Migrate item_bounds to ty::Clause

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -409,9 +409,7 @@ fn fn_sig_suggestion<'tcx>(
         output = if let ty::Alias(_, alias_ty) = *output.kind() {
             tcx.explicit_item_bounds(alias_ty.def_id)
                 .subst_iter_copied(tcx, alias_ty.substs)
-                .find_map(|(bound, _)| {
-                    bound.to_opt_poly_projection_pred()?.no_bound_vars()?.term.ty()
-                })
+                .find_map(|(bound, _)| bound.as_projection_clause()?.no_bound_vars()?.term.ty())
                 .unwrap_or_else(|| {
                     span_bug!(
                         ident.span,

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -1086,7 +1086,7 @@ fn check_associated_type_bounds(wfcx: &WfCheckingCtxt<'_, '_>, item: ty::AssocIt
             wfcx.infcx,
             wfcx.param_env,
             wfcx.body_def_id,
-            normalized_bound,
+            normalized_bound.as_predicate(),
             bound_span,
         )
     });
@@ -1562,7 +1562,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ImplTraitInTraitFinder<'_, 'tcx> {
                     self.wfcx.infcx,
                     self.wfcx.param_env,
                     self.wfcx.body_def_id,
-                    bound,
+                    bound.as_predicate(),
                     bound_span,
                 ));
                 // Set the debruijn index back to innermost here, since we already eagerly