Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Synods of Sardica, Carthage, Constantinople, and Carthage Under St. Cyprian, Which Canons Were Received by the Council in Trullo and Ratified by II. Nice.: Canon CX

Canon CX.  (Greek cxii. bis)

That infants are baptized for the remission of sins.

Likewise it seemed good that whosoever denies that infants newly from their mother’s wombs should be baptized, or says that baptism is for remission of sins, but that they derive from Adam no original sin, which needs to be removed by the laver of p. 497 regeneration, from whence the conclusion follows, that in them the form of baptism for the remission of sins, is to be understood as false and not true, let him be anathema.

For no otherwise can be understood what the Apostle says, “By one man sin is come into the world, and death through sin, and so death passed upon all men in that all have sinned,” than the Catholic Church everywhere diffused has always understood it.  For on account of this rule of faith (regulam fidei) even infants, who could have committed as yet no sin themselves, therefore are truly baptized for the remission of sins, in order that what in them is the result of generation may be cleansed by regeneration.

Notes.

Ancient Epitome of Canon CX.

Whoso affirms that those newly born and baptized contract nothing from Adam’s transgression, which needs to be washed away by baptism, is to be execrated:  for through one both death and sin invaded the whole world.

This is Canon ij. of Carthage, a.d. 418 [Greek Canon 112].

Johnson.

See Can. 63, 104, both which are double, as this likewise is in the old Greek scholiasts.

[Also it seemed good, that if anyone should say that the saying of the Lord, “In my Father’s house are many mansions” is to be understood as meaning that in the kingdom of heaven there will be a certain middle place, or some place somewhere, in which infants live in happiness who have gone forth from this life without baptism, without which they cannot enter the kingdom of heaven, which is eternal life, let him be anathema.  For after our Lord has said:  “Except a man be born again of water and of the Holy Spirit he shall not enter the kingdom of heaven,” what Catholic can doubt that he who has not merited to be coheir with Christ shall become a sharer with the devil:  for he who fails of the right hand without doubt shall receive the left hand portion.]

Notes.

The foregoing, says Surius, is found in this place in a very ancient codex.  It does not occur in the Greek, nor in Dionysius.  Bruns relegates it to a foot-note.