My reading of both Fortran 2003 and Fortran 2008 (7.4.1.3, page 141) is that it should call my defined assignment for the explicit one between checkpoints Bravo and Charlie as well as for the one before Alpha.
MODULE Assign
IMPLICIT NONE
TYPE, PUBLIC :: Mytype
INTEGER :: comp = 123
CONTAINS
PROCEDURE, PRIVATE :: Copy
GENERIC :: ASSIGNMENT (=) => Copy
END TYPE Mytype
CONTAINS
SUBROUTINE Copy (a, b)
CLASS(Mytype), INTENT(OUT) :: a
CLASS(Mytype), INTENT(IN) :: b
PRINT *, 'Copying', b%comp
a%comp = b%comp
END SUBROUTINE Copy
END MODULE Assign
PROGRAM Main
USE Assign
IMPLICIT NONE
TYPE :: Weeble
TYPE(Mytype), ALLOCATABLE :: arr
END TYPE Weeble
TYPE(Mytype) :: this, that
TYPE(Weeble) :: object, temp
that%comp = 456
this = that
PRINT *, 'Checkpoint Alpha'
call Cheque(this)
PRINT *, 'Checkpoint Bravo'
ALLOCATE(object%arr)
object%arr%comp = 123
temp = object
PRINT *, 'Checking', object%arr%comp
PRINT *, 'Checkpoint Charlie'
CALL Check(temp)
CONTAINS
SUBROUTINE Cheque (arg)
TYPE(Mytype), VALUE :: arg
PRINT *, 'Checking', arg%comp
END SUBROUTINE Cheque
SUBROUTINE Check (arg)
TYPE(Weeble), VALUE :: arg
PRINT *, 'Checking', arg%arr%comp
END SUBROUTINE Check
END PROGRAM Main
