diff --git a/compiler/rustc_hir_typeck/src/coercion.rs b/compiler/rustc_hir_typeck/src/coercion.rs index 642db3f36b586..bd0b98702983a 100644 --- a/compiler/rustc_hir_typeck/src/coercion.rs +++ b/compiler/rustc_hir_typeck/src/coercion.rs @@ -141,7 +141,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> { let at = self.at(&self.cause, self.fcx.param_env); let res = if self.use_lub { - at.lub(DefineOpaqueTypes::Yes, b, a) + at.lub(b, a) } else { at.sup(DefineOpaqueTypes::Yes, b, a) .map(|InferOk { value: (), obligations }| InferOk { value: b, obligations }) @@ -1190,13 +1190,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { (ty::FnDef(..), ty::FnDef(..)) => { // Don't reify if the function types have a LUB, i.e., they // are the same function and their parameters have a LUB. - match self.commit_if_ok(|_| { - self.at(cause, self.param_env).lub( - DefineOpaqueTypes::Yes, - prev_ty, - new_ty, - ) - }) { + match self + .commit_if_ok(|_| self.at(cause, self.param_env).lub(prev_ty, new_ty)) + { // We have a LUB of prev_ty and new_ty, just return it. Ok(ok) => return Ok(self.register_infer_ok_obligations(ok)), Err(_) => { @@ -1239,7 +1235,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { let (a_sig, b_sig) = self.normalize(new.span, (a_sig, b_sig)); let sig = self .at(cause, self.param_env) - .lub(DefineOpaqueTypes::Yes, a_sig, b_sig) + .lub(a_sig, b_sig) .map(|ok| self.register_infer_ok_obligations(ok))?; // Reify both sides and return the reified fn pointer type. @@ -1330,9 +1326,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { ); return Err(self - .commit_if_ok(|_| { - self.at(cause, self.param_env).lub(DefineOpaqueTypes::Yes, prev_ty, new_ty) - }) + .commit_if_ok(|_| self.at(cause, self.param_env).lub(prev_ty, new_ty)) .unwrap_err()); } } @@ -1344,13 +1338,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { Err(e) } else { Err(self - .commit_if_ok(|_| { - self.at(cause, self.param_env).lub( - DefineOpaqueTypes::Yes, - prev_ty, - new_ty, - ) - }) + .commit_if_ok(|_| self.at(cause, self.param_env).lub(prev_ty, new_ty)) .unwrap_err()) } } diff --git a/compiler/rustc_infer/src/infer/at.rs b/compiler/rustc_infer/src/infer/at.rs index 183973af4f9f3..5422761a6cf74 100644 --- a/compiler/rustc_infer/src/infer/at.rs +++ b/compiler/rustc_infer/src/infer/at.rs @@ -25,12 +25,13 @@ //! sometimes useful when the types of `c` and `d` are not traceable //! things. (That system should probably be refactored.) +use relate::lattice::{LatticeOp, LatticeOpKind}; use rustc_middle::bug; use rustc_middle::ty::{Const, ImplSubject}; use super::*; +use crate::infer::relate::type_relating::TypeRelating; use crate::infer::relate::{Relate, StructurallyRelateAliases, TypeRelation}; -use crate::traits::Obligation; /// Whether we should define opaque types or just treat them opaquely. /// @@ -108,14 +109,16 @@ impl<'a, 'tcx> At<'a, 'tcx> { where T: ToTrace<'tcx>, { - let mut fields = CombineFields::new( + let mut op = TypeRelating::new( self.infcx, ToTrace::to_trace(self.cause, expected, actual), self.param_env, define_opaque_types, + StructurallyRelateAliases::No, + ty::Contravariant, ); - fields.sup().relate(expected, actual)?; - Ok(InferOk { value: (), obligations: fields.into_obligations() }) + op.relate(expected, actual)?; + Ok(InferOk { value: (), obligations: op.into_obligations() }) } /// Makes `expected <: actual`. @@ -128,14 +131,16 @@ impl<'a, 'tcx> At<'a, 'tcx> { where T: ToTrace<'tcx>, { - let mut fields = CombineFields::new( + let mut op = TypeRelating::new( self.infcx, ToTrace::to_trace(self.cause, expected, actual), self.param_env, define_opaque_types, + StructurallyRelateAliases::No, + ty::Covariant, ); - fields.sub().relate(expected, actual)?; - Ok(InferOk { value: (), obligations: fields.into_obligations() }) + op.relate(expected, actual)?; + Ok(InferOk { value: (), obligations: op.into_obligations() }) } /// Makes `expected == actual`. @@ -167,45 +172,16 @@ impl<'a, 'tcx> At<'a, 'tcx> { where T: Relate>, { - let mut fields = CombineFields::new(self.infcx, trace, self.param_env, define_opaque_types); - fields.equate(StructurallyRelateAliases::No).relate(expected, actual)?; - Ok(InferOk { - value: (), - obligations: fields - .goals - .into_iter() - .map(|goal| { - Obligation::new( - self.infcx.tcx, - fields.trace.cause.clone(), - goal.param_env, - goal.predicate, - ) - }) - .collect(), - }) - } - - /// Equates `expected` and `found` while structurally relating aliases. - /// This should only be used inside of the next generation trait solver - /// when relating rigid aliases. - pub fn eq_structurally_relating_aliases( - self, - expected: T, - actual: T, - ) -> InferResult<'tcx, ()> - where - T: ToTrace<'tcx>, - { - assert!(self.infcx.next_trait_solver()); - let mut fields = CombineFields::new( + let mut op = TypeRelating::new( self.infcx, - ToTrace::to_trace(self.cause, expected, actual), + trace, self.param_env, - DefineOpaqueTypes::Yes, + define_opaque_types, + StructurallyRelateAliases::No, + ty::Invariant, ); - fields.equate(StructurallyRelateAliases::Yes).relate(expected, actual)?; - Ok(InferOk { value: (), obligations: fields.into_obligations() }) + op.relate(expected, actual)?; + Ok(InferOk { value: (), obligations: op.into_obligations() }) } pub fn relate( @@ -242,19 +218,16 @@ impl<'a, 'tcx> At<'a, 'tcx> { where T: Relate>, { - let mut fields = CombineFields::new( + let mut op = TypeRelating::new( self.infcx, TypeTrace::dummy(self.cause), self.param_env, DefineOpaqueTypes::Yes, - ); - fields.sub().relate_with_variance( + StructurallyRelateAliases::No, variance, - ty::VarianceDiagInfo::default(), - expected, - actual, - )?; - Ok(fields.goals) + ); + op.relate(expected, actual)?; + Ok(op.into_obligations().into_iter().map(|o| o.into()).collect()) } /// Used in the new solver since we don't care about tracking an `ObligationCause`. @@ -266,14 +239,16 @@ impl<'a, 'tcx> At<'a, 'tcx> { where T: Relate>, { - let mut fields = CombineFields::new( + let mut op = TypeRelating::new( self.infcx, TypeTrace::dummy(self.cause), self.param_env, DefineOpaqueTypes::Yes, + StructurallyRelateAliases::Yes, + ty::Invariant, ); - fields.equate(StructurallyRelateAliases::Yes).relate(expected, actual)?; - Ok(fields.goals) + op.relate(expected, actual)?; + Ok(op.into_obligations().into_iter().map(|o| o.into()).collect()) } /// Computes the least-upper-bound, or mutual supertype, of two @@ -281,45 +256,18 @@ impl<'a, 'tcx> At<'a, 'tcx> { /// this can result in an error (e.g., if asked to compute LUB of /// u32 and i32), it is meaningful to call one of them the /// "expected type". - pub fn lub( - self, - define_opaque_types: DefineOpaqueTypes, - expected: T, - actual: T, - ) -> InferResult<'tcx, T> + pub fn lub(self, expected: T, actual: