Validation misses case where nonexistent output is assigned to Array

[MatthewMah]

The following example passes validation, and I think it should not. I think validation should be able to identify that a nonexistent output field is trying to be read.

workflow ShouldNotValidate{
    call A{}
    Array[File] simple = [A.nonexistent]
    call B{ input:
        in = simple
    }
}

task A{
    command{
        echo "A" > out
    }
    output{
        File out = "out"
    }
}

task B{
    Array[File] in

    command{
        cat ${sep=' ' in}
    }
    output{
    }
}

[mcovarr]

Issue moved to broadinstitute/cromwell #2881 via ZenHub