This is not different than having foo_bar and foo_Bar as two different variables.
And its worse, especially when the variables aren't "foo_bar" and "foo_Bar", but, say, "cycle_often" and "cycle_of_ten".
Such an error is caught by the compiler.
const cycle_often = 10
var cycle_of_ten : float
ambig.nim:2:5: Error: redefinition of 'cycle_of_ten'