 'tcx>,
param_env: ty::ParamEnv<'tcx>,
a: Ty<'tcx>,
v: ty::Variance,
b: Ty<'tcx>,
locations: Locations,
category: ConstraintCategory,
borrowck_context: &mut BorrowCheckContext<'_, 'tcx>,
) -> Fallible<()> {
TypeRelating::new(
infcx,
NllTypeRelatingDelegate::new(
infcx,
borrowck_context,
param_env,
locations,
category,
UniverseInfo::relate(a, b),
),
v,
)
.relate(a, b)?;
Ok(())
use crate::type_check::{Locations, TypeChecker};

impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
/// Adds sufficient constraints to ensure that `a R b` where `R` depends on `v`:
///
/// - "Covariant" `a <: b`
/// - "Invariant" `a == b`
/// - "Contravariant" `a :> b`
///
/// N.B., the type `a` is permitted to have unresolved inference
/// variables, but not the type `b`.
#[instrument(skip(self), level = "debug")]
pub(super) fn relate_types(
&mut self,
a: Ty<'tcx>,
v: ty::Variance,
b: Ty<'tcx>,
locations: Locations,
category: ConstraintCategory,
) -> Fallible<()> {
TypeRelating::new(
self.infcx,
NllTypeRelatingDelegate::new(self, locations, category, UniverseInfo::relate(a, b)),
v,
)
.relate(a, b)?;
Ok(())
}
}

struct NllTypeRelatingDelegate<'me, 'bccx, 'tcx> {
infcx: &'me InferCtxt<'me, 'tcx>,
borrowck_context: &'me mut BorrowCheckContext<'bccx, 'tcx>,

param_env: ty::ParamEnv<'tcx>,
type_checker: &'me mut TypeChecker<'bccx, 'tcx>,

/// Where (and why) is this relation taking place?
locations: Locations,
Expand All @@ -63,25 +53,24 @@ struct NllTypeRelatingDelegate<'me, 'bccx, 'tcx> {

impl NllTypeRelatingDelegate<'me, 'bccx, 'tcx> {
fn new(
infcx: &'me InferCtxt<'me, 'tcx>,
borrowck_context: &'me mut BorrowCheckContext<'bccx, 'tcx>,
param_env: ty::ParamEnv<'tcx>,
type_checker: &'me mut TypeChecker<'bccx, 'tcx>,
locations: Locations,
category: ConstraintCategory,
universe_info: UniverseInfo<'tcx>,
) -> Self {
Self { infcx, borrowck_context, param_env, locations, category, universe_info }
Self { type_checker, locations, category, universe_info }
}
}

impl TypeRelatingDelegate<'tcx> for NllTypeRelatingDelegate<'_, '_, 'tcx> {
fn param_env(&self) -> ty::ParamEnv<'tcx> {
self.param_env
self.type_checker.param_env
}

fn create_next_universe(&mut self) -> ty::UniverseIndex {
let universe = self.infcx.create_next_universe();
self.borrowck_context
let universe = self.type_checker.infcx.create_next_universe();
self.type_checker
.borrowck_context
.constraints
.universe_causes
.insert(universe, self.universe_info.clone());
Expand All @@ -90,15 +79,18 @@ impl TypeRelatingDelegate<'tcx> for NllTypeRelatingDelegate<'_, '_, 'tcx> {

fn next_existential_region_var(&mut self, from_forall: bool) -> ty::Region<'tcx> {
let origin = NllRegionVariableOrigin::Existential { from_forall };
self.infcx.next_nll_region_var(origin)
self.type_checker.infcx.next_nll_region_var(origin)
}

fn next_placeholder_region(&mut self, placeholder: ty::PlaceholderRegion) -> ty::Region<'tcx> {
self.borrowck_context.constraints.placeholder_region(self.infcx, placeholder)
self.type_checker
.borrowck_context
.constraints
.placeholder_region(self.type_checker.infcx, placeholder)
}

fn generalize_existential(&mut self, universe: ty::UniverseIndex) -> ty::Region<'tcx> {
self.infcx.next_nll_region_var_in_universe(
self.type_checker.infcx.next_nll_region_var_in_universe(
NllRegionVariableOrigin::Existential { from_forall: false },
universe,
)
Expand All @@ -110,15 +102,17 @@ impl TypeRelatingDelegate<'tcx> for NllTypeRelatingDelegate<'_, '_, 'tcx> {
sub: ty::Region<'tcx>,
info: ty::VarianceDiagInfo<'tcx>,
) {
let sub = self.borrowck_context.universal_regions.to_region_vid(sub);
let sup = self.borrowck_context.universal_regions.to_region_vid(sup);
self.borrowck_context.constraints.outlives_constraints.push(OutlivesConstraint {
sup,
sub,
locations: self.locations,
category: self.category,
variance_info: info,
});
let sub = self.type_checker.borrowck_context.universal_regions.to_region_vid(sub);
let sup = self.type_checker.borrowck_context.universal_regions.to_region_vid(sup);
self.type_checker.borrowck_context.constraints.outlives_constraints.push(
OutlivesConstraint {
sup,
sub,
locations: self.locations,
category: self.category,
variance_info: info,
},
);
}

// We don't have to worry about the equality of consts during borrow checking
Expand Down