T) -> InferResult<'tcx, T> where T: ToTrace<'tcx>, { - let mut fields = CombineFields::new( + let mut op = LatticeOp::new( self.infcx, ToTrace::to_trace(self.cause, expected, actual), self.param_env, - define_opaque_types, - ); - let value = fields.lub().relate(expected, actual)?; - Ok(InferOk { value, obligations: fields.into_obligations() }) - } - - /// Computes the greatest-lower-bound, or mutual subtype, of two - /// values. As with `lub` order doesn't matter, except for error - /// cases. - pub fn glb( - self, - define_opaque_types: DefineOpaqueTypes, - expected: T, - actual: T, - ) -> InferResult<'tcx, T> - where - T: ToTrace<'tcx>, - { - let mut fields = CombineFields::new( - self.infcx, - ToTrace::to_trace(self.cause, expected, actual), - self.param_env, - define_opaque_types, + LatticeOpKind::Lub, ); - let value = fields.glb().relate(expected, actual)?; - Ok(InferOk { value, obligations: fields.into_obligations() }) + let value = op.relate(expected, actual)?; + Ok(InferOk { value, obligations: op.into_obligations() }) } } diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs index e7bd2562a4f4a..cb60d9f286b13 100644 --- a/compiler/rustc_infer/src/infer/mod.rs +++ b/compiler/rustc_infer/src/infer/mod.rs @@ -14,7 +14,6 @@ use region_constraints::{ GenericKind, RegionConstraintCollector, RegionConstraintStorage, VarInfos, VerifyBound, }; pub use relate::StructurallyRelateAliases; -use relate::combine::CombineFields; pub use relate::combine::PredicateEmittingRelation; use rustc_data_structures::captures::Captures; use rustc_data_structures::fx::{FxHashSet, FxIndexMap}; diff --git a/compiler/rustc_infer/src/infer/relate/combine.rs b/compiler/rustc_infer/src/infer/relate/combine.rs index 450437f217647..c4f5a85a8bee7 100644 --- a/compiler/rustc_infer/src/infer/relate/combine.rs +++ b/compiler/rustc_infer/src/infer/relate/combine.rs @@ -1,4 +1,4 @@ -//! There are four type combiners: [TypeRelating], `Lub`, and `Glb`, +//! There are four type combiners: `TypeRelating`, `Lub`, and `Glb`, //! and `NllTypeRelating` in rustc_borrowck, which is only used for NLL. //! //! Each implements the trait [TypeRelation] and contains methods for @@ -20,56 +20,13 @@ use rustc_middle::bug; use rustc_middle::infer::unify_key::EffectVarValue; -use rustc_middle::traits::solve::Goal; use rustc_middle::ty::error::{ExpectedFound, TypeError}; -use rustc_middle::ty::{self, InferConst, IntType, Ty, TyCtxt, TypeVisitableExt, UintType, Upcast}; +use rustc_middle::ty::{self, InferConst, IntType, Ty, TypeVisitableExt, UintType}; pub use rustc_next_trait_solver::relate::combine::*; use tracing::debug; -use super::lattice::{LatticeOp, LatticeOpKind}; -use super::type_relating::TypeRelating; use super::{RelateResult, StructurallyRelateAliases}; -use crate::infer::{DefineOpaqueTypes, InferCtxt, TypeTrace, relate}; -use crate::traits::{Obligation, PredicateObligation}; - -#[derive(Clone)] -pub(crate) struct CombineFields<'infcx, 'tcx> { - pub infcx: &'infcx InferCtxt<'tcx>, - // Immutable fields - pub trace: TypeTrace<'tcx>, - pub param_env: ty::ParamEnv<'tcx>, - pub define_opaque_types: DefineOpaqueTypes, - // Mutable fields - // - // Adding any additional field likely requires - // changes to the cache of `TypeRelating`. - pub goals: Vec>>, -} - -impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> { - pub(crate) fn new( - infcx: &'infcx