Currently the code completion and the syntax checker don't support aliased namespaces. This results in code like:

namespace myVeryLongNamedNameSpace 
{
  void myMethod();
}

namespace ns = myVeryLongNamedNameSpace;

ns::myMethod();

where the last line is green underlined, and specifying that "ns is not a namespace or classname" if you hover over it. Also, pressing ctrl-space after "ns::" doesn't result in "myMethod()" popping up.