Fortran: [PDT] Fix faults in fiats runtime [PR123545,PR123673,PR122949]

Fortran: [PDT] Fix faults in fiats runtime [PR123545,PR123673,PR122949]

2026-02-08  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/123545
	PR fortran/123673
	* decl.cc (gfc_get_pdt_instance): If a pdt_type component is
	allocatable or has allocatable components, mark it alloc_comp.
	(gfc_match_decl_type_spec): Sometimes in compiling contained
	functions, the symtree for the constructor points to the type
	instead of the constructor symbol. This corrects itself later
	in compilation so return MATCH_YES.
	* trans-decl.cc (gfc_generate_function_code): Unconditionally
	nullify allocatable components as well as applying the default
	initializer.
	* trans-expr.cc (gfc_trans_alloc_subarray_assign): Restrict the
	freeing of the destination data to non-allocatable expressions
	and, instead, add the se finalblock to the encompassing final_
	block.

gcc/testsuite
	PR fortran/123545
	* gfortran.dg/pdt_82.f03: New test.

	PR fortran/123673
	* gfortran.dg/pdt_83.f03: New test.

	PR fortran/122949
	* gfortran.dg/pr122949.f90: New test.