Go version

main

Output of go env in your module/workspace:

irrelevant

What did you do?

Pass %T to a format function with an arg that implements fmt.Formatter

fmt.Formatter.Format is not invoked for %T verb. It's also not documented. I believe %p is the same.

What did you see happen?

The type of the arg is printed, rather than performing the action of fmt.Formatter.Format for the type with the T verb.

What did you expect to see?

The result of executing fmt.Formatter.Format for the arg's type.