Here is Calvinist W.G.T. Shedd basically affirming that Adam is God:
“In respect to its having no sinful antecedent out of which it is made, sin is origination ex nihilo. Sin is the beginning of something from nothing, and there is this resemblance between it and creation proper. In holy Adam, there was no sinful inclination or corruption that prompted the first transgression. Adam started the wicked inclination itself ex nihilo, by a causative act of self-determination …. But sin differs from creation proper, in that it is not a substance. Creation originates beings and things; but sin is neither a being nor a thing. Yet it is not ‘nothing’ in every sense of the term nothing” (Shedd, Dogmatic Theology, pp. 544-545, single volume edition).
Obviously sin is not a “substance” in the sense of God’s original creation ex nihilo
(i.e., out of nothing). But the origination of sin has to do with God’s
control over things (e.g., Adam) that He has already created. The
question now is what does God’s control over Adam have to do with Adam’s
fall? The answer given by Shedd is that it had nothing to do with
Adam’s fall since to Shedd, God’s control over Adam is non-existent. The
sin in Adam came about ex nihilo, says Shedd. Thus for Shedd,
Adam is God since he is able to bring about things out of nothing. Shedd
endorses the Devil’s lie that man shall be as God. In contrast to
Shedd’s atheistic asininity, God actively caused the evil thoughts and
inclinations in Adam for — gasp! — His own purpose and glory (cf. Ephesians 3:11). When God
caused Adam’s fall, He did not create new material or substance when He
did this, since His causing Adam to fall is simply His controlling what
He has already created.