From 3cd9d071c2a03f0a02470d584732ec32f1f96609 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sun, 6 May 2018 21:49:37 -0700
Subject: [PATCH] Fix adjacently tagged empty tuple variant or struct variant

---
 serde_derive/src/ser.rs      |  2 +-
 test_suite/tests/test_gen.rs | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/serde_derive/src/ser.rs b/serde_derive/src/ser.rs
index 987cc53a..38b03eec 100644
--- a/serde_derive/src/ser.rs
+++ b/serde_derive/src/ser.rs
@@ -645,7 +645,7 @@ fn serialize_adjacently_tagged_variant(
 
     let (_, ty_generics, where_clause) = params.generics.split_for_impl();
 
-    let wrapper_generics = if let Style::Unit = variant.style {
+    let wrapper_generics = if fields_ident.is_empty() {
         params.generics.clone()
     } else {
         bound::with_lifetime_bound(&params.generics, "'__a")
diff --git a/test_suite/tests/test_gen.rs b/test_suite/tests/test_gen.rs
index d6921e14..f0255bad 100644
--- a/test_suite/tests/test_gen.rs
+++ b/test_suite/tests/test_gen.rs
@@ -567,6 +567,17 @@ fn test_gen() {
     }
 
     assert::<AssocDeriveMulti<i32, NoSerdeImpl>>();
+
+    #[derive(Serialize)]
+    #[serde(tag = "t", content = "c")]
+    enum EmptyAdjacentlyTagged {
+        #[allow(dead_code)]
+        Struct {},
+        #[allow(dead_code)]
+        Tuple(),
+    }
+
+    assert_ser::<EmptyAdjacentlyTagged>();
 }
 
 //////////////////////////////////////////////////////////////////////////