Extracting Struct Decl From Typedef

All, how does one go about extracting the struct declaration
(RecordDecl) from a combined typedef + struct clause in the Clang AST
using a TypedefDecl?

typedef struct FOO{
  int f0;
  int f1;
  int f2;

In visiting a TypedefDecl node, I use:

TypedefDecl *TD = dyn_cast<TypedefDecl>(D);

I would like to retrieve the RecordDecl of the corresponding struct
such that when I clone a new TypedefDecl AST node, I can copy over the
struct linkage with it. Otherwise, the struct ends up with an
anonymous type.

Any thoughts?