Bob (Robert Corbett of Oracle) reports at http://j3-fortran.org/pipermail/j3/2011-January/004136.html that most compilers do not return a BT_CLASS when invoking one of the following procedures; I have not checked - especially as polymorphic arrays are not yet supported. But I wouldn't be surprised if gfortran had the same problems: <quote> The Fortran standard explicitly indicates that a few intrinsic functions (EXTENDS_TYPE_OF, SAME_TYPE_AS, and STORAGE_SIZE) accept polymorphic arguments. The list of intrinsic procedures that satisfy these criteria are ALLOCATED ASSOCIATED EXTENDS_TYPE_OF IMAGE_INDEX IS_CONTIGUOUS LBOUND LCOBOUND MOVE_ALLOC PRESENT SAME_TYPE_AS SHAPE SIZE STORAGE_SIZE THIS_IMAGE UBOUND UCOBOUND [...] This side thinks the following additional functions should accept polymorphic arguments CSHIFT EOSHIFT MERGE PACK RESHAPE SHAPE SIZE SPREAD TRANSFER TRANSPOSE UNPACK </quote> And in a follow up: <quote> None of the implementations I tried treats the results of these intrinsic functions as polymorphic. Some implementations gave no diagnostic message for passing polymorphic acutal arguments to the intrinsic functions, but none allowed the results to be used in contexts that required polymorphism. I admit I find that strange. </quote>
I think the following ones should work fine (re-check?): * ALLOCATED * ASSOCIATED * EXTENDS_TYPE_OF * SAME_TYPE_AS * STORAGE_SIZE The array (+coarray?) intrinsics we can probably ignore for now, since we don't have polymorphic array support at this point. A few ones that are left to check might be: * MOVE_ALLOC * PRESENT * MERGE * ...?
Note: CLASS-support for TRANSFER has been implemented in r193226, cf. PR 54917.