void main() { alias Zoo = Foo10056!(false, false, 1); } struct Foo10056(bool S, bool L, size_t N) { string bar() { Appender10056!(string) w; char[] buf; put10056(w, buf); return ""; } public bool opEquals(T)(T other) //const //If you add const, also fails to compile with 2.062. { alias Foo10056!(typeof(this), T, "CMP") P; return false; } } template Foo10056(T, U, string OP) { static if (T.ISEMPTY && U.ISEMPTY) enum bool S = false; else enum bool S = false; alias Foo10056 = Foo10056!(false, false, 0); } /**********************************************/ void put10056(R, E)(ref R r, E e) { static if (is(typeof(r.put(e)))) { r.put(e); } else { static assert(false, "Cannot put a "~E.stringof~" into a "~R.stringof); } } struct Appender10056(A : T[], T) { private template canPutItem(U) { enum bool canPutItem = is(U : T); } private template canPutRange(R) { enum bool canPutRange = is(typeof(Appender10056.init.put(R.init[0]))); } void put(U)(U item) if (canPutItem!U) { char[T.sizeof == 1 ? 4 : 2] encoded; put(encoded[]); } void put(R)(R items) if (canPutRange!R) { } }