# Handle common special cases before doing the effective method invocation
	# This methods handle the `==` and `!=` methods and the case of the null receiver.
	# Note: a { is open in the generated C, that enclose and protect the effective method invocation.
	# Client must not forget to close the } after them.
	#
	# The value returned is the result of the common special cases.
	# If not null, client must compile it with the result of their own effective method invocation.
	#
	# If `before_send` can shortcut the whole message sending, a dummy `if(0){`
	# is generated to cancel the effective method invocation that will follow
	# TODO: find a better approach
	private fun before_send(res: nullable RuntimeVariable, mmethod: MMethodDef, arguments: Array[RuntimeVariable]) do
		var bool_type = compiler.mainmodule.bool_type
		var recv = arguments.first
		var consider_null = mmethod.name == "==" or mmethod.name == "!=" or mmethod.name == "is_same_instance"
		if recv.mcasttype isa MNullableType or recv.mcasttype isa MNullType then
			add("if ({recv} == null || {recv}.is_null()) \{")
			if mmethod.name == "==" or mmethod.name == "is_same_instance" then
				if res == null then res = new_var(bool_type)
				var arg = arguments[1]
				if arg.mcasttype isa MNullableType then
					add("{res} = ({arg} == null || {arg}.is_null());")
				else if arg.mcasttype isa MNullType then
					add("{res} = true; /* is null */")
				else
					add("{res} = false; /* {arg.inspect} cannot be null */")
				end
			else if mmethod.name == "!=" then
				if res == null then res = new_var(bool_type)
				# res = self.new_var(bool_type)
				var arg = arguments[1]
				if arg.mcasttype isa MNullableType then
					add("{res} = ({arg} != null && !{arg}.is_null());")
				else if arg.mcasttype isa MNullType then
					add("{res} = false; /* is null */")
				else
					add("{res} = true; /* {arg.inspect} cannot be null */")
				end
			else
				add_abort("Receiver is null")
				ret(null_instance)
			end
			add("\} else \{")
		else
			add "\{"
			add "/* recv ({recv}) cannot be null since it's a {recv.mcasttype}"
		end
		if consider_null then
			var arg = arguments[1]
			if arg.mcasttype isa MNullType then
				if res == null then res = new_var(bool_type)
				if mmethod.name == "!=" then
					add("{res} = true; /* arg is null and recv is not */")
				else # `==` and `is_same_instance`
					add("{res} = false; /* arg is null but recv is not */")
				end
				add("\}") # closes the null case
				add("if (false) \{") # what follow is useless, Javac will drop it
			end
		end
	end