Slightly improve mismatched GAT where clause error

[rust.git] / compiler / rustc_typeck / src / check / compare_method.rs

diff --git a/compiler/rustc_typeck/src/check/compare_method.rs b/compiler/rustc_typeck/src/check/compare_method.rs
index 6ae17fc61762fbcfcf064a7dd33eeaee56dfc57c..91364ac35cb111163259da382eccde2392a8ee2b 100644 (file)
--- a/compiler/rustc_typeck/src/check/compare_method.rs
+++ b/compiler/rustc_typeck/src/check/compare_method.rs
@@ -2,7 +2,7 @@
 use crate::check::regionck::OutlivesEnvironmentExt;
 use crate::check::wfcheck;
 use crate::errors::LifetimesOrBoundsMismatchOnTrait;
-use rustc_data_structures::stable_set::FxHashSet;
+use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticId, ErrorGuaranteed};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
@@ -1212,15 +1212,6 @@ fn compare_type_predicate_entailment<'tcx>(
     // `ObligationCause` (and the `FnCtxt`). This is what
     // `regionck_item` expects.
     let impl_ty_hir_id = tcx.hir().local_def_id_to_hir_id(impl_ty.def_id.expect_local());
-    let cause = ObligationCause::new(
-        impl_ty_span,
-        impl_ty_hir_id,
-        ObligationCauseCode::CompareImplTypeObligation {
-            impl_item_def_id: impl_ty.def_id.expect_local(),
-            trait_item_def_id: trait_ty.def_id,
-        },
-    );
-
     debug!("compare_type_predicate_entailment: trait_to_impl_substs={:?}", trait_to_impl_substs);
 
     // The predicates declared by the impl definition, the trait and the
@@ -1239,7 +1230,7 @@ fn compare_type_predicate_entailment<'tcx>(
         Reveal::UserFacing,
         hir::Constness::NotConst,
     );
-    let param_env = traits::normalize_param_env_or_error(tcx, param_env, normalize_cause.clone());
+    let param_env = traits::normalize_param_env_or_error(tcx, param_env, normalize_cause);
     tcx.infer_ctxt().enter(|infcx| {
         let ocx = ObligationCtxt::new(&infcx);
 
@@ -1247,12 +1238,24 @@ fn compare_type_predicate_entailment<'tcx>(
 
         let mut selcx = traits::SelectionContext::new(&infcx);
 
-        for predicate in impl_ty_own_bounds.predicates {
+        assert_eq!(impl_ty_own_bounds.predicates.len(), impl_ty_own_bounds.spans.len());
+        for (span, predicate) in
+            std::iter::zip(impl_ty_own_bounds.spans, impl_ty_own_bounds.predicates)
+        {
+            let cause = ObligationCause::misc(span, impl_ty_hir_id);
             let traits::Normalized { value: predicate, obligations } =
-                traits::normalize(&mut selcx, param_env, normalize_cause.clone(), predicate);
+                traits::normalize(&mut selcx, param_env, cause, predicate);
 
+            let cause = ObligationCause::new(
+                span,
+                impl_ty_hir_id,
+                ObligationCauseCode::CompareImplTypeObligation {
+                    impl_item_def_id: impl_ty.def_id.expect_local(),
+                    trait_item_def_id: trait_ty.def_id,
+                },
+            );
             ocx.register_obligations(obligations);
-            ocx.register_obligation(traits::Obligation::new(cause.clone(), param_env, predicate));
+            ocx.register_obligation(traits::Obligation::new(cause, param_env, predicate));
         }
 
         // Check that all obligations are satisfied by the implementation's
@@ -1460,6 +1463,7 @@ pub fn check_type_bounds<'tcx>(
             .map(|e| e.map_bound(|e| *e).transpose_tuple2())
             .map(|(bound, span)| {
                 debug!(?bound);
+                // this is where opaque type is found
                 let concrete_ty_bound = bound.subst(tcx, rebased_substs);
                 debug!("check_type_bounds: concrete_ty_bound = {:?}", concrete_ty_bound);
 
@@ -1481,7 +1485,6 @@ pub fn check_type_bounds<'tcx>(
             ocx.register_obligations(obligations);
             ocx.register_obligation(obligation);
         }
-
         // Check that all obligations are satisfied by the implementation's
         // version.
         let errors = ocx.select_all_or_error();
@@ -1513,7 +1516,7 @@ pub fn check_type_bounds<'tcx>(
                         value.hidden_type.span,
                         tcx.hir().local_def_id_to_hir_id(impl_ty.def_id.expect_local()),
                     ),
-                    tcx.mk_opaque(key.def_id, key.substs),
+                    tcx.mk_opaque(key.def_id.to_def_id(), key.substs),
                     value.hidden_type.ty,
                     TypeError::Mismatch,
                 )