http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49213
Summary: [OOP] gfortran rejects structure constructor
expression
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: fortran
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: neil.n.carl...@gmail.com
In the following program type-compatible variables are used as an expression in
a structure constructor for an allocatable CLASS(S) component. In the first
case a TYPE(S) variable is used, and in the second a TYPE(S2), where S2 extends
S.
The program compiles with nagfor 5.2 and (reportedly) with the cray compiler,
but gfortran rejects the code with the error messages:
Tobj = T(Sobj)
1
Error: Can't convert TYPE(s) to CLASS(s) at (1)
Tobj = T(S2obj)
1
Error: Can't convert TYPE(s2) to CLASS(s) at (1)
===============
>From the F2008 standard:
"For a nonpointer component, the declared type and type parameters of the
component and expr shall conform in the same way as for a variable and expr in
an intrinsic assignment statement (7.2.1.2) [...]" (4.5.10p2)
"if the variable is polymorphic it shall be type compatible with expr; [...]"
(7.2.1.2p1(4))
Also 4.5.10 p6 applies to allocatable components.
===============
program main
type :: S
integer :: n
end type
type(S) :: Sobj
type, extends(S) :: S2
integer :: m
end type
type(S2) :: S2obj
type :: T
class(S), allocatable :: x
end type
type(T) :: Tobj
Sobj = S(1)
Tobj = T(Sobj)
S2obj = S2(1,2)
Tobj = T(S2obj)
end program
