Compiler Warning (level 4) C4336

import cross-referenced type library 'type_lib1' before importing 'type_lib2'

A type library was referenced with the #import directive. However, the type library contained a reference to another type library that was not referenced with #import. This other .tlb file was found by the compiler.

Given two type libraries on disk created from the following two files (compiled with midl.exe):

// c4336a.idl
library c4336aLib
   enum E_C4336
      one, two, three

The second type library:

// c4336b.idl
library C4336bLib
   importlib ("c4336a.tlb");
   struct S_C4336
      enum E_C4336 e;

The following sample generates C4336:

// C4336.cpp
// compile with: /W4 /LD
// #import "C4336a.tlb"
#import "C4336b.tlb"   // C4336, uncomment previous line to resolve