InferCtxt<'tcx>, - trace: TypeTrace<'tcx>, - param_env: ty::ParamEnv<'tcx>, - define_opaque_types: DefineOpaqueTypes, - ) -> Self { - Self { infcx, trace, param_env, define_opaque_types, goals: vec![] } - } - - pub(crate) fn into_obligations(self) -> Vec> { - self.goals - .into_iter() - .map(|goal| { - Obligation::new( - self.infcx.tcx, - self.trace.cause.clone(), - goal.param_env, - goal.predicate, - ) - }) - .collect() - } -} +use crate::infer::{InferCtxt, relate}; impl<'tcx> InferCtxt<'tcx> { pub fn super_combine_tys( @@ -281,50 +238,3 @@ impl<'tcx> InferCtxt<'tcx> { val } } - -impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> { - pub(crate) fn tcx(&self) -> TyCtxt<'tcx> { - self.infcx.tcx - } - - pub(crate) fn equate<'a>( - &'a mut self, - structurally_relate_aliases: StructurallyRelateAliases, - ) -> TypeRelating<'a, 'infcx, 'tcx> { - TypeRelating::new(self, structurally_relate_aliases, ty::Invariant) - } - - pub(crate) fn sub<'a>(&'a mut self) -> TypeRelating<'a, 'infcx, 'tcx> { - TypeRelating::new(self, StructurallyRelateAliases::No, ty::Covariant) - } - - pub(crate) fn sup<'a>(&'a mut self) -> TypeRelating<'a, 'infcx, 'tcx> { - TypeRelating::new(self, StructurallyRelateAliases::No, ty::Contravariant) - } - - pub(crate) fn lub<'a>(&'a mut self) -> LatticeOp<'a, 'infcx, 'tcx> { - LatticeOp::new(self, LatticeOpKind::Lub) - } - - pub(crate) fn glb<'a>(&'a mut self) -> LatticeOp<'a, 'infcx, 'tcx> { - LatticeOp::new(self, LatticeOpKind::Glb) - } - - pub(crate) fn register_obligations( - &mut self, - obligations: impl IntoIterator>>, - ) { - self.goals.extend(obligations); - } - - pub(crate) fn register_predicates( - &mut self, - obligations: impl IntoIterator, ty::Predicate<'tcx>>>, - ) { - self.goals.extend( - obligations - .into_iter() - .map(|to_pred| Goal::new(self.infcx.tcx, self.param_env, to_pred)), - ) - } -} diff --git a/compiler/rustc_infer/src/infer/relate/lattice.rs b/compiler/rustc_infer/src/infer/relate/lattice.rs index 9564baa6ab287..8cec312abf75b 100644 --- a/compiler/rustc_infer/src/infer/relate/lattice.rs +++ b/compiler/rustc_infer/src/infer/relate/lattice.rs @@ -24,8 +24,9 @@ use rustc_span::Span; use tracing::{debug, instrument}; use super::StructurallyRelateAliases; -use super::combine::{CombineFields, PredicateEmittingRelation}; -use crate::infer::{DefineOpaqueTypes, InferCtxt, SubregionOrigin}; +use super::combine::PredicateEmittingRelation; +use crate::infer::{DefineOpaqueTypes, InferCtxt, SubregionOrigin, TypeTrace}; +use crate::traits::{Obligation, PredicateObligation}; #[derive(Clone, Copy)] pub(crate) enum LatticeOpKind { @@ -43,23 +44,34 @@ impl LatticeOpKind { } /// A greatest lower bound" (common subtype) or least upper bound (common supertype). -pub(crate) struct LatticeOp<'combine, 'infcx, 'tcx> { - fields: &'combine mut CombineFields<'infcx, 'tcx>, +pub(crate) struct LatticeOp<'infcx, 'tcx> { + infcx: &'infcx InferCtxt<'tcx>, + // Immutable fields + trace: TypeTrace<'tcx>, + param_env: ty::ParamEnv<'tcx>, + // Mutable fields kind: LatticeOpKind, + obligations: Vec>, } -impl<'combine, 'infcx, 'tcx> LatticeOp<'combine, 'infcx, 'tcx> { +impl<'infcx, 'tcx> LatticeOp<'infcx, 'tcx> { pub(crate) fn new( - fields: &'combine mut CombineFields<'infcx, 'tcx>, + infcx: &'infcx InferCtxt<'tcx>, + trace: TypeTrace<'tcx>, + param_env: ty::ParamEnv<'tcx>, kind: LatticeOpKind, - ) -> LatticeOp<'combine, 