Use Term in ProjectionPredicate

ProjectionPredicate should be able to handle both associated types and consts so this adds the
first step of that. It mainly just pipes types all the way down, not entirely sure how to handle
consts, but hopefully that'll come with time.

4 files changed, 14 insertions, 13 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
index b4d297a03ef..85135383b80 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -1304,7 +1304,8 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
 
                 debug!(
                     "report_projection_error normalized_ty={:?} data.ty={:?}",
-                    normalized_ty, data.ty
+                    normalized_ty,
+                    data.term.ty()
                 );
 
                 let is_normalized_ty_expected = !matches!(
@@ -1318,12 +1319,12 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                 if let Err(error) = self.at(&obligation.cause, obligation.param_env).eq_exp(
                     is_normalized_ty_expected,
                     normalized_ty,
-                    data.ty,
+                    data.term.ty(),
                 ) {
                     values = Some(infer::ValuePairs::Types(ExpectedFound::new(
                         is_normalized_ty_expected,
                         normalized_ty,
-                        data.ty,
+                        data.term.ty(),
                     )));
 
                     err_buf = error;
@@ -1803,7 +1804,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
             }
             ty::PredicateKind::Projection(data) => {
                 let self_ty = data.projection_ty.self_ty();
-                let ty = data.ty;
+                let ty = data.term.ty();
                 if predicate.references_error() || self.is_tainted_by_errors() {
                     return;
                 }
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index 577b96f3a40..4995590baec 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -214,7 +214,7 @@ fn project_and_unify_type<'cx, 'tcx>(
     let infcx = selcx.infcx();
     match infcx
         .at(&obligation.cause, obligation.param_env)
-        .eq(normalized_ty, obligation.predicate.ty)
+        .eq(normalized_ty, obligation.predicate.term.ty())
     {
         Ok(InferOk { obligations: inferred_obligations, value: () }) => {
             obligations.extend(inferred_obligations);
@@ -1615,7 +1615,7 @@ fn confirm_generator_candidate<'cx, 'tcx>(
                 substs: trait_ref.substs,
                 item_def_id: obligation.predicate.item_def_id,
             },
-            ty,
+            term: ty.into(),
         }
     });
 
@@ -1641,7 +1641,7 @@ fn confirm_discriminant_kind_candidate<'cx, 'tcx>(
 
     let predicate = ty::ProjectionPredicate {
         projection_ty: ty::ProjectionTy { substs, item_def_id: discriminant_def_id },
-        ty: self_ty.discriminant_ty(tcx),
+        term: self_ty.discriminant_ty(tcx).into(),
     };
 
     // We get here from `poly_project_and_unify_type` which replaces bound vars
@@ -1674,7 +1674,7 @@ fn confirm_pointee_candidate<'cx, 'tcx>(
 
     let predicate = ty::ProjectionPredicate {
         projection_ty: ty::ProjectionTy { substs, item_def_id: metadata_def_id },
-        ty: metadata_ty,
+        term: metadata_ty.into(),
     };
 
     confirm_param_env_candidate(selcx, obligation, ty::Binder::dummy(predicate), false)
@@ -1747,7 +1747,7 @@ fn confirm_callable_candidate<'cx, 'tcx>(
             substs: trait_ref.substs,
             item_def_id: fn_once_output_def_id,
         },
-        ty: ret_type,
+        term: ret_type.into(),
     });
 
     confirm_param_env_candidate(selcx, obligation, predicate, true)
@@ -1803,7 +1803,7 @@ fn confirm_param_env_candidate<'cx, 'tcx>(
         Ok(InferOk { value: _, obligations }) => {
             nested_obligations.extend(obligations);
             assoc_ty_own_obligations(selcx, obligation, &mut nested_obligations);
-            Progress { ty: cache_entry.ty, obligations: nested_obligations }
+            Progress { ty: cache_entry.term.ty(), obligations: nested_obligations }
         }
         Err(e) => {
             let msg = format!(
diff --git a/compiler/rustc_trait_selection/src/traits/relationships.rs b/compiler/rustc_trait_selection/src/traits/relationships.rs
index e0098cc92d5..acac76cdfaa 100644
--- a/compiler/rustc_trait_selection/src/traits/relationships.rs
+++ b/compiler/rustc_trait_selection/src/traits/relationships.rs
@@ -62,7 +62,7 @@ pub(crate) fn update<'tcx, T>(
     if let ty::PredicateKind::Projection(predicate) = obligation.predicate.kind().skip_binder() {
         // If the projection predicate (Foo::Bar == X) has X as a non-TyVid,
         // we need to make it into one.
-        if let Some(vid) = predicate.ty.ty_vid() {
+        if let Some(vid) = predicate.term.ty().ty_vid() {
             debug!("relationship: {:?}.output = true", vid);
             engine.relationships().entry(vid).or_default().output = true;
         }
diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs
index f6e98f42710..e3b366c65bf 100644
--- a/compiler/rustc_trait_selection/src/traits/wf.rs
+++ b/compiler/rustc_trait_selection/src/traits/wf.rs
@@ -116,7 +116,7 @@ pub fn predicate_obligations<'a, 'tcx>(
         }
         ty::PredicateKind::Projection(t) => {
             wf.compute_projection(t.projection_ty);
-            wf.compute(t.ty.into());
+            wf.compute(t.term.ty().into());
         }
         ty::PredicateKind::WellFormed(arg) => {
             wf.compute(arg);
@@ -219,7 +219,7 @@ fn extend_cause_with_original_assoc_item_obligation<'tcx>(
             // projection coming from another associated type. See
             // `src/test/ui/associated-types/point-at-type-on-obligation-failure.rs` and
             // `traits-assoc-type-in-supertrait-bad.rs`.
-            if let ty::Projection(projection_ty) = proj.ty.kind() {
+            if let ty::Projection(projection_ty) = proj.term.ty().kind() {
                 if let Some(&impl_item_id) =
                     tcx.impl_item_implementor_ids(impl_def_id).get(&projection_ty.item_def_id)
                 {