In that event the injured party is unable to complete the work himself and, subject to the restrictions of sections 3300 and 3359 of the Civil Code, the proper measure of damages is the difference in value of the property with and without the promised performance, since that is the contractual benefit of which the injured party is deprived. ( Knoch v. Haizlip, 163 Cal. 146, 154 [ 124 P. 998]; South Memphis Land Co. v. McLean Hardwood Lbr. Co., 179 F. 417, 423-424 [102 C.C.A. 563]; Hyatt v. Wiggins, 178 Ark. 1085 [ 13 S.W.2d 301, 303].) In the present case the contract was to be performed entirely on property that is not owned by plaintiffs.

This question must be answered in the affirmative. The law is settled in California that it is reversible error for the trial court to fail to make a finding upon a material issue properly raised by the pleadings if, as in the instant case, there is any evidence which would support a finding in favor of such defense ( Due v. Swartz, 22 Cal.App. (2d) 217, 218 [ 70 P.2d 716]; Lyden v. Spohn-Patrick Co., 155 Cal. 177, 182 [ 100 P. 236]; Knoch v. Haizlip, 163 Cal. 146, 153 [ 124 P. 998].) There is no merit in plaintiffs' assertion that defendant is estopped from invoking the defense of the statute of frauds, for the reason that estoppel as to any defense which would otherwise be available to the defendant (appellant) under the facts stated in a complaint may not be relied upon by the plaintiff (respondent) unless the estoppel is pleaded ( Cohen v. Metropolitan Life Ins. Co., 32 Cal.App. (2d) 337, 347 [ 89 P.2d 732].)