[Bug fortran/87669] New: Select type, incorrect handling of parameterized derived type

[etdescdev at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87669

            Bug ID: 87669
           Summary: Select type, incorrect handling of parameterized
                    derived type
           Product: gcc
           Version: 8.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: etdescdev at gmail dot com
  Target Milestone: ---

The SELECT TYPE statement matches the class of a parameterized derived type
without checking the kind parameter of the object.
Tested on Ubuntu 18.10 (with gfortran 8.2.0-7ubuntu1 and 9.0.0 20181020
(r265341)) and macOS Mojave (with Homebrew GCC 8.2.0):

Program Devtest
  Type dvtype(k)
    Integer, Kind :: k
    Real(k) :: a, b, c
  End Type dvtype
  type(dvtype(8)) :: dv
  dv%a = 1; dv%b = 2; dv%c = 3
  call dvtype_print(dv)
Contains
  Subroutine dvtype_print(p)
    class(*), intent(in) :: p
    Select Type(p)
    class is (dvtype(4))
      print *, "dvtype4", p%k, p%a, p%b, p%c
    End Select
    Select Type(p)
    class is (dvtype(8))
      print *, "dvtype8", p%k, p%a, p%b, p%c
    End Select
  End Subroutine dvtype_print
End


Output:
 dvtype4           8   0.00000000       0.00000000       1.87500000    
 dvtype8           8   1.0000000000000000        2.0000000000000000       
3.0000000000000000

In this case, the compiler does not display any warning message with -Wall and
-Wextra.
This program compiles and runs without generating any error, yet it prints the
line dvtype4 that does not correspond to the datatype of the object.
In this statement, the kind parameter k is correctly evaluated, but the values
a, b and c are displayed as if k were equal to 4.