The diagind documentation only covers the

diagind(M::AbstractMatrix, k::Integer = 0, indstyle::IndexStyle = IndexLinear())
diagind(M::AbstractMatrix, indstyle::IndexStyle = IndexLinear())

methods requiring the full input matrix. However, there also exist the methods

diagind(m::Integer, n::Integer, k::Integer=0)
diagind(::IndexLinear, m::Integer, n::Integer, k::Integer=0)

only requiring the matrix dimensions, which may prove useful in some cases as pointed out in #1460 by @RoyiAvital. I propose that these methods be added to the corresponding documentation, with examples such as

julia> diagind(5, 7)
1:6:25

julia> diagind(5, 7, 2)
11:6:35

being provided as well.