'infcx, 'tcx> { - LatticeOp { fields, kind } + ) -> LatticeOp<'infcx, 'tcx> { + LatticeOp { infcx, trace, param_env, kind, obligations: vec![] } + } + + pub(crate) fn into_obligations(self) -> Vec> { + self.obligations } } -impl<'tcx> TypeRelation> for LatticeOp<'_, '_, 'tcx> { +impl<'tcx> TypeRelation> for LatticeOp<'_, 'tcx> { fn cx(&self) -> TyCtxt<'tcx> { - self.fields.tcx() + self.infcx.tcx } fn relate_with_variance>>( @@ -70,7 +82,15 @@ impl<'tcx> TypeRelation> for LatticeOp<'_, '_, 'tcx> { b: T, ) -> RelateResult<'tcx, T> { match variance { - ty::Invariant => self.fields.equate(StructurallyRelateAliases::No).relate(a, b), + ty::Invariant => { + self.obligations.extend( + self.infcx + .at(&self.trace.cause, self.param_env) + .eq_trace(DefineOpaqueTypes::Yes, self.trace.clone(), a, b)? + .into_obligations(), + ); + Ok(a) + } ty::Covariant => self.relate(a, b), // FIXME(#41044) -- not correct, need test ty::Bivariant => Ok(a), @@ -90,7 +110,7 @@ impl<'tcx> TypeRelation> for LatticeOp<'_, '_, 'tcx> { return Ok(a); } - let infcx = self.fields.infcx; + let infcx = self.infcx; let a = infcx.shallow_resolve(a); let b = infcx.shallow_resolve(b); @@ -115,12 +135,12 @@ impl<'tcx> TypeRelation> for LatticeOp<'_, '_, 'tcx> { // iterate on the subtype obligations that are returned, but I // think this suffices. -nmatsakis (&ty::Infer(TyVar(..)), _) => { - let v = infcx.next_ty_var(self.fields.trace.cause.span); + let v = infcx.next_ty_var(self.trace.cause.span); self.relate_bound(v, b, a)?; Ok(v) } (_, &ty::Infer(TyVar(..))) => { - let v = infcx.next_ty_var(self.fields.trace.cause.span); + let v = infcx.next_ty_var(self.trace.cause.span); self.relate_bound(v, a, b)?; Ok(v) } @@ -132,9 +152,7 @@ impl<'tcx> TypeRelation> for LatticeOp<'_, '_, 'tcx> { (&ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }), _) | (_, &ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. })) - if self.fields.define_opaque_types == DefineOpaqueTypes::Yes - && def_id.is_local() - && !infcx.next_trait_solver() => + if def_id.is_local() && !infcx.next_trait_solver() => { self.register_goals(infcx.handle_opaque_type( a, @@ -155,8 +173,8 @@ impl<'tcx> TypeRelation> for LatticeOp<'_, '_, 'tcx> { a: ty::Region<'tcx>, b: ty::Region<'tcx>, ) -> RelateResult<'tcx, ty::Region<'tcx>> { - let origin = SubregionOrigin::Subtype(Box::new(self.fields.trace.clone())); - let mut inner = self.fields.infcx.inner.borrow_mut(); + let origin = SubregionOrigin::Subtype(Box::new(self.trace.clone())); + let mut inner = self.infcx.inner.borrow_mut(); let mut constraints = inner.unwrap_region_constraints(); Ok(match self.kind { // GLB(&'static u8, &'a u8) == &RegionLUB('static, 'a) u8 == &'static u8 @@ -173,7 +191,7 @@ impl<'tcx> TypeRelation> for LatticeOp<'_, '_, 'tcx> { a: ty::Const<'tcx>, b: ty::Const<'tcx>, ) -> RelateResult<'tcx, ty::Const<'tcx>> { - self.fields.infcx.super_combine_consts(self, a, b) + self.infcx.super_combine_consts(self, a, b) } fn binders( @@ -202,7 +220,7 @@ impl<'tcx> TypeRelation> for LatticeOp<'_, '_, 'tcx> { } } -impl<'combine, 'infcx, 'tcx> LatticeOp<'combine, 'infcx, 'tcx> { +impl<'infcx, 'tcx> LatticeOp<'infcx, 'tcx> { // Relates the type `v` to `a` and `b` such that `v` represents // the LUB/GLB of `a` and `b` as appropriate. // @@ -210,24 +228,24 @@ impl<'combine, 'infcx, 'tcx> LatticeOp<'combine, 'infcx, 'tcx> { // relates `v` to `a` first, which may help us to avoid unnecessary // type variable obligations. See caller for details. fn relate_bound(&mut self, v: Ty<'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, ()> { - let mut sub = self.fields.sub(); + let at = self.infcx.at(&self.trace.cause, self.param_env); match self.kind { LatticeOpKind::Glb => { - sub.relate(v, a)?; - sub.relate(v, b)?; + self.obligations.extend(at.sub(DefineOpaqueTypes::Yes, v, a)?.into_obligations()); + self.obligations.extend(at.sub(DefineOpaqueTypes::Yes, v, b)?.into_obligations()); } LatticeOpKind::Lub => { - sub.relate(a, v)?; - sub.relate(b, v)?; + self.obligations.extend(at.sub(DefineOpaqueTypes::Yes, a, v)?.into_obligations()); + self.obligations.extend(at.sub(DefineOpaqueTypes::Yes, b, v)?.into_obligations()); } } Ok(()) } } -impl<'tcx> PredicateEmittingRelation> for LatticeOp<'_, '_, 'tcx> { +impl<'tcx> PredicateEmittingRelation> for LatticeOp<'_, 'tcx> { fn span(&self) -> Span { - self.fields.trace.span() + self.trace.span() } fn structurally_relate_aliases(&self) -> StructurallyRelateAliases { @@ -235,21 +253,27 @@ impl<'tcx> PredicateEmittingRelation> for LatticeOp<'_, '_, 'tcx } fn param_env(&self) -> ty::ParamEnv<'tcx> { - self.fields.param_env + self.param_env } fn register_predicates( &mut self, - obligations: impl IntoIterator, ty::Predicate<'tcx>>>, + preds: impl IntoIterator, ty::Predicate<'tcx>>>, ) { - self.fields.register_predicates(obligations); + self.obligations.extend(preds.into_iter().map(|pred| { + Obligation::new(self.infcx.tcx, self.trace.cause.clone(), self.param_env, pred) + })) } - fn register_goals( - &mut self, - obligations: impl IntoIterator>>, - ) { - self.fields.register_obligations(obligations); + fn register_goals(&mut self, goals: impl IntoIterator>>) { + self.obligations.extend(goals.into_iter().map(|goal| { + Obligation::new( + self.infcx.tcx, + self.trace.cause.clone(), + goal.param_env, + goal.predicate, + ) + })) } fn register_alias_relate_predicate(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) { diff --git a/compiler/rustc_infer/src/infer/relate/mod.rs b/compiler/rustc_infer/src/infer/relate/mod.rs index 85158faa65d13..baab5bb274a09 100644 --- a/compiler/rustc_infer/src/infer/relate/mod.rs +++ b/compiler/rustc_infer/src/infer/relate/mod.rs @@ -11,5 +11,5 @@ pub use self::combine::PredicateEmittingRelation; pub(super) mod combine; mod generalize; mod higher_ranked; -mod lattice; -mod type_relating; +pub(super) mod lattice; +pub(super) mod type_relating; diff --git a/compiler/rustc_infer/src/infer/relate/type_relating.rs b/compiler/rustc_infer/src/infer/relate/type_relating.rs index 7537ceec307a3..4b4b13e919cea 100644 --- a/compiler/rustc_infer/src/infer/relate/type_relating.rs +++ b/compiler/rustc_infer/src/infer/relate/type_relating.rs @@ -7,29 +7,31 @@ use rustc_span::Span; use rustc_type_ir::data_structures::DelayedSet; use tracing::{debug, instrument}; -use super::combine::CombineFields; use crate::infer::BoundRegionConversionTime::HigherRankedType; use crate::infer::relate::{PredicateEmittingRelation, StructurallyRelateAliases}; -use crate::infer::{DefineOpaqueTypes, InferCtxt, SubregionOrigin}; +use crate::infer::{DefineOpaqueTypes, InferCtxt, SubregionOrigin, TypeTrace}; +use crate::traits::{Obligation, PredicateObligation}; /// Enforce that `a` is equal to or a subtype of `b`. -pub(crate) struct