From f9b8512dc298e7e2bcd955ee89cda1e659f77a5c Mon Sep 17 00:00:00 2001
From: Ingvar Stepanyan <me@rreverser.com>
Date: Tue, 30 Jan 2018 21:35:42 +0000
Subject: [PATCH] Wrap tag into anonymous struct in C++

Fixes #122
---
 src/bindgen/ir/enumeration.rs       | 14 ++++++++++++++
 tests/expectations/display_list.cpp |  4 +++-
 tests/expectations/enum.cpp         |  4 +++-
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/bindgen/ir/enumeration.rs b/src/bindgen/ir/enumeration.rs
index a21f1e4..cf34fd6 100644
--- a/src/bindgen/ir/enumeration.rs
+++ b/src/bindgen/ir/enumeration.rs
@@ -357,7 +357,21 @@ impl Source for Enum {
                 out.open_brace();
             }
 
+            // C++ allows accessing only common initial sequence of union
+            // branches so we need to wrap tag into an anonymous struct
+            let wrap_tag = config.language == Language::Cxx && !separate_tag;
+
+            if wrap_tag {
+                out.write("struct");
+                out.open_brace();
+            }
+
             write!(out, "{} tag;", enum_name);
+
+            if wrap_tag {
+                out.close_brace(true);
+            }
+
             out.new_line();
 
             if separate_tag {
diff --git a/tests/expectations/display_list.cpp b/tests/expectations/display_list.cpp
index 82f73cf..4833de0 100644
--- a/tests/expectations/display_list.cpp
+++ b/tests/expectations/display_list.cpp
@@ -34,7 +34,9 @@ union DisplayItem {
     Rect bounds;
   };
 
-  Tag tag;
+  struct {
+    Tag tag;
+  };
   Fill_Body fill;
   Image_Body image;
 };
diff --git a/tests/expectations/enum.cpp b/tests/expectations/enum.cpp
index 8744afd..c90c2d4 100644
--- a/tests/expectations/enum.cpp
+++ b/tests/expectations/enum.cpp
@@ -56,7 +56,9 @@ union F {
     int16_t y;
   };
 
-  Tag tag;
+  struct {
+    Tag tag;
+  };
   Foo_Body foo;
   Bar_Body bar;
 };