From a66d3bb056932868dac7ac76d6ed22b09281bc80 Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Wed, 10 Nov 2010 20:24:21 +0000
Subject: [PATCH] Document a language-compatibility issue with function
 parameter names in function prototypes in C++

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@118712 91177308-0d34-0410-b5e6-96231b3b80d8
---
 www/compatibility.html | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/www/compatibility.html b/www/compatibility.html
index c25ea8a4aa..d33686d151 100644
--- a/www/compatibility.html
+++ b/www/compatibility.html
@@ -56,6 +56,7 @@
       <li><a href="#default_init_const">Default initialization of const
       variable of a class type requires user-defined default
       constructor</a></li>
+      <li><a href="#param_name_lookup">Parameter name lookup</a></li>
     </ul>
   </li>
   <li><a href="#objective-c++">Objective-C++ compatibility</a>
@@ -674,6 +675,18 @@ void Bar() {
 }
 </pre>
 
+<!-- ======================================================================= -->
+<h3 id="param_name_lookup">Parameter name lookup</h3>
+<!-- ======================================================================= -->
+
+<p>Due to a bug in its implementation, GCC allows the redeclaration of function parameter names within a function prototype in C++ code, e.g.</p>
+<blockquote>
+<pre>
+void f(int a, int a);
+</pre>
+</blockquote>
+<p>Clang diagnoses this error (where the parameter name has been redeclared). To fix this problem, rename one of the parameters.</p>
+
 <!-- ======================================================================= -->
 <h2 id="objective-c++">Objective-C++ compatibility</h3>
 <!-- ======================================================================= -->
-- 
2.40.0