As implemented, the header generated for DECLARE_CCTK_ARGUMENTS_func does not check to see whether the thorn has access to a GF that it wants to read or write. In Fortran, this will lead to a compile time error, but in C/C++, the header will simply grant access to the variable.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2369/presync-circumvents-scoping-of-cactus-grid