Unrecognized selector sent to instance

As you may or may not know, I do iPhone/Cocoa touch now...

While playing around with something this evening I stumbled across something I thought I'd share:

I received the following error in my Xcode console: "EXC_BAD_INSTRUCTION". More specifically the following was the message: "unrecognized selector sent to instance 0x52d960"...

After looking for some answers in my code and debugging through it, I came across this. When you build in Xcode by using cmd+B you apparently don't build (rebuild that is) the entire solution, but only the classes changed since last build. In my case the above error arose because the class I was working on, "A", called a method on another class "B" further calling a method on a class "C" that had changed signature. "A" was compiled with no errors, and "C" too. But "B" wasn't, and the erroneous method call wasn't caught by the compiler... I did a clean and then a build againg and the coding error was caught.

Just a little something to remember when working with Xcode.