Issue discovered when overloading "generic::operator(=)"

Dear Intel Fortran Compiler for Linux and Mac OS X users and developers,

I have discovered an Intel 16.0.0 compiler error (with 15.0.2 is also there) when compiling my Fortran03 software which I believe to be standard conforming. Although this is a quite complex software with many data types, and a complex relationship among them (aggregation, 3-level inheritance hierarchy, etc.), I could already reproduce the compiler error on a simplified test case. In particular, I developed three test cases which are attached to this post. The following outcome was observed for these three test cases:

- overloaded_assignment_test1.f90: compiles and generates the output that I would expect.

amartin@Aetos:~/pruebas_fortran_03$ ifort overloaded_assignment_test1.f90
amartin@Aetos:~/pruebas_fortran_03$ ./a.out
 A_C1_t
 C_C1_t

- overloaded_assignment_test2.f90: DOES NOT COMPILE. I believe it to be standard confirming. Compiler error is as follows:

overloaded_assignment_test2.f90(104): error #6197: An assignment of different structure types is invalid.   [C1]
  B = C1
------^
compilation aborted for overloaded_assignment_test2.f90 (code 1)

Note that the only difference among *test1 and *test2, is that, in the latter, the (abstract) intermediate-level data type, type(C_t), has a deferred TBP, called output_C, which its children, type(C1_t) and type(C2_t), are forced to implement.

- overloaded_assignment_test3.f90. Compiles and generates the output that I would expect.

amartin@Aetos:~/pruebas_fortran_03$ ifort overloaded_assignment_test3.f90
amartin@Aetos:~/pruebas_fortran_03$ ./a.out
 A_C1_t
 C_C1_t

Note that the only difference among *test2 and *test3 is that the overloaded assignment is called with a rhs being of "class(C_t) :: pointer" type previously set to point to the instance of type(C1_t), instead of with a rhs being of type(C1_t) directly.

Could you please help me and confirm my suspicions? (i.e., a compiler related issue) How can it be more elegantly work-arounded?

Thanks very much in advance for your support.