Redundant operators

[ivan-pi]

module a
    public :: operator(==), operator(.foo.)
    integer :: b = 33
end module
use a
print *,b
end

Flang and gfortran both ignore the operators. ifort and ifx produce an error:

/app/example.f90(2): error #6714: There is no visible interface-stmt that defines this generic-spec.
    public :: operator(==)
--------------^
/app/example.f90(2): error #6714: There is no visible interface-stmt that defines this generic-spec.   [FOO]
    public :: operator(==), operator(.foo.)
----------------------------^