Split TyImplTrait into Universal and Existential

This fixes build after the implementation of impl Trait in argument
position lands in rustc

Author: chrisvittal

clippy_lints/src/lifetimes.rs

@@ -325,7 +325,8 @@ impl<'a, 'tcx> Visitor<'tcx> for RefVisitor<'a, 'tcx> {
             TyPath(ref path) => {
                 self.collect_anonymous_lifetimes(path, ty);
             },
-            TyImplTrait(ref param_bounds) => for bound in param_bounds {
+            TyImplTraitExistential(ref param_bounds) |
+                TyImplTraitUniversal(_, ref param_bounds) => for bound in param_bounds {
                 if let RegionTyParamBound(_) = *bound {
                     self.record(&None);
                 }