Oasis cannot get the correct derivative for an expression with 2 variables when the non differentiating variable is an exponent

[TreeSnowFence]

in an expression with 2 variables, in the case that the non differentiating variable is an exponent, oasis will not return the correct derivative for said expression

Here is an example that demonstrates the issue:

dd(2x^y, x)
expected -> 2x^(y-1) * y
actual -> 0

In an ideal world, oasis would correctly evaluate this derivative

issue may be with assuming value of y is 0? I don't think oasis should be assuming this, especially if no prior information about the variable is given