Crater rollup

compiler/rustc_borrowck/src/consumers.rs

@@ -4,7 +4,6 @@ use rustc_hir::def_id::LocalDefId;
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::mir::{Body, Promoted};
-use rustc_middle::traits::DefiningAnchor;
 use rustc_middle::ty::TyCtxt;
 use std::rc::Rc;
 
@@ -106,7 +105,7 @@ pub fn get_body_with_borrowck_facts(
     options: ConsumerOptions,
 ) -> BodyWithBorrowckFacts<'_> {
     let (input_body, promoted) = tcx.mir_promoted(def);
-    let infcx = tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::bind(tcx, def)).build();
+    let infcx = tcx.infer_ctxt().with_opaque_type_inference(def).build();
     let input_body: &Body<'_> = &input_body.borrow();
     let promoted: &IndexSlice<_, _> = &promoted.borrow();
     *super::do_mir_borrowck(&infcx, input_body, promoted, Some(options)).1.unwrap()

compiler/rustc_borrowck/src/lib.rs

@@ -32,7 +32,6 @@ use rustc_infer::infer::{
 use rustc_middle::mir::tcx::PlaceTy;
 use rustc_middle::mir::*;
 use rustc_middle::query::Providers;
-use rustc_middle::traits::DefiningAnchor;
 use rustc_middle::ty::{self, ParamEnv, RegionVid, TyCtxt};
 use rustc_session::lint::builtin::UNUSED_MUT;
 use rustc_span::{Span, Symbol};
@@ -126,7 +125,7 @@ fn mir_borrowck(tcx: TyCtxt<'_>, def: LocalDefId) -> &BorrowCheckResult<'_> {
         return tcx.arena.alloc(result);
     }
 
-    let infcx = tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::bind(tcx, def)).build();
+    let infcx = tcx.infer_ctxt().with_opaque_type_inference(def).build();
     let promoted: &IndexSlice<_, _> = &promoted.borrow();
     let opt_closure_req = do_mir_borrowck(&infcx, input_body, promoted, None).0;
     debug!("mir_borrowck done");

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -7,7 +7,6 @@ use rustc_infer::infer::InferCtxt;
 use rustc_infer::infer::TyCtxtInferExt as _;
 use rustc_infer::traits::{Obligation, ObligationCause};
 use rustc_macros::extension;
-use rustc_middle::traits::DefiningAnchor;
 use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::{self, OpaqueHiddenType, OpaqueTypeKey, Ty, TyCtxt, TypeFoldable};
 use rustc_middle::ty::{GenericArgKind, GenericArgs};
@@ -146,6 +145,17 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 opaque_type_key,
                 universal_concrete_type,
             );
+
+            // Sometimes, when the hidden type is an inference variable, it can happen that
+            // the hidden type becomes the opaque type itself. In this case, this was an opaque
+            // usage of the opaque type and we can ignore it. This check is mirrored in typeck's
+            // writeback.
+            if let ty::Alias(ty::Opaque, alias_ty) = universal_concrete_type.ty.kind()
+                && alias_ty.def_id == opaque_type_key.def_id.to_def_id()
+                && alias_ty.args == opaque_type_key.args
+            {
+                continue;
+            }
             // Sometimes two opaque types are the same only after we remap the generic parameters
             // back to the opaque type definition. E.g. we may have `OpaqueType<X, Y>` mapped to `(X, Y)`
             // and `OpaqueType<Y, X>` mapped to `(Y, X)`, and those are the same, but we only know that
@@ -311,13 +321,13 @@ fn check_opaque_type_well_formed<'tcx>(
         parent_def_id = tcx.local_parent(parent_def_id);
     }
 
-    // FIXME(-Znext-solver): We probably should use `DefiningAnchor::Bind(&[])`
+    // FIXME(-Znext-solver): We probably should use `&[]` instead of
     // and prepopulate this `InferCtxt` with known opaque values, rather than
-    // using the `Bind` anchor here. For now it's fine.
+    // allowing opaque types to be defined and checking them after the fact.
     let infcx = tcx
         .infer_ctxt()
         .with_next_trait_solver(next_trait_solver)
-        .with_opaque_type_inference(DefiningAnchor::bind(tcx, parent_def_id))
+        .with_opaque_type_inference(parent_def_id)
         .build();
     let ocx = ObligationCtxt::new(&infcx);
     let identity_args = GenericArgs::identity_for_item(tcx, def_id);

compiler/rustc_errors/src/diagnostic.rs

@@ -189,7 +189,8 @@ where
     );
 }
 
-pub trait SubdiagMessageOp<G> = Fn(&mut Diag<'_, G>, SubdiagMessage) -> SubdiagMessage;
+pub trait SubdiagMessageOp<G: EmissionGuarantee> =
+    Fn(&mut Diag<'_, G>, SubdiagMessage) -> SubdiagMessage;
 
