F08: Internal compiler error on code using initialization by default constructors

[difference-scheme]

Error message:

Lowering Error: unknown source type for conversion to integer*8 [ast=13,asttype=1,datatype=0]
F90-F-0000-Internal compiler error. Errors in Lowering       1  (test.f90: 16)
F90/x86-64 Linux Flang - 1.5 2017-05-01: compilation aborted

Code:

program test

   type :: First
   end type First
   
   type :: Second
      class(First), allocatable :: obj
   end type Second

   class(First),  allocatable :: obj1
   class(Second), allocatable :: obj2

   obj1 = First()
   obj2 = Second(obj1)
   
end program test

[PiotrRoguski]

I guess the root cause of this issue is miss determining the type. This leads to evaluating if expression in lowerexp.c line 1227 as false and falling into conversion switch-case.

Below code doesn't reproduce this issue:

program test
   type :: First
       integer :: i
   end type First
   
   type :: Second
      class(First), allocatable :: obj
   end type Second

   class(First),  allocatable :: obj1
   class(Second), allocatable :: obj2

   obj1 = First(1)
   obj2 = Second(obj1)
   
end program test