Go's preferred way would probably be something like compute the aliased operations on the line(s) before, then reference the final values.

E.G. Adapting https://github.com/golang/go/issues/34174

    f := 123.45
    fmt.Fprintln("value=%08.3f{f}") // value=0123.450
    fmt.Fprintln("value=%08.3f", f) // value=0123.450
    s := "value"
    fmt.Fprintln("value='%50s{s}'") // value='<45 spaces>value'
    fmt.Fprintln("value='%50s'", s) // value='<45 spaces>value'

    fmt.Fprintln("value=%08.3f%{f}") // value=0123.450
    fmt.Fprintln("value='%50s%{s}'") // value='<45 spaces>value'