Please describe the problem:
When doxygen encounters a using declaration for a type which is a typedef to a
non-class type (i.e. builtin type such as in), getResolvedClass() returns
incorrect results which causes findUsingDeclarations() to incorrectly generate a
"bogus" ClassDef for the type rather than using the MemberDef representing the
typedef. As a result, failures to resolve a method definition with its
declaration can result

Steps to reproduce:
1. Run doxygen against the following source:

namespace a {
   /// typedef doc
   typedef uint32_t A;
}

namespace b {
   /// class doc.
   class B {
      public:
      /// fun doc.
      void fun(a::A arg);
   };
}

using a::A;

namespace b {
   /** detailed doc. */
   void B::fun(A arg) {}
}



Actual results:
The following error message is generated:

/home/scp/bug.cpp:19: Warning: no matching class member found for
  void b::B::fun(A arg)
Possible candidates:
  void b::B::fun(a::A arg)


Expected results:
No error message

Does this happen every time?
yes

Other information:
The problem occurs when the type in the using declaration is a typedef to a
non-class type, because getResolvedClassRec() is failing to return the MemberDef
for a typedef which does not resolve to a class type. As a result,
findUsingDeclarations() ends up creating and installing a "bogus" <using>
ClassDef to represent the imported type. If the method definition then uses this
imported type, it will not resolve with the method declaration (which is assumed
to be using the same type but not via a using declaration).

It should be noted that this same input will generate the same error for other
reasons unless the (currently proposed) patch for PR 333053 has already been
applied, in which case the problem discussed here is unmasked.

I include a proposed patch in the following attachment.