Rollup of 7 pull requests

Cargo.lock

@@ -4201,6 +4201,7 @@ dependencies = [
  "rustc_middle",
  "rustc_span",
  "rustc_target",
+ "rustc_type_ir",
  "smallvec",
  "tracing",
 ]
@@ -4392,7 +4393,6 @@ dependencies = [
  "rustc_hir_pretty",
  "rustc_index",
  "rustc_macros",
- "rustc_next_trait_solver",
  "rustc_query_system",
  "rustc_serialize",
  "rustc_session",
@@ -4509,6 +4509,7 @@ dependencies = [
  "rustc_serialize",
  "rustc_type_ir",
  "rustc_type_ir_macros",
+ "tracing",
 ]
 
 [[package]]

compiler/rustc_borrowck/src/constraints/mod.rs

@@ -1,7 +1,7 @@
 use rustc_data_structures::graph::scc::Sccs;
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_middle::mir::ConstraintCategory;
-use rustc_middle::ty::{RegionVid, VarianceDiagInfo};
+use rustc_middle::ty::{RegionVid, TyCtxt, VarianceDiagInfo};
 use rustc_span::Span;
 use std::fmt;
 use std::ops::Index;
@@ -97,7 +97,7 @@ pub struct OutlivesConstraint<'tcx> {
     pub category: ConstraintCategory<'tcx>,
 
     /// Variance diagnostic information
-    pub variance_info: VarianceDiagInfo<'tcx>,
+    pub variance_info: VarianceDiagInfo<TyCtxt<'tcx>>,
 
     /// If this constraint is promoted from closure requirements.
     pub from_closure: bool,

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -2304,5 +2304,5 @@ pub struct BlameConstraint<'tcx> {
     pub category: ConstraintCategory<'tcx>,
     pub from_closure: bool,
     pub cause: ObligationCause<'tcx>,
-    pub variance_info: ty::VarianceDiagInfo<'tcx>,
+    pub variance_info: ty::VarianceDiagInfo<TyCtxt<'tcx>>,
 }

compiler/rustc_borrowck/src/type_check/relate_tys.rs

@@ -1,14 +1,14 @@
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::ErrorGuaranteed;
+use rustc_infer::infer::relate::{ObligationEmittingRelation, StructurallyRelateAliases};
+use rustc_infer::infer::relate::{Relate, RelateResult, TypeRelation};
 use rustc_infer::infer::NllRegionVariableOrigin;
-use rustc_infer::infer::{ObligationEmittingRelation, StructurallyRelateAliases};
 use rustc_infer::traits::{Obligation, PredicateObligations};
 use rustc_middle::mir::ConstraintCategory;
 use rustc_middle::span_bug;
 use rustc_middle::traits::query::NoSolution;
 use rustc_middle::traits::ObligationCause;
 use rustc_middle::ty::fold::FnMutDelegate;
-use rustc_middle::ty::relate::{Relate, RelateResult, TypeRelation};
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
 use rustc_span::symbol::sym;
 use rustc_span::{Span, Symbol};
@@ -82,7 +82,7 @@ pub struct NllTypeRelating<'me, 'bccx, 'tcx> {
     /// - Bivariant means that it doesn't matter.
     ambient_variance: ty::Variance,
 
-    ambient_variance_info: ty::VarianceDiagInfo<'tcx>,
+    ambient_variance_info: ty::VarianceDiagInfo<TyCtxt<'tcx>>,
 }
 
 impl<'me, 'bccx, 'tcx> NllTypeRelating<'me, 'bccx, 'tcx> {
@@ -296,7 +296,7 @@ impl<'me, 'bccx, 'tcx> NllTypeRelating<'me, 'bccx, 'tcx> {
         &mut self,
         sup: ty::Region<'tcx>,
         sub: ty::Region<'tcx>,
-        info: ty::VarianceDiagInfo<'tcx>,
+        info: ty::VarianceDiagInfo<TyCtxt<'tcx>>,
     ) {
         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);
@@ -314,7 +314,7 @@ impl<'me, 'bccx, 'tcx> NllTypeRelating<'me, 'bccx, 'tcx> {
     }
 }
 
-impl<'bccx, 'tcx> TypeRelation<'tcx> for NllTypeRelating<'_, 'bccx, 'tcx> {
+impl<'bccx, 'tcx> TypeRelation<TyCtxt<'tcx>> for NllTypeRelating<'_, 'bccx, 'tcx> {
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.type_checker.infcx.tcx
     }
@@ -324,10 +324,10 @@ impl<'bccx, 'tcx> TypeRelation<'tcx> for NllTypeRelating<'_, 'bccx, 'tcx> {
     }
 
