FoBiS.py

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COR022 missing-default-pointer-initialisation ​

warning enabled by default

A pointer component of a derived type has no default initialisation (=> null()).

Why ​

A pointer component without default initialisation starts with an undefined association status, not a disassociated one: associated(obj%p) on a fresh object is not allowed and returns garbage in practice, so code that tests it before use crashes or follows a wild pointer. => null() in the component declaration makes every new object start disassociated.

Reported ​

fortran
type :: node
  type(node), pointer :: next
end type node

Preferred ​

fortran
type :: node
  type(node), pointer :: next => null()
end type node

Suppressing ​

For one occurrence, with the reason on the same line (or alone on the line before the statement):

fortran
! fobis: ignore[COR022] <why this occurrence is fine>

For the whole project, ignore = COR022 in the fobos [lint] section.

Equivalent ​

Fortitude rule C101 (see Lint Rules).