Liberate before normalizing in wfcheck

Author: jackh726

compiler/rustc_typeck/src/check/wfcheck.rs

@@ -406,7 +406,6 @@ fn check_associated_item(
             }
             ty::AssocKind::Fn => {
                 let sig = fcx.tcx.fn_sig(item.def_id);
-                let sig = fcx.normalize_associated_types_in(span, sig);
                 let hir_sig = sig_if_method.expect("bad signature for method");
                 check_fn_or_method(
                     fcx,
@@ -611,7 +610,6 @@ fn check_item_fn(
     for_id(tcx, item_id, span).with_fcx(|fcx| {
         let def_id = tcx.hir().local_def_id(item_id);
         let sig = tcx.fn_sig(def_id);
-        let sig = fcx.normalize_associated_types_in(span, sig);
         let mut implied_bounds = vec![];
         check_fn_or_method(fcx, ident.span, sig, decl, def_id.to_def_id(), &mut implied_bounds);
         implied_bounds
@@ -902,8 +900,8 @@ fn check_fn_or_method<'fcx, 'tcx>(
     def_id: DefId,
     implied_bounds: &mut Vec<Ty<'tcx>>,
 ) {
-    let sig = fcx.normalize_associated_types_in(span, sig);
     let sig = fcx.tcx.liberate_late_bound_regions(def_id, sig);
+    let sig = fcx.normalize_associated_types_in(span, sig);
 
     for (&input_ty, ty) in iter::zip(sig.inputs(), hir_decl.inputs) {
         fcx.register_wf_obligation(input_ty.into(), ty.span, ObligationCauseCode::MiscObligation);
@@ -1081,8 +1079,8 @@ fn check_method_receiver<'fcx, 'tcx>(
     let span = fn_sig.decl.inputs[0].span;
 
     let sig = fcx.tcx.fn_sig(method.def_id);
-    let sig = fcx.normalize_associated_types_in(span, sig);
     let sig = fcx.tcx.liberate_late_bound_regions(method.def_id, sig);
+    let sig = fcx.normalize_associated_types_in(span, sig);
 
     debug!("check_method_receiver: sig={:?}", sig);