     #[instrument(skip(self, info), level = "trace", ret)]
-    fn relate_with_variance<T: Relate<'tcx>>(
+    fn relate_with_variance<T: Relate<TyCtxt<'tcx>>>(
         &mut self,
         variance: ty::Variance,
-        info: ty::VarianceDiagInfo<'tcx>,
+        info: ty::VarianceDiagInfo<TyCtxt<'tcx>>,
         a: T,
         b: T,
     ) -> RelateResult<'tcx, T> {
@@ -445,7 +445,7 @@ impl<'bccx, 'tcx> TypeRelation<'tcx> for NllTypeRelating<'_, 'bccx, 'tcx> {
         b: ty::Binder<'tcx, T>,
     ) -> RelateResult<'tcx, ty::Binder<'tcx, T>>
     where
-        T: Relate<'tcx>,
+        T: Relate<TyCtxt<'tcx>>,
     {
         // We want that
         //

compiler/rustc_hir/src/hir.rs

@@ -2345,7 +2345,9 @@ impl ImplItemId {
     }
 }
 
-/// Represents anything within an `impl` block.
+/// Represents an associated item within an impl block.
+///
+/// Refer to [`Impl`] for an impl block declaration.
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub struct ImplItem<'hir> {
     pub ident: Ident,
@@ -3327,6 +3329,10 @@ pub enum ItemKind<'hir> {
     Impl(&'hir Impl<'hir>),
 }
 
+/// Represents an impl block declaration.
+///
+/// E.g., `impl $Type { .. }` or `impl $Trait for $Type { .. }`
+/// Refer to [`ImplItem`] for an associated item within an impl block.
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub struct Impl<'hir> {
     pub safety: Safety,

compiler/rustc_hir_analysis/src/check/check.rs

@@ -15,6 +15,7 @@ use rustc_lint_defs::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS;
 use rustc_middle::middle::resolve_bound_vars::ResolvedArg;
 use rustc_middle::middle::stability::EvalResult;
 use rustc_middle::span_bug;
+use rustc_middle::ty::error::TypeErrorToStringExt;
 use rustc_middle::ty::fold::BottomUpFolder;
 use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES};
 use rustc_middle::ty::util::{Discr, InspectCoroutineFields, IntTypeExt};

compiler/rustc_hir_typeck/src/coercion.rs

@@ -41,6 +41,7 @@ use rustc_errors::{codes::*, struct_span_code_err, Applicability, Diag};
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir_analysis::hir_ty_lowering::HirTyLowerer;
+use rustc_infer::infer::relate::RelateResult;
 use rustc_infer::infer::{Coercion, DefineOpaqueTypes, InferOk, InferResult};
 use rustc_infer::traits::{IfExpressionCause, MatchExpressionArmCause};
 use rustc_infer::traits::{Obligation, PredicateObligation};
@@ -51,7 +52,6 @@ use rustc_middle::ty::adjustment::{
     Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, PointerCoercion,
 };
 use rustc_middle::ty::error::TypeError;
-use rustc_middle::ty::relate::RelateResult;
 use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::{self, GenericArgsRef, Ty, TyCtxt};
 use rustc_session::parse::feature_err;

compiler/rustc_hir_typeck/src/expr.rs

@@ -40,7 +40,7 @@ use rustc_infer::infer::InferOk;
 use rustc_infer::traits::query::NoSolution;
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase};
-use rustc_middle::ty::error::{ExpectedFound, TypeError::Sorts};
+use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::GenericArgsRef;
 use rustc_middle::ty::{self, AdtKind, Ty, TypeVisitableExt};
 use rustc_middle::{bug, span_bug};
@@ -682,7 +682,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             self.suggest_mismatched_types_on_tail(
                                 &mut err, expr, ty, e_ty, target_id,
                             );
-                            let error = Some(Sorts(ExpectedFound { expected: ty, found: e_ty }));
+                            let error =
+                                Some(TypeError::Sorts(ExpectedFound { expected: ty, found: e_ty }));
                             self.annotate_loop_expected_due_to_inference(err, expr, error);
                             if let Some(val) =
                                 self.err_ctxt().ty_kind_suggestion(self.param_env, ty)

compiler/rustc_infer/Cargo.toml

@@ -18,6 +18,7 @@ rustc_macros = { path = "../rustc_macros" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_span = { path = "../rustc_span" }
 rustc_target = { path = "../rustc_target" }
+rustc_type_ir = { path = "../rustc_type_ir" }
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
 tracing = "0.1"
 # tidy-alphabetical-end

compiler/rustc_infer/src/infer/at.rs

@@ -27,8 +27,8 @@
 
 use super::*;
 
