Extended Description

I built with a recent version of the clang-tidy

rnburn@localhost ~/bugs/ns-clang-tidy $ clang-tidy --version
LLVM (http://llvm.org/):
LLVM version 3.7.0svn
Optimized build.
Built Mar 30 2015 (04:29:52).
Default target: x86_64-unknown-linux-gnu
Host CPU: core-avx2

If I set up this file

//test.cpp
namespace a { namespace b {

void f() {
}

}}

Then run

clang-tidy -fix test.cpp -checks='*' -- -x c++ -std=c++1y -stdlib=libc++

It generates this file

//test.cpp -fixed
namespace a { namespace b {

void f() {
}

} // namespace b
// namespace a

Note that it left out one of the closing braces for the namespace and breaks the source code.