For instance
static assert(!__traits(compiles, { char[] f() { char[2] x;return x[].splitterASCII!(_ => _ == ' ').front;
} })); at https://github.com/nordlow/phobos-next/blob/bd2fe42978aab2313977042c858d77c5766538e8/src/splitter_ex.d#L110 Or do I have to write a trait myself?