Move type relations into submodule in rustc_infer

11 files changed, 42 insertions, 41 deletions

diff --git a/compiler/rustc_infer/src/infer/higher_ranked/mod.rs b/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
index 510b1797d3c..0de988efaee 100644
--- a/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
+++ b/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
@@ -1,8 +1,8 @@
 //! Helper routines for higher-ranked things. See the `doc` module at
 //! the end of the file for details.
 
-use super::combine::CombineFields;
 use super::{HigherRankedType, InferCtxt};
+use crate::infer::relate::combine::CombineFields;
 use crate::infer::CombinedSnapshot;
 use rustc_middle::ty::fold::FnMutDelegate;
 use rustc_middle::ty::relate::{Relate, RelateResult, TypeRelation};
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index e8a8808428c..5aa9c82b3ca 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -5,7 +5,7 @@ pub use self::BoundRegionConversionTime::*;
 pub use self::RegionVariableOrigin::*;
 pub use self::SubregionOrigin::*;
 pub use self::ValuePairs::*;
-pub use combine::ObligationEmittingRelation;
+pub use relate::combine::ObligationEmittingRelation;
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::undo_log::UndoLogs;
 use rustc_middle::infer::unify_key::{ConstVidKey, EffectVidKey};
@@ -43,7 +43,6 @@ use rustc_span::{Span, DUMMY_SP};
 use std::cell::{Cell, RefCell};
 use std::fmt;
 
-use self::combine::CombineFields;
 use self::error_reporting::TypeErrCtxt;
 use self::free_regions::RegionRelations;
 use self::lexical_region_resolve::LexicalRegionResolutions;
@@ -51,29 +50,24 @@ use self::region_constraints::{GenericKind, VarInfos, VerifyBound};
 use self::region_constraints::{
     RegionConstraintCollector, RegionConstraintStorage, RegionSnapshot,
 };
+pub use self::relate::combine::CombineFields;
 use self::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 
 pub mod at;
 pub mod canonical;
-mod combine;
-mod equate;
 pub mod error_reporting;
 pub mod free_regions;
 mod freshen;
 mod fudge;
-mod generalize;
-mod glb;
 mod higher_ranked;
-pub mod lattice;
 mod lexical_region_resolve;
-mod lub;
 pub mod nll_relate;
 pub mod opaque_types;
 pub mod outlives;
 mod projection;
 pub mod region_constraints;
+mod relate;
 pub mod resolve;
-mod sub;
 pub mod type_variable;
 mod undo_log;
 
diff --git a/compiler/rustc_infer/src/infer/nll_relate/mod.rs b/compiler/rustc_infer/src/infer/nll_relate/mod.rs
index ab3c976a351..a4af9c8f6b2 100644
--- a/compiler/rustc_infer/src/infer/nll_relate/mod.rs
+++ b/compiler/rustc_infer/src/infer/nll_relate/mod.rs
@@ -30,8 +30,8 @@ use rustc_middle::ty::{self, InferConst, Ty, TyCtxt};
 use rustc_span::{Span, Symbol};
 use std::fmt::Debug;
 
-use crate::infer::combine::ObligationEmittingRelation;
-use crate::infer::generalize::{self, Generalization};
+use super::relate::combine::ObligationEmittingRelation;
+use super::relate::generalize::{self, Generalization};
 use crate::infer::InferCtxt;
 use crate::infer::{TypeVariableOrigin, TypeVariableOriginKind};
 use crate::traits::{Obligation, PredicateObligations};
diff --git a/compiler/rustc_infer/src/infer/combine.rs b/compiler/rustc_infer/src/infer/relate/combine.rs
index fe58fc7122c..043a916679e 100644
--- a/compiler/rustc_infer/src/infer/combine.rs
+++ b/compiler/rustc_infer/src/infer/relate/combine.rs
@@ -3,7 +3,7 @@
 //! combining two instances of various things and yielding a new instance.
 //! These combiner methods always yield a `Result<T>`. To relate two
 //! types, you can use `infcx.at(cause, param_env)` which then allows
-//! you to use the relevant methods of [At](super::at::At).
+//! you to use the relevant methods of [At](crate::infer::at::At).
 //!
 //! Combiners mostly do their specific behavior and then hand off the
 //! bulk of the work to [InferCtxt::super_combine_tys] and
@@ -23,11 +23,11 @@
 //! this should be correctly updated.
 
