You haven't used XCode's Build and Analyze have you?
- There is a bug with the compiler not properly counting references when assigning a variable that needs a release to a property marked "retain". The property will increment the reference count, expecting the caller to decrement it, but the static analyzer does not see this, and so fails to warn.
- http://www.openradar.appspot.com/7338181 - CodeSense fails to work when Static Analysis is turned on.
(DISCLAIMER: I am using Xcode 3.2.1 on Snow Leopard 10.6.3)