[rovingeye]

This has been valid C++ since C++ 11

[direwolf20]

It's unusual. Some, unusual, style guides require it. It's useful in some cases, even necessary in some which is why it was introduced, but not for simple "int"

[rovingeye]

it's literally the exact same thing. We use trailing return types to be consistent across the language.

[direwolf20]

We use trigraphs to be consistent across the language.