Add a test for dupe enums and namespaces.

I feared that this might fail, but it doesn't! :)

tests/expectations/tests/dupe-enum-variant-in-namespace.rs

@@ -0,0 +1,30 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(
+    dead_code,
+    non_snake_case,
+    non_camel_case_types,
+    non_upper_case_globals
+)]
+
+#[allow(non_snake_case, non_camel_case_types, non_upper_case_globals)]
+pub mod root {
+    #[allow(unused_imports)]
+    use self::super::root;
+    pub mod foo {
+        #[allow(unused_imports)]
+        use self::super::super::root;
+        impl root::foo::Bar {
+            pub const Foo1: root::foo::Bar = Bar::Foo;
+        }
+        impl root::foo::Bar {
+            pub const Foo3: root::foo::Bar = Bar::Foo2;
+        }
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum Bar {
+            Foo = 0,
+            Foo2 = 1,
+        }
+    }
+}

tests/headers/dupe-enum-variant-in-namespace.h

@@ -0,0 +1,10 @@
+// bindgen-flags: --rustified-enum ".*" --enable-cxx-namespaces -- -x c++
+
+namespace foo {
+  enum class Bar : unsigned {
+    Foo = 0,
+    Foo1 = 0,
+    Foo2,
+    Foo3 = Foo2,
+  };
+}