diff --git a/src/abi.rs b/src/abi.rs
index 6eae368eced..a87984d4cd9 100644
--- a/src/abi.rs
+++ b/src/abi.rs
@@ -160,11 +160,7 @@ pub fn get_function_name_and_sig<'a, 'tcx>(
     assert!(!inst.substs.needs_infer() && !inst.substs.has_param_types());
     let fn_ty = inst.ty(tcx);
     let sig = cton_sig_from_fn_ty(tcx, fn_ty);
-    let def_path_based_names =
-        ::rustc_mir::monomorphize::item::DefPathBasedNames::new(tcx, false, false);
-    let mut name = String::new();
-    def_path_based_names.push_instance_as_string(inst, &mut name);
-    (name, sig)
+    (tcx.symbol_name(inst).as_str().to_string(), sig)
 }
 
 impl<'a, 'tcx: 'a> CodegenCx<'a, 'tcx, CurrentBackend> {
diff --git a/src/base.rs b/src/base.rs
index a5d93959552..fd0268db573 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -11,7 +11,7 @@ pub fn trans_mono_item<'a, 'tcx: 'a>(
         MonoItem::Fn(inst) => match inst {
             Instance {
                 def: InstanceDef::Item(def_id),
-                substs,
+                substs: _,
             } => {
                 let mut mir = ::std::io::Cursor::new(Vec::new());
                 ::rustc_mir::util::write_mir_pretty(tcx, Some(def_id), &mut mir).unwrap();
@@ -21,13 +21,6 @@ pub fn trans_mono_item<'a, 'tcx: 'a>(
                     String::from_utf8_lossy(&mir.into_inner())
                 ));
 
-                let fn_ty = inst.ty(tcx);
-                let fn_ty = tcx.subst_and_normalize_erasing_regions(
-                    substs,
-                    ty::ParamEnv::reveal_all(),
-                    &fn_ty,
-                );
-
                 let (func_id, mut func) = cx.predefine_function(inst);
 
                 let comments = trans_fn(cx, &mut func, inst);