https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63552
--- Comment #7 from Tobias Burnus <burnus at gcc dot gnu.org> --- (In reply to Ian Harvey from comment #6) > Note that using a type bound procedure (versus a procedure component) as an > actual argument is an extension to Fortran 2008. Can you pinpoint this in the standard? At a glance, it seems to be supported: R1223 procedure-designator is procedure-name or proc-component-ref or data-ref % binding-name "12.2.2.3 Dummy procedures A dummy argument that is specified to be a procedure or appears as the procedure designator in a procedure reference is a dummy procedure. A dummy procedure with the POINTER attribute is a dummy procedure pointer." Quotes from the Fortran 2015 draft J3/14-007r2.