A vector subscript can have repeated elements, creating a many-one section,
for example
x([1,2,1])
Such a section must not appear on the left hand side of an assignment, because of
the ambiguity, but some compilers do not catch this.
program many_one
implicit none
integer, parameter :: ncou = 4
character (len=6) :: continents(2) = ["Asia ","Europe"]
character (len=6) :: countries(ncou) = &
["France","Japan ","China ","Italy "]
integer :: ic(ncou) = [2, 1, 1, 2]
character (len=*), parameter :: fmt = "(*(a10))"
print fmt, "country",countries
print fmt, "continent",continents(ic)
! line above is a valid many-one section
! line below is invalid since many-one array section
! must not appear on left hand side
continents(ic) = ["a","b","c","d"]
print fmt, continents
end program many_one
! gfortran and Intel Fortran output is below.
! They do not catch the invalid many-one assignment.
!
! country France Japan China Italy
! continent Europe Asia Asia Europe
! c d
A vector subscript can have repeated elements, creating a many-one section, for example
x([1,2,1])Such a section must not appear on the left hand side of an assignment, because of the ambiguity, but some compilers do not catch this.