 use super::equate::Equate;
+use super::generalize::{self, CombineDelegate, Generalization};
 use super::glb::Glb;
 use super::lub::Lub;
 use super::sub::Sub;
-use super::{DefineOpaqueTypes, InferCtxt, TypeTrace};
-use crate::infer::generalize::{self, CombineDelegate, Generalization};
+use crate::infer::{DefineOpaqueTypes, InferCtxt, TypeTrace};
 use crate::traits::{Obligation, PredicateObligations};
 use rustc_middle::infer::canonical::OriginalQueryValues;
 use rustc_middle::infer::unify_key::{ConstVarValue, ConstVariableValue, EffectVarValue};
diff --git a/compiler/rustc_infer/src/infer/equate.rs b/compiler/rustc_infer/src/infer/relate/equate.rs
index 5d929394eb0..9943c638a91 100644
--- a/compiler/rustc_infer/src/infer/equate.rs
+++ b/compiler/rustc_infer/src/infer/relate/equate.rs
@@ -1,8 +1,6 @@
-use crate::infer::DefineOpaqueTypes;
-use crate::traits::PredicateObligations;
-
 use super::combine::{CombineFields, ObligationEmittingRelation};
-use super::Subtype;
+use crate::infer::{DefineOpaqueTypes, SubregionOrigin};
+use crate::traits::PredicateObligations;
 
 use rustc_middle::ty::relate::{self, Relate, RelateResult, TypeRelation};
 use rustc_middle::ty::GenericArgsRef;
@@ -133,7 +131,7 @@ impl<'tcx> TypeRelation<'tcx> for Equate<'_, '_, 'tcx> {
         b: ty::Region<'tcx>,
     ) -> RelateResult<'tcx, ty::Region<'tcx>> {
         debug!("{}.regions({:?}, {:?})", self.tag(), a, b);
-        let origin = Subtype(Box::new(self.fields.trace.clone()));
+        let origin = SubregionOrigin::Subtype(Box::new(self.fields.trace.clone()));
         self.fields
             .infcx
             .inner
diff --git a/compiler/rustc_infer/src/infer/generalize.rs b/compiler/rustc_infer/src/infer/relate/generalize.rs
index 383f3bdbe23..66f7b08ee12 100644
--- a/compiler/rustc_infer/src/infer/generalize.rs
+++ b/compiler/rustc_infer/src/infer/relate/generalize.rs
@@ -16,7 +16,7 @@ use crate::infer::{InferCtxt, RegionVariableOrigin};
 /// Attempts to generalize `term` for the type variable `for_vid`.
 /// This checks for cycles -- that is, whether the type `term`
 /// references `for_vid`.
-pub(super) fn generalize<'tcx, D: GeneralizerDelegate<'tcx>, T: Into<Term<'tcx>> + Relate<'tcx>>(
+pub fn generalize<'tcx, D: GeneralizerDelegate<'tcx>, T: Into<Term<'tcx>> + Relate<'tcx>>(
     infcx: &InferCtxt<'tcx>,
     delegate: &mut D,
     term: T,
@@ -54,7 +54,7 @@ pub(super) fn generalize<'tcx, D: GeneralizerDelegate<'tcx>, T: Into<Term<'tcx>>
 
 /// Abstracts the handling of region vars between HIR and MIR/NLL typechecking
 /// in the generalizer code.
-pub(super) trait GeneralizerDelegate<'tcx> {
+pub trait GeneralizerDelegate<'tcx> {
     fn param_env(&self) -> ty::ParamEnv<'tcx>;
 
     fn forbid_inference_vars() -> bool;
@@ -64,7 +64,7 @@ pub(super) trait GeneralizerDelegate<'tcx> {
     fn generalize_region(&mut self, universe: ty::UniverseIndex) -> ty::Region<'tcx>;
 }
 
-pub(super) struct CombineDelegate<'cx, 'tcx> {
+pub struct CombineDelegate<'cx, 'tcx> {
     pub infcx: &'cx InferCtxt<'tcx>,
     pub param_env: ty::ParamEnv<'tcx>,
     pub span: Span,
@@ -515,7 +515,7 @@ where
 /// not only the generalized type, but also a bool flag
 /// indicating whether further WF checks are needed.
 #[derive(Debug)]
-pub(super) struct Generalization<T> {
+pub struct Generalization<T> {
     /// When generalizing `<?0 as Trait>::Assoc` or
     /// `<T as Bar<<?0 as Foo>::Assoc>>::Assoc`
     /// for `?0` generalization returns an inference
@@ -524,7 +524,7 @@ pub(super) struct Generalization<T> {
     /// This has to be handled wotj care as it can
     /// otherwise very easily result in infinite
     /// recursion.
-    pub(super) value_may_be_infer: T,
+    pub value_may_be_infer: T,
 
     /// If true, then the generalized type may not be well-formed,
     /// even if the source type is well-formed, so we should add an
@@ -551,5 +551,5 @@ pub(super) struct Generalization<T> {
     /// will force the calling code to check that `WF(Foo<?C, ?D>)`
     /// holds, which in turn implies that `?C::Item == ?D`. So once
     /// `?C` is constrained, that should suffice to restrict `?D`.
-    pub(super) needs_wf: bool,
+    pub needs_wf: bool,
 }
diff --git a/compiler/rustc_infer/src/infer/glb.rs b/compiler/rustc_infer/src/infer/relate/glb.rs
index 2f659d9a665..6a3413879c4 100644
--- a/compiler/rustc_infer/src/infer/glb.rs
+++ b/compiler/rustc_infer/src/infer/relate/glb.rs
@@ -1,13 +1,12 @@
 //! Greatest lower bound. See [`lattice`].
 
