Common gotchas

The "what bit me in code review" survival kit:

Loop variable capture (Go 1.22+ helped, but you should still know).
Nil interface vs nil concrete (a non-nil pointer inside an interface variable makes the interface non-nil).
Slice aliasing — two slices sharing a backing array.
Goroutine leaks — a goroutine waiting on a channel that nobody will ever send to.

exercises

9 ready

Interface nil vs concrete nil — Go's most-famous trap.

Slice aliasing. Pick what prints:

Goroutine leaks. Pick the statement that BEST

Fill in the keyword. Loop variable capture in

Type the builtin function used to FORCE a fresh backing