inspect_obligations cleanup

Author: lcnr

compiler/rustc_hir_typeck/src/fn_ctxt/inspect_obligations.rs

@@ -1,3 +1,4 @@
+use crate::rustc_middle::ty::TypeVisitableExt;
 use crate::FnCtxt;
 use rustc_infer::traits::solve::Goal;
 use rustc_infer::traits::{self, ObligationCause};
@@ -31,10 +32,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     ) -> bool {
         match predicate.kind().skip_binder() {
             ty::PredicateKind::Clause(ty::ClauseKind::Trait(data)) => {
-                self.self_type_matches_expected_vid(data.self_ty(), expected_vid)
+                self.type_matches_expected_vid(expected_vid, data.self_ty())
             }
             ty::PredicateKind::Clause(ty::ClauseKind::Projection(data)) => {
-                self.self_type_matches_expected_vid(data.projection_ty.self_ty(), expected_vid)
+                self.type_matches_expected_vid(expected_vid, data.projection_ty.self_ty())
             }
             ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(..))
             | ty::PredicateKind::Subtype(..)
@@ -52,11 +53,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 
     #[instrument(level = "debug", skip(self), ret)]
-    fn self_type_matches_expected_vid(&self, self_ty: Ty<'tcx>, expected_vid: ty::TyVid) -> bool {
-        let self_ty = self.shallow_resolve(self_ty);
-        debug!(?self_ty);
+    fn type_matches_expected_vid(&self, expected_vid: ty::TyVid, ty: Ty<'tcx>) -> bool {
+        let ty = self.shallow_resolve(ty);
+        debug!(?ty);
 
-        match *self_ty.kind() {
+        match *ty.kind() {
             ty::Infer(ty::TyVar(found_vid)) => expected_vid == self.root_var(found_vid),
             _ => false,
         }
@@ -67,6 +68,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self_ty: ty::TyVid,
     ) -> Vec<traits::PredicateObligation<'tcx>> {
         let obligations = self.fulfillment_cx.borrow().pending_obligations();
+        debug!(?obligations);
         let mut obligations_for_self_ty = vec![];
         for obligation in obligations {
             let mut visitor = NestedObligationsForSelfTy {
@@ -79,6 +81,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let goal = Goal::new(self.tcx, obligation.param_env, obligation.predicate);
             self.visit_proof_tree(goal, &mut visitor);
         }
+
+        obligations_for_self_ty.retain_mut(|obligation| {
+            obligation.predicate = self.resolve_vars_if_possible(obligation.predicate);
+            !obligation.predicate.has_placeholders()
+        });
         obligations_for_self_ty
     }
 }