+use rustc_middle::ty::relate::{Relate, RelateResult, TypeRelation};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
+
 use super::combine::{CombineFields, ObligationEmittingRelation};
 use super::lattice::{self, LatticeDir};
-use super::Subtype;
-use super::{DefineOpaqueTypes, InferCtxt};
-
+use crate::infer::{DefineOpaqueTypes, InferCtxt, SubregionOrigin};
 use crate::traits::{ObligationCause, PredicateObligations};
-use rustc_middle::ty::relate::{Relate, RelateResult, TypeRelation};
-use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
 
 /// "Greatest lower bound" (common subtype)
 pub struct Glb<'combine, 'infcx, 'tcx> {
@@ -68,7 +67,7 @@ impl<'tcx> TypeRelation<'tcx> for Glb<'_, '_, 'tcx> {
     ) -> RelateResult<'tcx, ty::Region<'tcx>> {
         debug!("{}.regions({:?}, {:?})", self.tag(), a, b);
 
-        let origin = Subtype(Box::new(self.fields.trace.clone()));
+        let origin = SubregionOrigin::Subtype(Box::new(self.fields.trace.clone()));
         // GLB(&'static u8, &'a u8) == &RegionLUB('static, 'a) u8 == &'static u8
         Ok(self.fields.infcx.inner.borrow_mut().unwrap_region_constraints().lub_regions(
             self.tcx(),
diff --git a/compiler/rustc_infer/src/infer/lattice.rs b/compiler/rustc_infer/src/infer/relate/lattice.rs
index 9ef35429fe3..744e2dfa380 100644
--- a/compiler/rustc_infer/src/infer/lattice.rs
+++ b/compiler/rustc_infer/src/infer/relate/lattice.rs
@@ -18,10 +18,10 @@
 //! [lattices]: https://en.wikipedia.org/wiki/Lattice_(order)
 
 use super::combine::ObligationEmittingRelation;
-use super::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
-use super::{DefineOpaqueTypes, InferCtxt};
-
+use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
+use crate::infer::{DefineOpaqueTypes, InferCtxt};
 use crate::traits::ObligationCause;
+
 use rustc_middle::ty::relate::RelateResult;
 use rustc_middle::ty::TyVar;
 use rustc_middle::ty::{self, Ty};
diff --git a/compiler/rustc_infer/src/infer/lub.rs b/compiler/rustc_infer/src/infer/relate/lub.rs
index e41ec7e6c01..41cd98ed0cf 100644
--- a/compiler/rustc_infer/src/infer/lub.rs
+++ b/compiler/rustc_infer/src/infer/relate/lub.rs
@@ -2,10 +2,9 @@
 
 use super::combine::{CombineFields, ObligationEmittingRelation};
 use super::lattice::{self, LatticeDir};
-use super::Subtype;
-use super::{DefineOpaqueTypes, InferCtxt};
-
+use crate::infer::{DefineOpaqueTypes, InferCtxt, SubregionOrigin};
 use crate::traits::{ObligationCause, PredicateObligations};
+
 use rustc_middle::ty::relate::{Relate, RelateResult, TypeRelation};
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
 
@@ -68,7 +67,7 @@ impl<'tcx> TypeRelation<'tcx> for Lub<'_, '_, 'tcx> {
     ) -> RelateResult<'tcx, ty::Region<'tcx>> {
         debug!("{}.regions({:?}, {:?})", self.tag(), a, b);
 
-        let origin = Subtype(Box::new(self.fields.trace.clone()));
+        let origin = SubregionOrigin::Subtype(Box::new(self.fields.trace.clone()));
         // LUB(&'static u8, &'a u8) == &RegionGLB('static, 'a) u8 == &'a u8
         Ok(self.fields.infcx.inner.borrow_mut().unwrap_region_constraints().glb_regions(
             self.tcx(),
diff --git a/compiler/rustc_infer/src/infer/relate/mod.rs b/compiler/rustc_infer/src/infer/relate/mod.rs
new file mode 100644
index 00000000000..e431734996f
--- /dev/null
+++ b/compiler/rustc_infer/src/infer/relate/mod.rs
@@ -0,0 +1,11 @@
+//! This module contains the definitions of most `TypeRelation`s in the type system
+//! (except for the NLL `TypeRelating`, and some relations used for diagnostics
+//! and heuristics in the compiler).
+
+pub(super) mod combine;
+pub(super) mod equate;
+pub(super) mod generalize;
+pub(super) mod glb;
+pub(super) mod lattice;
+pub(super) mod lub;
+pub(super) mod sub;
diff --git a/compiler/rustc_infer/src/infer/sub.rs b/compiler/rustc_infer/src/infer/relate/sub.rs
index 0c3bb633b53..5a623e48c93 100644
--- a/compiler/rustc_infer/src/infer/sub.rs
+++ b/compiler/rustc_infer/src/infer/relate/sub.rs
@@ -1,7 +1,7 @@
 use super::combine::CombineFields;
-use super::{DefineOpaqueTypes, ObligationEmittingRelation, SubregionOrigin};
-
+use crate::infer::{DefineOpaqueTypes, ObligationEmittingRelation, SubregionOrigin};
 use crate::traits::{Obligation, PredicateObligations};
+
 use rustc_middle::ty::relate::{Cause, Relate, RelateResult, TypeRelation};
 use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::TyVar;