http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57957
--- Comment #3 from Tao Song <songtao.thu at gmail dot com> --- (In reply to janus from comment #2) > (In reply to Tobias Burnus from comment #1) > > For GCC 4.9, one needs to wrap the code in the main program in BLOCK/END > > BLOCK as otherwise the end-of-scope deallocation does not trigger, which > > causes the failure. > > Updated test case: > > > program main > > implicit none > > type :: type1 > real, allocatable :: anum(:) > end type > > type :: type2 > type(type1) :: temp > end type > > > block > type(type1) :: t1 > type(type2) :: t2 > > t1 = type1([0.,1.]) > t2 = type2(t1) > end block > end > > > > Note: The double free goes away when changing the line > > t2 = type2(t1) > > to > > t2%temp = t1 > > That means the actual problem is not the auto-dealloc itself (which is done > properly), but the construction of t2: With the second variant, a deep copy > is done (allocating a separate chunk of memory for t2%temp), while in the > first one t2%temp only gets a reference to the memory allocated for t1 > (which is of course wrong). Since both t1 and t2 are auto-deallocated, we > try to free that memory twice. Do you mean in fortran the default structure constructor would yield a shadow copying? Is this in the standard? Thank you. Tao Song
