.. At least in 2.054


import std.string;
void main() {
    format("%1$s", "a");
}

std.format.FormatError: std.format string

Using formattedWrite works:

import std.format, std.range;
void main() {
    auto app = appender!string();
    formattedWrite(app, "%1$s", "a");
    assert(app.data == "a");
}