Fix bugs in evaluating WellFormed predicates

- List the nestsed obligations in an order that works with the
  single pass used by evaluation
- Propagate recursion depth correctly

compiler/rustc_traits/src/implied_outlives_bounds.rs

@@ -61,8 +61,8 @@ fn compute_implied_outlives_bounds<'tcx>(
         // than the ultimate set. (Note: normally there won't be
         // unresolved inference variables here anyway, but there might be
         // during typeck under some circumstances.)
-        let obligations =
-            wf::obligations(infcx, param_env, hir::CRATE_HIR_ID, arg, DUMMY_SP).unwrap_or(vec![]);
+        let obligations = wf::obligations(infcx, param_env, hir::CRATE_HIR_ID, 0, arg, DUMMY_SP)
+            .unwrap_or(vec![]);
 
         // N.B., all of these predicates *ought* to be easily proven
         // true. In fact, their correctness is (mostly) implied by