Auto merge of #3633 - matthiaskrgr:rustup, r=phansch

rustup (don't know the exact PR unfortunately)

Author: bors

clippy_lints/src/consts.rs

@@ -304,7 +304,7 @@ impl<'c, 'cc> ConstEvalLateContext<'c, 'cc> {
                 };
 
                 let result = self.tcx.const_eval(self.param_env.and(gid)).ok()?;
-                let ret = miri_to_const(self.tcx, result);
+                let ret = miri_to_const(self.tcx, &result);
                 if ret.is_some() {
                     self.needed_resolution = true;
                 }

clippy_lints/src/enum_clike.rs

@@ -70,7 +70,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnportableVariant {
                         promoted: None,
                     };
                     let constant = cx.tcx.const_eval(param_env.and(c_id)).ok();
-                    if let Some(Constant::Int(val)) = constant.and_then(|c| miri_to_const(cx.tcx, c)) {
+                    if let Some(Constant::Int(val)) = constant.and_then(|c| miri_to_const(cx.tcx, &c)) {
                         let mut ty = cx.tcx.type_of(def_id);
                         if let ty::Adt(adt, _) = ty.sty {
                             if adt.is_enum() {

clippy_lints/src/len_zero.rs

@@ -302,10 +302,15 @@ fn has_is_empty(cx: &LateContext<'_, '_>, expr: &Expr) -> bool {
 
     let ty = &walk_ptrs_ty(cx.tables.expr_ty(expr));
     match ty.sty {
-        ty::Dynamic(ref tt, ..) => cx
-            .tcx
-            .associated_items(tt.principal().def_id())
-            .any(|item| is_is_empty(cx, &item)),
+        ty::Dynamic(ref tt, ..) => {
+            if let Some(principal) = tt.principal() {
+                cx.tcx
+                    .associated_items(principal.def_id())
+                    .any(|item| is_is_empty(cx, &item))
+            } else {
+                false
+            }
+        },
         ty::Projection(ref proj) => has_is_empty_impl(cx, proj.item_def_id),
         ty::Adt(id, _) => has_is_empty_impl(cx, id.did),
         ty::Array(..) | ty::Slice(..) | ty::Str => true,