Fortran 2003 has in Section 7.4.1.2: "In an intrinsic assignment statement, variable shall not be polymorphic, and [...]"
Fortran 2008 has in Section 7.2.1.2 "If variable is a coindexed object, the variable * shall not be polymorphic, [...]" and the previous restriction has been removed. -- Summary: [OOP][F2008] Intrinsic assign to polymorphic variable Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: burnus at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43366