SLOAN, J.
This suit was brought by appellant, John McPherson, against appellee, B. Hattich, in the District court of Pima County, to recover upon a contract between appellant and appellee, wherein the former agreed to draw plans and specifications as an architect for a certain building to be erected upon a lot in the city of Tucson owned by appellee, and to superintend the construction thereof for a stipulated per cent of the cost thereof, and wherein the appellee agreed to pay for such services at the rate of the percentage aforesaid; and also to foreclose a lien filed by the appellant upon said property for the amount of said agreed compensation. The notice of lien was referred to in the complaint as constituting a part thereof, and attached to the same as an exhibit. The complaint charged that appellant, after he had partially performed the services agreed upon, was prevented from further performing said services by the acts of appellee. There was no allegation in the complaint that the agreed compensation had not been paid by appellee, nor was there any direct allegation that any sum was due appellant from appellee by reason thereof. There was a statement in the notice of lien that the sum .of seven hundred and fifty dollars was due appellant from appellee as compensation due under said contract at the agreed per cent of the cost of said building. The answer filed by the appellee admitted the residence of the parties, the ownership of the property described in the complaint, the filing of the notice of lien as alleged therein, and denied the remaining allegations of the complaint. The cause was *108tried to a jury. The evidence put in by plaintiff related to the making of the contract sued upon, the work done by him under the contract, and the refusal of appellee to permit appellant to proceed with the work of drawing plans and specifications for the building, and to superintend its erection. No proof was offered or put in by appellant showing non-payment on the part of appellee of the agreed compensation. At the conclusion of appellant’s case counsel for appellee moved the court to instruct the jury to return a verdict in his favor on the ground that the appellant had not made out his case. Thereupon the court did so instruct the jury, and a verdict for the appellee was returned. In accordance with the verdict the court entered judgment in favor of the appellee and against the appellant. From the ruling of the court denying appellant’s motion for a new trial and from the judgment, the appeal is taken.
In the judgment it is recited that the grounds upon which the trial court based its instructions to the jury to return a verdict for the appellee were that it was not alleged in the complaint, nor proven by appellant upon the trial, that he had not been paid for his services. The correctness of this ruling of the court constitutes the sole question raised by the assignments of error. The first question presented is what constitutes a breach of a contract for the rendition of services as an architect and superintendent of construction on the part of the person for whom such services are to be 'rendered, where the latter refuses to permit the former to complete the work agreed to be done. Appellant argues that the breach consists in his refusal to permit the architect to perform the agreed services, that is to say, it consists in the repudiation and abandonment of the contract by the owner of the premises, and does not consist in the non-payment of the agreed compensation. In determining this we have only to consider the question as to what the owner is obligated to do, and what will constitute a full compliance on his part with his contract. In this respect it does not differ from other contracts for the rendition of services on the one part and the payment of an agreed price, or the value of the services by the other. The payment, therefore, of such agreed price, or the value of the services, as the case may be, on the part of the pex’son for whose benefit *109the services are agreed to be rendered, is a complete discharge by him of his obligation. If the person who agrees to perform such services be paid for the same the other party has fully discharged his obligation, and nothing further can be required of him. The breach, therefore, on his part consists in his failure or refusal to pay for the work done or agreed to be done. In the case at bar, therefore, the breach, if any there was, consisted in the refusal or failure of appellee to pay appellant for what was due the latter under the contract. This being true non-payment was an essential allegation of the complaint and a necessary averment to make out a breach of the contract. We do not think that the statement in the notice of lien, filed as an exhibit with the complaint and made a part thereof, can be taken as a substantive allegation of the complaint and to supply its omission to plead by direct averment the nonpayment of whatever may have been due appellant under the contract. In most code states an exhibit cannot be referred to for the purpose of supplying the omission of a material allegation or the curing of a fatal defect. Macdonell v. International etc. Co., 60 Tex. 590; Burkett v. Griffith, 90 Cal. 542, 27 Pac. 527, 13 L. R. A. 707, 25 Am. St. Rep. 151; Brooks v. Paddock, 6 Colo. 36; Pomeroy v. Fullerton, 113 Mo. 440, 21 S. W. 19. In a few states, as in Nebraska, this may be done even to the extent of supplying such a defect. The better rale, in our judgment, is that the office of an exhibit should be limited to the aiding, by amplifying and making more definite and certain, essential allegations of the complaint. In this case, even if the exhibit be referred to for the purpose of supplying the omitted allegation, still non-payment cannot be said to be alleged for the reason that, what may have been true as to the nonpayment at the time the lien was filed, may not have been true at the time suit was brought; and as we hold that nonpayment is the gist of the action, this does not present a case for the application of the rale that a state of facts once shown to exist will be presumed to continue in the absence •of contrary proof.
It is argued by appellant that, admitting the soundness of this rule of pleading, such a defect in the complaint is not ground for an instruction to a jury to find for the de*110fendant. We do not understand this to he the rule. The true rule is that where a complaint fails to state a cause of action it is subject to attack at any stage of the trial, andi may be taken advantage of by demurrer, by objection to the introduction of evidence, or, as was done in the case at bar, by an instruction to the jury. There is some contrariety in- the holdings of the courts in reference to the necessity of proving non-payment by a plaintiff. In California, and some other states, it is held that although nonpayment must be alleged it need not be proven by the plaintiff. Whether this holding be logical or not, and whether this court should follow it, it is unnecessary to decide, inasmuch as we hold that the complaint is fatally defective, and that the defect was such a one as warranted the instructed verdict.
The judgment is therefore affirmed.
KENT, C. J., DOAN, J., and NAVE, J., concur.