It has already been suggested that one of the main purposes of section 2255 was to provide a convenient forum in which the trial judge might testify, if necessary. That purpose is, obviously, contrary to the interpretation rendered in Carvell.

Beyond this inconsistency, Carvell suggests two significant issues: first, that it is highly desirable that the motions be passed upon by the judge who is familiar with the facts; and second, that the criminal trial judge is not likely to be misled by allegations in the 2255 petition as to what had occurred. The first issue raises the question of the proper function of the 2255 judge. Since Carvell was decided before the landmark decision of Townsend v. Sain (which set forth explicit criteria mandating factfinding by the habeas judge), it is appropriate to reconsider the validity of the rationale that there is no impropriety in permitting the judge who tried the criminal case to preside over a 2255 evidentiary hearing attacking the validity of that trial. The second issue raises by implication the question of the propriety of the ·trial judge's acting as both witness and trier of fact in the same proceeding. These issues should be considered in light of the functions and discretionary powers of the 2255 judge.