Get rid of PredicateObligations

compiler/rustc_infer/src/infer/mod.rs

@@ -9,9 +9,7 @@ pub use SubregionOrigin::*;
 pub use ValuePairs::*;
 
 use crate::infer::relate::{CombineFields, RelateResult};
-use crate::traits::{
-    self, ObligationCause, ObligationInspector, PredicateObligations, TraitEngine,
-};
+use crate::traits::{self, ObligationCause, ObligationInspector, PredicateObligation, TraitEngine};
 use error_reporting::TypeErrCtxt;
 use free_regions::RegionRelations;
 use lexical_region_resolve::LexicalRegionResolutions;
@@ -68,7 +66,7 @@ pub mod type_variable;
 #[derive(Debug)]
 pub struct InferOk<'tcx, T> {
     pub value: T,
-    pub obligations: PredicateObligations<'tcx>,
+    pub obligations: Vec<PredicateObligation<'tcx>>,
 }
 pub type InferResult<'tcx, T> = Result<InferOk<'tcx, T>, TypeError<'tcx>>;
 
@@ -748,7 +746,7 @@ impl<'tcx, T> InferOk<'tcx, T> {
 }
 
 impl<'tcx> InferOk<'tcx, ()> {
-    pub fn into_obligations(self) -> PredicateObligations<'tcx> {
+    pub fn into_obligations(self) -> Vec<PredicateObligation<'tcx>> {
         self.obligations
     }
 }

compiler/rustc_infer/src/infer/relate/combine.rs

@@ -25,7 +25,7 @@ use super::StructurallyRelateAliases;
 use super::{RelateResult, TypeRelation};
 use crate::infer::relate;
 use crate::infer::{DefineOpaqueTypes, InferCtxt, TypeTrace};
-use crate::traits::{Obligation, PredicateObligations};
+use crate::traits::{Obligation, PredicateObligation};
 use rustc_middle::bug;
 use rustc_middle::infer::unify_key::EffectVarValue;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
@@ -38,7 +38,7 @@ pub struct CombineFields<'infcx, 'tcx> {
     pub infcx: &'infcx InferCtxt<'tcx>,
     pub trace: TypeTrace<'tcx>,
     pub param_env: ty::ParamEnv<'tcx>,
-    pub obligations: PredicateObligations<'tcx>,
+    pub obligations: Vec<PredicateObligation<'tcx>>,
     pub define_opaque_types: DefineOpaqueTypes,
 }
 
@@ -290,7 +290,7 @@ impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> {
         Glb::new(self)
     }
 
-    pub fn register_obligations(&mut self, obligations: PredicateObligations<'tcx>) {
+    pub fn register_obligations(&mut self, obligations: Vec<PredicateObligation<'tcx>>) {
         self.obligations.extend(obligations);
     }
 
@@ -315,7 +315,7 @@ pub trait ObligationEmittingRelation<'tcx>: TypeRelation<TyCtxt<'tcx>> {
     fn structurally_relate_aliases(&self) -> StructurallyRelateAliases;
 
     /// Register obligations that must hold in order for this relation to hold
-    fn register_obligations(&mut self, obligations: PredicateObligations<'tcx>);
+    fn register_obligations(&mut self, obligations: Vec<PredicateObligation<'tcx>>);
 
     /// Register predicates that must hold in order for this relation to hold. Uses
     /// a default obligation cause, [`ObligationEmittingRelation::register_obligations`] should

compiler/rustc_infer/src/infer/relate/glb.rs

@@ -8,7 +8,7 @@ use super::combine::{CombineFields, ObligationEmittingRelation};
 use super::lattice::{self, LatticeDir};
 use super::StructurallyRelateAliases;
 use crate::infer::{DefineOpaqueTypes, InferCtxt, SubregionOrigin};
-use crate::traits::{ObligationCause, PredicateObligations};
+use crate::traits::{ObligationCause, PredicateObligation};
 
 /// "Greatest lower bound" (common subtype)
 pub struct Glb<'combine, 'infcx, 'tcx> {
@@ -147,7 +147,7 @@ impl<'tcx> ObligationEmittingRelation<'tcx> for Glb<'_, '_, 'tcx> {
         self.fields.register_predicates(obligations);
     }
 
-    fn register_obligations(&mut self, obligations: PredicateObligations<'tcx>) {
+    fn register_obligations(&mut self, obligations: Vec<PredicateObligation<'tcx>>) {
         self.fields.register_obligations(obligations);
     }
 

compiler/rustc_infer/src/infer/relate/lub.rs

@@ -4,7 +4,7 @@ use super::combine::{CombineFields, ObligationEmittingRelation};
 use super::lattice::{self, LatticeDir};
 use super::StructurallyRelateAliases;
 use crate::infer::{DefineOpaqueTypes, InferCtxt, SubregionOrigin};
-use crate::traits::{ObligationCause, PredicateObligations};
+use crate::traits::{ObligationCause, PredicateObligation};
 
 use super::{Relate, RelateResult, TypeRelation};
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
@@ -147,7 +147,7 @@ impl<'tcx> ObligationEmittingRelation<'tcx> for Lub<'_, '_, 'tcx> {
         self.fields.register_predicates(obligations);
     }
 
-    fn register_obligations(&mut self, obligations: PredicateObligations<'tcx>) {
+    fn register_obligations(&mut self, obligations: Vec<PredicateObligation<'tcx>>) {
         self.fields.register_obligations(obligations)
     }
 

compiler/rustc_infer/src/infer/relate/type_relating.rs

@@ -1,7 +1,7 @@
 use super::combine::CombineFields;
 use crate::infer::BoundRegionConversionTime::HigherRankedType;
 use crate::infer::{DefineOpaqueTypes, SubregionOrigin};
-use crate::traits::{Obligation, PredicateObligations};
+use crate::traits::{Obligation, PredicateObligation};
 
 use super::{
     relate_args_invariantly, relate_args_with_variances, ObligationEmittingRelation, Relate,
@@ -318,7 +318,7 @@ impl<'tcx> ObligationEmittingRelation<'tcx> for TypeRelating<'_, '_, 'tcx> {
         self.fields.register_predicates(obligations);
     }
 
-    fn register_obligations(&mut self, obligations: PredicateObligations<'tcx>) {
+    fn register_obligations(&mut self, obligations: Vec<PredicateObligation<'tcx>>) {
         self.fields.register_obligations(obligations);
     }
 

compiler/rustc_infer/src/traits/mod.rs

@@ -114,8 +114,6 @@ impl<'tcx> PolyTraitObligation<'tcx> {
 #[cfg(target_pointer_width = "64")]
 rustc_data_structures::static_assert_size!(PredicateObligation<'_>, 48);
 
-pub type PredicateObligations<'tcx> = Vec<PredicateObligation<'tcx>>;
-
 pub type Selection<'tcx> = ImplSource<'tcx, PredicateObligation<'tcx>>;
 
 /// A callback that can be provided to `inspect_typeck`. Invoked on evaluation