Defendant, who was charged with kidnapping, theft, and simple robbery, pleaded guilty to simple robbery. He appeals from that conviction, asserting for the first time on this appeal that he should be permitted to withdraw his plea of guilty on the ground that the prosecution failed to fulfill its part of an alleged plea bargain with respect to the sentence imposed. Although we might infer from the proceedings that there was some form of plea bargain, the record does not disclose the terms of the agreement. We are accordingly unable to decide the question without the kind of record which an evidentiary hearing in a postconviction *416proceeding would establish. State v. Coe, 290 Minn. 537, 188 N. W. 2d 421 (1971).

Affirmed.