# Unbox primitive `value` to `mtype`.
	private fun unbox(value: RuntimeVariable, mtype: MType): RuntimeVariable do
		if not value.is_boxed then return value
		if not mtype.is_java_primitive then return value
		if compiler.box_kinds.has(mtype) then
			return new_expr("({mtype.java_type}){value}.value", mtype)
		else
			info "NOT YET IMPLEMENTED unbox for {value} ({mtype})"
			abort
		end
	end