From a732b9bad36ef3384334a5e4706b1ccc298720cc Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Fri, 19 Aug 2016 11:12:38 -0400
Subject: [PATCH] Fix codegen with lifetimes but no type parameters

---
 serde_codegen/src/de.rs   |  2 +-
 testing/tests/test_gen.rs | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/serde_codegen/src/de.rs b/serde_codegen/src/de.rs
index bbcb30e9..b630ede0 100644
--- a/serde_codegen/src/de.rs
+++ b/serde_codegen/src/de.rs
@@ -192,7 +192,7 @@ fn deserialize_visitor(
     builder: &aster::AstBuilder,
     generics: &ast::Generics,
 ) -> (P<ast::Item>, P<ast::Ty>, P<ast::Expr>) {
-    if generics.ty_params.is_empty() {
+    if generics.lifetimes.is_empty() && generics.ty_params.is_empty() {
         (
             builder.item().unit_struct("__Visitor"),
             builder.ty().id("__Visitor"),
diff --git a/testing/tests/test_gen.rs b/testing/tests/test_gen.rs
index 0acfdb36..7d648f57 100644
--- a/testing/tests/test_gen.rs
+++ b/testing/tests/test_gen.rs
@@ -6,6 +6,7 @@ extern crate serde;
 use self::serde::ser::{Serialize, Serializer};
 use self::serde::de::{Deserialize, Deserializer};
 
+use std::borrow::Cow;
 use std::marker::PhantomData;
 
 //////////////////////////////////////////////////////////////////////////
@@ -177,6 +178,15 @@ fn test_gen() {
         e: E,
     }
     assert::<WithTraits2<X, X>>();
+
+    #[derive(Serialize, Deserialize)]
+    struct CowStr<'a>(Cow<'a, str>);
+    assert::<CowStr>();
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(bound(deserialize = "T::Owned: Deserialize"))]
+    struct CowT<'a, T: ?Sized + 'a + ToOwned>(Cow<'a, T>);
+    assert::<CowT<str>>();
 }
 
 //////////////////////////////////////////////////////////////////////////