+use crate::infer::relate::{Relate, StructurallyRelateAliases, TypeRelation};
 use rustc_middle::bug;
-use rustc_middle::ty::relate::{Relate, TypeRelation};
 use rustc_middle::ty::{Const, ImplSubject};
 
 /// Whether we should define opaque types or just treat them opaquely.
@@ -90,7 +90,7 @@ impl<'tcx> InferCtxt<'tcx> {
     }
 }
 
-pub trait ToTrace<'tcx>: Relate<'tcx> + Copy {
+pub trait ToTrace<'tcx>: Relate<TyCtxt<'tcx>> + Copy {
     fn to_trace(
         cause: &ObligationCause<'tcx>,
         a_is_expected: bool,

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -58,6 +58,7 @@ use crate::traits::{
     PredicateObligation,
 };
 
+use crate::infer::relate::{self, RelateResult, TypeRelation};
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_errors::{
     codes::*, pluralize, struct_span_code_err, Applicability, Diag, DiagCtxt, DiagStyledString,
@@ -71,8 +72,8 @@ use rustc_hir::lang_items::LangItem;
 use rustc_macros::extension;
 use rustc_middle::bug;
 use rustc_middle::dep_graph::DepContext;
+use rustc_middle::ty::error::TypeErrorToStringExt;
 use rustc_middle::ty::print::{with_forced_trimmed_paths, PrintError, PrintTraitRefExt as _};
-use rustc_middle::ty::relate::{self, RelateResult, TypeRelation};
 use rustc_middle::ty::Upcast;
 use rustc_middle::ty::{
     self, error::TypeError, IsSuggestable, List, Region, Ty, TyCtxt, TypeFoldable,
@@ -2686,15 +2687,15 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
     /// with the other type. A TyVar inference type is compatible with any type, and an IntVar or
     /// FloatVar inference type are compatible with themselves or their concrete types (Int and
     /// Float types, respectively). When comparing two ADTs, these rules apply recursively.
-    pub fn same_type_modulo_infer<T: relate::Relate<'tcx>>(&self, a: T, b: T) -> bool {
+    pub fn same_type_modulo_infer<T: relate::Relate<TyCtxt<'tcx>>>(&self, a: T, b: T) -> bool {
         let (a, b) = self.resolve_vars_if_possible((a, b));
         SameTypeModuloInfer(self).relate(a, b).is_ok()
     }
 }
 
 struct SameTypeModuloInfer<'a, 'tcx>(&'a InferCtxt<'tcx>);
 
-impl<'tcx> TypeRelation<'tcx> for SameTypeModuloInfer<'_, 'tcx> {
+impl<'tcx> TypeRelation<TyCtxt<'tcx>> for SameTypeModuloInfer<'_, 'tcx> {
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.0.tcx
     }
@@ -2703,10 +2704,10 @@ impl<'tcx> TypeRelation<'tcx> for SameTypeModuloInfer<'_, 'tcx> {
         "SameTypeModuloInfer"
     }
 
-    fn relate_with_variance<T: relate::Relate<'tcx>>(
+    fn relate_with_variance<T: relate::Relate<TyCtxt<'tcx>>>(
         &mut self,
         _variance: ty::Variance,
-        _info: ty::VarianceDiagInfo<'tcx>,
+        _info: ty::VarianceDiagInfo<TyCtxt<'tcx>>,
         a: T,
         b: T,
     ) -> relate::RelateResult<'tcx, T> {
@@ -2754,7 +2755,7 @@ impl<'tcx> TypeRelation<'tcx> for SameTypeModuloInfer<'_, 'tcx> {
         b: ty::Binder<'tcx, T>,
     ) -> relate::RelateResult<'tcx, ty::Binder<'tcx, T>>
     where
-        T: relate::Relate<'tcx>,
+        T: relate::Relate<TyCtxt<'tcx>>,
     {
         Ok(a.rebind(self.relate(a.skip_binder(), b.skip_binder())?))
     }

compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs

@@ -21,13 +21,12 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         sp: Span,
         body_owner_def_id: DefId,
     ) {
-        use ty::error::TypeError::*;
         debug!("note_and_explain_type_err err={:?} cause={:?}", err, cause);
 
         let tcx = self.tcx;
 
