add FIXME to fulfill

Author: nikomatsakis

src/librustc/traits/fulfill.rs

@@ -408,6 +408,8 @@ fn process_predicate<'a, 'gcx, 'tcx>(
                     // also includes references to its upvars as part
                     // of its type, and those types are resolved at
                     // the same time.
+                    //
+                    // FIXME(#32286) logic seems false if no upvars
                     pending_obligation.stalled_on =
                         trait_ref_type_vars(selcx, data.to_poly_trait_ref());