If a typedef refers to a type that is defined in an included IDL file, the code for the typedef is not generated. Furthermore, the Compiler issues a warning about pending typedefs.
If the typedef is used elsewhere in the code, the generated code cannot be compiled because of the missing code for the pending typedefs.
Inner IDL file:
Outer IDL file:
In this example, the typedef for OuterStruct is not generated, thus Delphi fails to compile OuterContainer.