https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94599
Bug ID: 94599
Summary: Invalid constructor for derived types with recursive
allocatable components
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: pault at gcc dot gnu.org
Target Milestone: ---
Created attachment 48271
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48271&action=edit
A kludge to fix the problem
module m
type :: stack_t
integer :: index
type(stack_t), allocatable :: payload
type(stack_t), allocatable :: next
end type stack_t
end module
use m
type (stack_t) :: start
print *, allocated(start%payload), allocated(start%next)
start = stack_t(index=42) ! Should provide NULL for both 'payload' and
'next'
print *, allocated(start%payload), allocated(start%next)
end
should output
F F
F F
but, instead, outputs
F F
F T
The reason for this is apparent on compilation with the option
-fdump-parse-tree.
start = stack_t(index=42) generates
ASSIGN MAIN__:start stack_t(42 , () , stack_t(() , NULL()))
The appearance of the constructor for the 'next' component is wrong. It should
be NULL(), since this is a missing component in the constructor. (F2018: 7.5.10
Construction of derived-type values)
Note that 'payload' is correct. Any number of subsequent components of the
parent type are incorrect.
I cannot see, at present, what the problem is caused by. Evidently, somewhere,
the default_initializer is applied.
The attached is a kludge that fixes the problem and regtests OK but is
incorrect.
Paul