         match err {
-            ArgumentSorts(values, _) | Sorts(values) => {
+            TypeError::ArgumentSorts(values, _) | TypeError::Sorts(values) => {
                 match (*values.expected.kind(), *values.found.kind()) {
                     (ty::Closure(..), ty::Closure(..)) => {
                         diag.note("no two closures, even if identical, have the same type");
@@ -483,7 +482,7 @@ impl<T> Trait<T> for X {
                     values.found.kind(),
                 );
             }
-            CyclicTy(ty) => {
+            TypeError::CyclicTy(ty) => {
                 // Watch out for various cases of cyclic types and try to explain.
                 if ty.is_closure() || ty.is_coroutine() || ty.is_coroutine_closure() {
                     diag.note(
@@ -494,7 +493,7 @@ impl<T> Trait<T> for X {
                     );
                 }
             }
-            TargetFeatureCast(def_id) => {
+            TypeError::TargetFeatureCast(def_id) => {
                 let target_spans = tcx.get_attrs(def_id, sym::target_feature).map(|attr| attr.span);
                 diag.note(
                     "functions with `#[target_feature]` can only be coerced to `unsafe` function pointers"

compiler/rustc_infer/src/infer/mod.rs

@@ -1,16 +1,14 @@
 pub use at::DefineOpaqueTypes;
 pub use freshen::TypeFreshener;
 pub use lexical_region_resolve::RegionResolutionError;
-pub use relate::combine::CombineFields;
-pub use relate::combine::ObligationEmittingRelation;
-pub use relate::StructurallyRelateAliases;
 pub use rustc_macros::{TypeFoldable, TypeVisitable};
 pub use rustc_middle::ty::IntVarValue;
 pub use BoundRegionConversionTime::*;
 pub use RegionVariableOrigin::*;
 pub use SubregionOrigin::*;
 pub use ValuePairs::*;
 
+use crate::infer::relate::{CombineFields, RelateResult};
 use crate::traits::{
     self, ObligationCause, ObligationInspector, PredicateObligations, TraitEngine,
 };
@@ -39,7 +37,6 @@ use rustc_middle::traits::select;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::fold::BoundVarReplacerDelegate;
 use rustc_middle::ty::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
-use rustc_middle::ty::relate::RelateResult;
 use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::{self, GenericParamDefKind, InferConst, Ty, TyCtxt};
 use rustc_middle::ty::{ConstVid, EffectVid, FloatVid, IntVid, TyVid};
@@ -62,7 +59,7 @@ pub mod opaque_types;
 pub mod outlives;
 mod projection;
 pub mod region_constraints;
-mod relate;
+pub mod relate;
 pub mod resolve;
 pub(crate) mod snapshot;
 pub mod type_variable;

compiler/rustc_infer/src/infer/outlives/test_type_match.rs

@@ -1,15 +1,12 @@
 use std::collections::hash_map::Entry;
 
 use rustc_data_structures::fx::FxHashMap;
+use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::TypeVisitableExt;
-use rustc_middle::ty::{
-    self,
-    error::TypeError,
-    relate::{self, Relate, RelateResult, TypeRelation},
-    Ty, TyCtxt,
-};
+use rustc_middle::ty::{self, Ty, TyCtxt};
 
 use crate::infer::region_constraints::VerifyIfEq;
+use crate::infer::relate::{self as relate, Relate, RelateResult, TypeRelation};
 
 /// Given a "verify-if-eq" type test like:
 ///
@@ -135,7 +132,7 @@ impl<'tcx> MatchAgainstHigherRankedOutlives<'tcx> {
     }
 }
 
-impl<'tcx> TypeRelation<'tcx> for MatchAgainstHigherRankedOutlives<'tcx> {
+impl<'tcx> TypeRelation<TyCtxt<'tcx>> for MatchAgainstHigherRankedOutlives<'tcx> {
     fn tag(&self) -> &'static str {
         "MatchAgainstHigherRankedOutlives"
     }
@@ -145,10 +142,10 @@ impl<'tcx> TypeRelation<'tcx> for MatchAgainstHigherRankedOutlives<'tcx> {
     }
 
     #[instrument(level = "trace", skip(self))]
-    fn relate_with_variance<T: Relate<'tcx>>(
+    fn relate_with_variance<T: Relate<TyCtxt<'tcx>>>(
         &mut self,
         variance: ty::Variance,
-        _: ty::VarianceDiagInfo<'tcx>,
+        _: ty::VarianceDiagInfo<TyCtxt<'tcx>>,
         a: T,
         b: T,
     ) -> RelateResult<'tcx, T> {
@@ -208,7 +205,7 @@ impl<'tcx> TypeRelation<'tcx> for MatchAgainstHigherRankedOutlives<'tcx> {
         value: ty::Binder<'tcx, T>,
     ) -> RelateResult<'tcx, ty::Binder<'tcx, T>>
     where
-        T: Relate<'tcx>,
+        T: Relate<TyCtxt<'tcx>>,
     {
         self.pattern_depth.shift_in(1);
         let result = Ok(pattern.rebind(self.relate(pattern.skip_binder(), value.skip_binder())?));