Technicore Underground Inc. v. Toronto (City), 2012 ONCA 597 declines to decide if waiver and promissory estoppel are essentially the same thing:
 The second matter warranting comment is the City’s contention that waiver and promissory estoppel are one and the same. Based on this view, the City submitted that Clearway had to meet the test for promissory estoppel enunciated by the Supreme Court of Canada in Maracle v. Travellers Indemnity Co. of Canada,  2 S.C.R. 50, at para. 13:
The principles of promissory estoppel are well settled. The party relying on the doctrine must establish that the other party has, by words or conduct, made a promise or assurance which was intended to affect their legal relationship and to be acted on. Furthermore, the representee must establish that, in reliance on the representation, he acted on it or in some way changed his position.
 The Supreme Court decided Saskatchewan River Bungalows a mere three years after Maracle. It did not conflate or equate the requirements for waiver and promissory estoppel in those two cases. Rather, as has been seen, it articulated different requirements for each doctrine. Indeed, at para. 18 of Saskatchewan River Bungalows, after acknowledging that waiver and promissory estoppel are “closely related”, the Supreme Court expressly declined to determine how and whether the two doctrines should be distinguished. Instead, it decided the appeal based on waiver, because that is how “the parties [had] chosen to frame their submissions”.
 There has been much speculation, both judicial and academic, on whether waiver and promissory estoppel are essentially the same thing, with the sole or primary difference being that waiver developed as a common law doctrine whereas promissory estoppel arose in equity. That determination awaits the proper case, one in which it is squarely raised and fully argued. Following the lead of the Supreme Court, I would decide this ground of appeal based on waiver and variation, as that is how Clearway framed the issue. I would add, however, that if the doctrine of promissory estoppel is in play, my conclusion that Clearway has failed to establish the necessary evidentiary basis is reinforced because there is no evidence of detrimental reliance.