@stisa Actually, I meant "when sizeof(T) == 1" rather than "if sizeof(T) == 1"
(now corrected). But the problem is, that in the real code I want to support
multiple paramter sizes, and get a compile time error if the size is
unexpected. The example you gave me compiles, but fails at runtime. OTOH, this
led me to find that I can has static asserts (static: assert(false, "invalid
parameter size: " & $sizeof(T))), and that does the trick. Still, it would be
nice if the error pragma supported that too.