The Bladesigner Wizard's Extra Attack feature reads:
You can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks.
Notably, all but three cantrips have a casting time of 1 Action. Two cantrips, shillelagh and magic stone, have a casting time of 1 Bonus Action, and the cantrip mending has a casting time of 1 minute.
Can these cantrips be cast with the Bladesinger's Extra Attack feature, despite not having casting times of 1 Action? And particular to mending, does it take effect immediately, or does it still take a minute to complete casting?
(Nevermind how our Wizard learned shillelagh or magic stone, perhaps they took a 1 level dip into druid when they went hiking during a gap year in their studies.)