From 055a654a3d7a0e6c4dfebee70d135342299a00d2 Mon Sep 17 00:00:00 2001
From: Dirkjan Ochtman <dirkjan@ochtman.nl>
Date: Mon, 21 Nov 2022 20:33:11 -0800
Subject: [PATCH] Add support for generic type arguments

---
 instant-xml-macros/src/lib.rs |  6 ++++++
 instant-xml-macros/src/ser.rs |  9 ++++++++-
 instant-xml/tests/generics.rs | 26 ++++++++++++++++++++++++++
 3 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 instant-xml/tests/generics.rs

diff --git a/instant-xml-macros/src/lib.rs b/instant-xml-macros/src/lib.rs
index e4eb3e4..b80662f 100644
--- a/instant-xml-macros/src/lib.rs
+++ b/instant-xml-macros/src/lib.rs
@@ -79,6 +79,12 @@ impl<'input> ContainerMeta<'input> {
             .extend(xml_generics.lifetimes().map(|lt| lt.lifetime.clone()));
         xml_generics.params.push(xml.into());
 
+        for param in xml_generics.type_params_mut() {
+            param
+                .bounds
+                .push(syn::parse_str("::instant_xml::FromXml<'xml>").unwrap());
+        }
+
         xml_generics
     }
 
diff --git a/instant-xml-macros/src/ser.rs b/instant-xml-macros/src/ser.rs
index 3cc5d90..750d307 100644
--- a/instant-xml-macros/src/ser.rs
+++ b/instant-xml-macros/src/ser.rs
@@ -91,7 +91,14 @@ fn serialize_struct(
         ));
     }
 
-    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+    let mut generics = input.generics.clone();
+    for param in generics.type_params_mut() {
+        param
+            .bounds
+            .push(syn::parse_str("::instant_xml::ToXml").unwrap());
+    }
+
+    let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
     let tag = meta.tag();
     let ident = &input.ident;
 
diff --git a/instant-xml/tests/generics.rs b/instant-xml/tests/generics.rs
new file mode 100644
index 0000000..5664be4
--- /dev/null
+++ b/instant-xml/tests/generics.rs
@@ -0,0 +1,26 @@
+use instant_xml::{from_str, to_string, FromXml, ToXml};
+
+#[derive(Debug, Eq, FromXml, ToXml, PartialEq)]
+struct Foo<T> {
+    inner: T,
+}
+
+#[derive(Debug, Eq, FromXml, ToXml, PartialEq)]
+struct Bar {
+    bar: String,
+}
+
+#[allow(clippy::disallowed_names)]
+#[test]
+fn serialize_generics() {
+    let foo = Foo {
+        inner: Bar {
+            bar: "Bar".to_owned(),
+        },
+    };
+
+    let xml = "<Foo><Bar><bar>Bar</bar></Bar></Foo>";
+
+    assert_eq!(to_string(&foo).unwrap(), xml);
+    assert_eq!(from_str::<Foo<Bar>>(xml).unwrap(), foo);
+}