What are these actions in Xcode 10??? UPDATE: I am stupid! Xcode is showing some contextual actions, like “Discard Change” here. And list of actions could be filtered by typing in Actions text field. I have thought it’s for entering command line actions.

Post of John Sundell about @autoclosure reminded about safe feature of extracting values from dictionaries which I have forgotten about: letterCounts[letter, defaultValue: 0] += 1.

Happy finally to use Dictionary(grouping: students, by: { $0.first! }). But then had to remove that code.