Auto merge of #1396 - tathanhdinh:master, r=emilio

PartialOrd and Ord for enum

Hello all,
This PR tries to fix #1395.
Many thanks for any comment.

3 files changed, 51 insertions, 3 deletions

diff --git a/src/codegen/mod.rs b/src/codegen/mod.rs
index 1bff1e26..7e183ad5 100644
--- a/src/codegen/mod.rs
+++ b/src/codegen/mod.rs
@@ -2590,9 +2590,17 @@ impl CodeGenerator for Enum {
         }
 
         if !variation.is_const() {
-            attrs.push(attributes::derives(
-                &["Debug", "Copy", "Clone", "PartialEq", "Eq", "Hash"],
-            ));
+            let mut derives = vec!["Debug", "Copy", "Clone", "PartialEq", "Eq", "Hash"];
+
+            if item.can_derive_partialord(ctx) {
+                derives.push("PartialOrd");
+            }
+
+            if item.can_derive_ord(ctx) {
+                derives.push("Ord");
+            }
+
+            attrs.push(attributes::derives(&derives));
         }
 
         fn add_constant<'a>(
diff --git a/tests/expectations/tests/ord-enum.rs b/tests/expectations/tests/ord-enum.rs
new file mode 100644
index 00000000..579817bc
--- /dev/null
+++ b/tests/expectations/tests/ord-enum.rs
@@ -0,0 +1,25 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(
+    dead_code,
+    non_snake_case,
+    non_camel_case_types,
+    non_upper_case_globals
+)]
+
+#[repr(i32)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub enum A {
+    A0 = 0,
+    A1 = 1,
+    A2 = 2,
+    A3 = -1,
+}
+#[repr(i32)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub enum B {
+    B0 = 1,
+    B1 = 4,
+    B2 = 3,
+    B3 = -1,
+}
diff --git a/tests/headers/ord-enum.h b/tests/headers/ord-enum.h
new file mode 100644
index 00000000..364f711e
--- /dev/null
+++ b/tests/headers/ord-enum.h
@@ -0,0 +1,15 @@
+// bindgen-flags: --rustified-enum * --with-derive-ord
+
+enum A {
+	A0 = 0,
+	A1 = 1,
+	A2 = 2,
+	A3 = A0 - 1,
+};
+
+enum B {
+	B0 = 1,
+	B1 = B0 + 3,
+	B2 = B0 + 2,
+	B3 = B0 - 2,
+};
\ No newline at end of file