TypeRelating<'combine, 'a, 'tcx> { - // Immutable except for the `InferCtxt` and the - // resulting nested `goals`. - fields: &'combine mut CombineFields<'a, 'tcx>, +pub(crate) struct TypeRelating<'infcx, 'tcx> { + infcx: &'infcx InferCtxt<'tcx>, - // Immutable field. + // Immutable fields + trace: TypeTrace<'tcx>, + param_env: ty::ParamEnv<'tcx>, + define_opaque_types: DefineOpaqueTypes, structurally_relate_aliases: StructurallyRelateAliases, - // Mutable field. - ambient_variance: ty::Variance, + // Mutable fields. + ambient_variance: ty::Variance, + obligations: Vec>, /// The cache only tracks the `ambient_variance` as it's the /// only field which is mutable and which meaningfully changes /// the result when relating types. /// /// The cache does not track whether the state of the /// `InferCtxt` has been changed or whether we've added any - /// obligations to `self.fields.goals`. Whether a goal is added + /// obligations to `self.goals`. Whether a goal is added /// once or multiple times is not really meaningful. /// /// Changes in the inference state may delay some type inference to @@ -48,24 +50,35 @@ pub(crate) struct TypeRelating<'combine, 'a, 'tcx> { cache: DelayedSet<(ty::Variance, Ty<'tcx>, Ty<'tcx>)>, } -impl<'combine, 'infcx, 'tcx> TypeRelating<'combine, 'infcx, 'tcx> { +impl<'infcx, 'tcx> TypeRelating<'infcx, 'tcx> { pub(crate) fn new( - f: &'combine mut CombineFields<'infcx, 'tcx>, + infcx: &'infcx InferCtxt<'tcx>, + trace: TypeTrace<'tcx>, + param_env: ty::ParamEnv<'tcx>, + define_opaque_types: DefineOpaqueTypes, structurally_relate_aliases: StructurallyRelateAliases, ambient_variance: ty::Variance, - ) -> TypeRelating<'combine, 'infcx, 'tcx> { + ) -> TypeRelating<'infcx, 'tcx> { TypeRelating { - fields: f, + infcx, + trace, + param_env, + define_opaque_types, structurally_relate_aliases, ambient_variance, + obligations: vec![], cache: Default::default(), } } + + pub(crate) fn into_obligations(self) -> Vec> { + self.obligations + } } -impl<'tcx> TypeRelation> for TypeRelating<'_, '_, 'tcx> { +impl<'tcx> TypeRelation> for TypeRelating<'_, 'tcx> { fn cx(&self) -> TyCtxt<'tcx> { - self.fields.infcx.tcx + self.infcx.tcx } fn relate_item_args( @@ -109,7 +122,7 @@ impl<'tcx> TypeRelation> for TypeRelating<'_, '_, 'tcx> { return Ok(a); } - let infcx = self.fields.infcx; + let infcx = self.infcx; let a = infcx.shallow_resolve(a); let b = infcx.shallow_resolve(b); @@ -123,9 +136,10 @@ impl<'tcx> TypeRelation> for TypeRelating<'_, '_, 'tcx> { ty::Covariant => { // can't make progress on `A <: B` if both A and B are // type variables, so record an obligation. - self.fields.goals.push(Goal::new( + self.obligations.push(Obligation::new( self.cx(), - self.fields.param_env, + self.trace.cause.clone(), + self.param_env, ty::Binder::dummy(ty::PredicateKind::Subtype(ty::SubtypePredicate { a_is_expected: true, a, @@ -136,9 +150,10 @@ impl<'tcx> TypeRelation> for TypeRelating<'_, '_, 'tcx> { ty::Contravariant => { // can't make progress on `B <: A` if both A and B are // type variables, so record an obligation. - self.fields.goals.push(Goal::new( + self.obligations.push(Obligation::new( self.cx(), - self.fields.param_env, + self.trace.cause.clone(), + self.param_env, ty::Binder::dummy(ty::PredicateKind::Subtype(ty::SubtypePredicate { a_is_expected: false, a: b, @@ -182,14 +197,14 @@ impl<'tcx> TypeRelation> for