 /// Trait implemented by lint types. This should not be implemented manually. Instead, use
 /// `#[derive(LintDiagnostic)]` -- see [rustc_macros::LintDiagnostic].

compiler/rustc_hir_analysis/src/check/check.rs

@@ -13,7 +13,7 @@ use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
 use rustc_infer::traits::{Obligation, TraitEngineExt as _};
 use rustc_lint_defs::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS;
 use rustc_middle::middle::stability::EvalResult;
-use rustc_middle::traits::{DefiningAnchor, ObligationCauseCode};
+use rustc_middle::traits::ObligationCauseCode;
 use rustc_middle::ty::fold::BottomUpFolder;
 use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES};
 use rustc_middle::ty::util::{Discr, InspectCoroutineFields, IntTypeExt};
@@ -345,10 +345,7 @@ fn check_opaque_meets_bounds<'tcx>(
     };
     let param_env = tcx.param_env(defining_use_anchor);
 
-    let infcx = tcx
-        .infer_ctxt()
-        .with_opaque_type_inference(DefiningAnchor::bind(tcx, defining_use_anchor))
-        .build();
+    let infcx = tcx.infer_ctxt().with_opaque_type_inference(defining_use_anchor).build();
     let ocx = ObligationCtxt::new(&infcx);
 
     let args = match *origin {
@@ -1564,7 +1561,7 @@ pub(super) fn check_coroutine_obligations(
         .ignoring_regions()
         // Bind opaque types to type checking root, as they should have been checked by borrowck,
         // but may show up in some cases, like when (root) obligations are stalled in the new solver.
-        .with_opaque_type_inference(DefiningAnchor::bind(tcx, typeck.hir_owner.def_id))
+        .with_opaque_type_inference(typeck.hir_owner.def_id)
         .build();
 
     let mut fulfillment_cx = <dyn TraitEngine<'_>>::new(&infcx);

compiler/rustc_hir_typeck/src/demand.rs

@@ -894,7 +894,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             [candidate] => format!(
                 "the method of the same name on {} `{}`",
                 match candidate.kind {
-                    probe::CandidateKind::InherentImplCandidate(..) => "the inherent impl for",
+                    probe::CandidateKind::InherentImplCandidate(_) => "the inherent impl for",
                     _ => "trait",
                 },
                 self.tcx.def_path_str(candidate.item.container_id(self.tcx))

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -719,8 +719,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             for ty in ret_ty.walk() {
                 if let ty::GenericArgKind::Type(ty) = ty.unpack()
                     && let ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) = *ty.kind()
-                    && let Some(def_id) = def_id.as_local()
-                    && self.opaque_type_origin(def_id).is_some()
+                    && self.can_define_opaque_ty(def_id)
                 {
                     return None;
                 }

compiler/rustc_hir_typeck/src/inherited.rs

@@ -5,7 +5,6 @@ use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::HirIdMap;
 use rustc_infer::infer::{InferCtxt, InferOk, TyCtxtInferExt};
-use rustc_middle::traits::DefiningAnchor;
 use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::def_id::LocalDefIdMap;
@@ -76,11 +75,7 @@ impl<'tcx> Inherited<'tcx> {
     pub fn new(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Self {
         let hir_owner = tcx.local_def_id_to_hir_id(def_id).owner;
 
-        let infcx = tcx
-            .infer_ctxt()
-            .ignoring_regions()
-            .with_opaque_type_inference(DefiningAnchor::bind(tcx, def_id))
-            .build();
+        let infcx = tcx.infer_ctxt().ignoring_regions().with_opaque_type_inference(def_id).build();
         let typeck_results = RefCell::new(ty::TypeckResults::new(hir_owner));
 
         Inherited {