[Bug fortran/49592] New: [OOP] Non-polymorphic ALLOCATE with polymorphic SOURCE= rejected

["burnus at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49592

           Summary: [OOP] Non-polymorphic ALLOCATE with polymorphic
                    SOURCE= rejected
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: burnus@gcc.gnu.org
                CC: janus@gcc.gnu.org


http://j3-fortran.org/doc/meeting/195/11-194r1.txt

According to the first round of interpretation requests (namely: J3, WG5 will
follow later), the following program is valid. gfortran rejects it with:

    Allocate(y,Source=x)               ! (*)
             1        2
Error: Type of entity at (1) is type incompatible with source-expr at (2)


  Program m195_m1
    Type t
      Real c
    End Type
    Type,Extends(t) :: t2
      Real d
    End Type
    Class(t),Allocatable :: x
    Type(t),Allocatable :: y
    Allocate(x,Source=t2(1.5,-1.5))
    Allocate(y,Source=x)               ! (*)
!    ...
  End Program


Proposed edits:

[128:24] In 6.7.1.2p7, before "On successful", insert
  "If an <allocate-object> is not polymorphic and the <source-expr> is
   polymorphic with a dynamic type that differs from its declared
   type, the value provided for that <allocate-object> is the ancestor
   component of the <source-expr> that has the type of the
   <allocate-object>; otherwise, the value provided is the value of
   the <source-expr>."
[128:25-26] Replace "that of <source-expr>" with "the value provided",
            twice.