TypeRelating<'_, '_, 'tcx> { (&ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }), _) | (_, &ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. })) - if self.fields.define_opaque_types == DefineOpaqueTypes::Yes + if self.define_opaque_types == DefineOpaqueTypes::Yes && def_id.is_local() && !infcx.next_trait_solver() => { - self.fields.goals.extend(infcx.handle_opaque_type( + self.register_goals(infcx.handle_opaque_type( a, b, - self.fields.trace.cause.span, + self.trace.cause.span, self.param_env(), )?); } @@ -210,13 +225,12 @@ impl<'tcx> TypeRelation> for TypeRelating<'_, '_, 'tcx> { a: ty::Region<'tcx>, b: ty::Region<'tcx>, ) -> RelateResult<'tcx, ty::Region<'tcx>> { - let origin = SubregionOrigin::Subtype(Box::new(self.fields.trace.clone())); + let origin = SubregionOrigin::Subtype(Box::new(self.trace.clone())); match self.ambient_variance { // Subtype(&'a u8, &'b u8) => Outlives('a: 'b) => SubRegion('b, 'a) ty::Covariant => { - self.fields - .infcx + self.infcx .inner .borrow_mut() .unwrap_region_constraints() @@ -224,16 +238,14 @@ impl<'tcx> TypeRelation> for TypeRelating<'_, '_, 'tcx> { } // Suptype(&'a u8, &'b u8) => Outlives('b: 'a) => SubRegion('a, 'b) ty::Contravariant => { - self.fields - .infcx + self.infcx .inner .borrow_mut() .unwrap_region_constraints() .make_subregion(origin, a, b); } ty::Invariant => { - self.fields - .infcx + self.infcx .inner .borrow_mut() .unwrap_region_constraints() @@ -253,7 +265,7 @@ impl<'tcx> TypeRelation> for TypeRelating<'_, '_, 'tcx> { a: ty::Const<'tcx>, b: ty::Const<'tcx>, ) -> RelateResult<'tcx, ty::Const<'tcx>> { - self.fields.infcx.super_combine_consts(self, a, b) + self.infcx.super_combine_consts(self, a, b) } fn binders( @@ -271,8 +283,8 @@ impl<'tcx> TypeRelation> for TypeRelating<'_, '_, 'tcx> { { self.relate(a, b)?; } else { - let span = self.fields.trace.cause.span; - let infcx = self.fields.infcx; + let span = self.trace.cause.span; + let infcx = self.infcx; match self.ambient_variance { // Checks whether `for<..> sub <: for<..> sup` holds. @@ -335,13 +347,13 @@ impl<'tcx> TypeRelation> for TypeRelating<'_, '_, 'tcx> { } } -impl<'tcx> PredicateEmittingRelation> for TypeRelating<'_, '_, 'tcx> { +impl<'tcx> PredicateEmittingRelation> for TypeRelating<'_, 'tcx> { fn span(&self) -> Span { - self.fields.trace.span() + self.trace.span() } fn param_env(&self) -> ty::ParamEnv<'tcx> { - self.fields.param_env + self.param_env } fn structurally_relate_aliases(&self) -> StructurallyRelateAliases { @@ -350,16 +362,22 @@ impl<'tcx> PredicateEmittingRelation> for TypeRelating<'_, '_, ' fn register_predicates( &mut self, - obligations: impl IntoIterator, ty::Predicate<'tcx>>>, + preds: impl IntoIterator, ty::Predicate<'tcx>>>, ) { - self.fields.register_predicates(obligations); + self.obligations.extend(preds.into_iter().map(|pred| { + Obligation::new(self.infcx.tcx, self.trace.cause.clone(), self.param_env, pred) + })) } - fn register_goals( - &mut self, - obligations: impl IntoIterator>>, - ) { - self.fields.register_obligations(obligations); + fn register_goals(&mut self, goals: impl IntoIterator>>) { + self.obligations.extend(goals.into_iter().map(|goal| { + Obligation::new( + self.infcx.tcx, + self.trace.cause.clone(), + goal.param_env, + goal.predicate, + ) + })) } fn register_alias_relate_predicate(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) {